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Alright so i killed the battery last night bc i forgot to turn off the fishfinder. so when i put her in the water today, she tilted down, and then was dead as a doornob. So a guy nearby gave me a jump. so i went out and started cruising at about 1/2 or 2/3 throttle, and then bumped up to 3/4 or so for like 3 seconds, and all of a sudden it sounded almost like it was pinging. and I lost a significant amount of power. like i could still plain and go prob like 25, but it just didnt sound right. so i figured it was bc of the battery and kept going. got to fishing spot, like a mile or so from when she started pinging, which seemed to go away actually, but still didnt have nearly as much power as usual. almost seemed like i had a much higher pitched prop, till getting on plain of course as the top end was not consistant (as far as the pitch simile is concerned). so then got to the spot, idled for 15 mins bc figd bat wasnt charged yet. (raised rpm idle tho, not idle rpm so to speak, just not ingear) then went to shift into gear, stalled, and thankfully she started right back up, (had plenty of bat power), but she wouldnt idle for long and i had to like rev and shift on the way back down just missing the stall.

then heading back, (after 30 fluke between the 3 of us.... only 1 keeper lol) all of a sudden i noticed the hot light was on. so i stopped. water flowing perfectly well out the back, so not waterpump. fig'd too lean gas? but i mean ive been mixing gas since i was 11, i know i did it right, and i always go a little rich. but whatev, added more oil, lik 5oz, bc couldnt think of anything else it could be. started back up, ran 4 3 mins, hot again. anchored, waited 10 mins, drove another 5 mins, hot again. got kicker running, putted along against the moon outgoing tide up the ct river, barely makin headway 4 20 mins. then started her again and ran 3/4 mile or so back upriver to the launch (15 mins). didnt overheat but still no balls.

What should my 1st course of action be?

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I've got an '83 Evinrude 235 - had the same problem as you up here in Narragansett Bay on Saturday.

First thing is to check the thermostats - one (or both) could be stuck. One of mine was so hot that the internal plastic part had melted. I'm going to replace both thermostats today, and see about changing the head gaskets (may as well do both sides).

Whatever you do now, you'll probably want to replace your head gaskets - you can then see if the overheat caused any permanent damage to any of the cylinders. If not, still go ahead make sure that you tighten the bolts down.

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I have a 1984 Johnson V-4 90 on my 1967 Sakonnet. We have what we call "eel grass" down in southern New Jersey bays. The grass is long and paper thin. It use to get drawn up into the cooling system and get stuck around the thermostats. I know I pulled the thermostats out way back in 1986 to prevent overheats. Has never caused me any grief. Probably have close to 2,000 hrs on that engine.
Wish I could say the same thing about my 1999 225 Merc's...

Just my 2 cents

Norm

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I never thought of that - is it possible to just run the thing without the thermostats in there at all? Crap - I should have pulled the thing out of there as soon as the warning buzzer went off, rather than puttering the whole back to the dock.

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im not sure when the water pump was changed, but it flows out of the motor as strong as ever. And doez anything explain why ive lost so much horsepower?

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I believe that these old Evinrude's have something called S.L.O.W. - don't ask me what it means... but when the engine overheats, it automatically limits the horsepower to 2500rpms.

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Just did a search and found S.L.O.W. = Speed Limiting Overheat Warning.

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First thing I'd suggest is a compression test on each cylinder. Based on the results, I'd pull the heads and do a visual inspection of the cylinder walls and of each spark plug. If there's no visible damage, while the heads are off, you can pull and replace the thermostats as well as clean out the water passages (careful to keep the debris out of the cylinders). When you pick up the new head gasket, ask the parts guy if they recommend the thicker gasket to lower compression a bit (OMC released one for certain models). I'd also pick up a new water pump kit and swap that out, looking for signs of blockage in the screens and housing.

Next take a look at your warning horn to see why it didn't sound on the overheat.

Once it's all back together and running, you still have to be a bit careful as there could be a carb/fuel supply issue that's causing a lean condition.

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Not sure if they had "S.L.O.W" mode in 1979, I thought they were only on the newer engines.

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Yea I was going to say, on my old 95 8hp merc i used to own, there was a rich/lean mixture screw that could be adjusted, and i was wondering if maybe it was too lean. I suppose i should say hoping. But so as far as the compression test is comcerned, are we thinking ive lost compression on one or more cylinders, thus causing the lack of power?

THank you all very much. I'm hoping its simple but dreading the worst.

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Just thinking about your battery. You drained it dead, then jumped it and went fishing. I wonder if the engine wasn't getting enough voltage to run the ignition? Weak spark might help explain loss of power, and poor timing could explain the pinging and the overheating. It pisses like a racehorse so doesn't that mean the thermostat isn't blocked?

Does the battery hold a charge? Can you swap a good battery in and see how it goes?

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I'll charge her when I get home from work. I think the batt is good. but maybe not. I can buy one from walmart if it doesnt hold a charge. GOD that would be sweet if thats the case

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I have an '04 Johnson 50h.p. bought new in '05, last year the thermostat got stuck, the engine ran hot enough to put itself in "SLOW" mode (power loss) but, the water pump was pumping well, and just slightly warm (where it should be) and the "over heat" alarm did NOT trip "ON". A friend put his finger on the cyl. head and went for the "1-2-3" second count (you should be able to count to "1-2-3" second's before you have to remove your finger's from getting burned, this about normal operating temp.) and was pulling his hand off the cyl. head before he got to "2", he said "she's runnin too hot", we replaced the "Thermostat" (took about 20 min's of running to clear the electronic's on the motor afterward's too), and she returned to "FULL POWER". We tested the "over heat" Alarm/horn by grounding it out, and it tripped right "ON" (sys. check chirp's when key is turned on indicating all sys. working too). What I learned was that the engine can get hot enough to throw the motor into "S.L.O.W" mode but, the "Over heat" alarm will not trip "ON". Water pump was doing it's job too, so it was "Confusing".

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I'm pretty sure you're right Matt, I don't remember any SLOW safety on those era engines unfortunately...

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I do not think the motor has gone into slow mode, and don't think it has that feature, but those of you that do have that, all you have to do is run it in reverse for a short period of time after it has cooled down and it will reset to normal.......again, I do not think that is your problem though

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I owned a 1975 115 hp OMC. Your symptoms remind me of a blown power pack, which happened quite a few times during the years I owned that engine. Once I jumped a friends dead battery and I immediately recognized that I blew the power pack. When buying a new pack the mechanic told me that you cannot jump outboards, that it will blown the diodes in these packs. I don't recall any over heating issues, but the loss of power and power surges does sound like you blew out the power pack.

cheers, don

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I don't think that he's in "S.L.O.W" mode either, I DO think that he may be running "Hot" and performance is suffering due to "Thermostat's", "Pump", or blockage of water passages, Gasket, or possibly any combo. of what everyone posted above. I would change out thermostat's 1st (cheapest), then pick up a water pump kit (like Dave said), he's gonna need one anyway, and then move from there to fuel sys. after/if the "Cooling" system check's out o.k.. I'm "GUESSING" Water pump or thermostat's (tough call without engine to inspect).

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My opinion is that the big picture is being missed. Look at the story and not just the end of it, is it possible that damage to electronics could have occurred been or at least upset and just need a fresh charged battery. I know stranger things have happened and all sorts of problems have occurred at the same time but I would look at how all of this started I.E. jump starting the motor. I couldn't imagine that would damage anything but then again look at the issues that have occurred since that incident. Could it have possibly damaged the magneto, stator, coils or power packs which in turn could cause weak spark which would cause a lack of power and possibly other erroneous problems.
It just seems odd that electrical issues would be over looked when all of this happened after jump starting.

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Outboards of this vintage, as long as the ignition system is healthy can run with a stone dead battery. They will generate their own power for the ignition sytem. There have been times where I've had a dead battery, turned the key to the run position, and pull started my 90hp on the second pull. It was a fantastic design.

As far as the cooling system is concerned, you can have plenty of water exiting the water tell tale and have next to no water heading to the power head. Very little water gets to the block if the thermostats are plugged. Once the engine warms, a healthy thermostat opens to allow cool water to flow. If your engine was overheating do to lack of coolant, the cylinders were RED hot. Your pinging (pre ignition) was caused by glowing pieces of carbon on the head that were igniting the fuel air mixture before the spark was firing. Unless your battery will not hold a charge, save your money.

Replace or remove your thermostats before you kill your engine.

Norm

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I have a 1979 johnson 100hp. outboard, & it does have the s-l-o-w mode that it goes into if it is overheating. It wont allow the motor to go over about 2500 rpm until it cools down. If the warning horn is working--you should have heard it go off. hope this helps, Rich

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I was just reading on "The outboard wizard" forum that to "TEST" if you are in "Slow" mode, disconnect the "TAN" wires leading to the "Temp" sensor's, this should allow the engine to go past 2500 rpm (this person had a bad temp. sensor, it was discovered when they moved the wires leading to the temp sensor). The article also states that when in slow mode, the over heat alarm should trip "ON" but, I tested my "Alarm" and it worked with every test, then again, I didn't do a bench test with a known water temp. for the sensor (proper controlled experiment), I by-passed the "Temp sensor" and grounded out the horn to test it. I'm thinking that this would show that the horn work's but, NOT the temp. sensor... Man, we're all over the place with this "one" LOL, but, I think we're gonna "Nail" it !

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Thanks Norm. Makes good sense to me.

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Sounds like cooling to me as well.

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wow guys thankyou so much. So much to do/figure out. I need to first figure out what the thermostats look like. U were saying remove or replace them? So like i could remove them, see if this changes anything, if it does then replace them? and how do I tell if the horn works. or better yet where is it/what does it look like?
The battery is fine, went to charge it, its fully charged.

thanks again guys. Im going to go see if i can find the thermostats, and inspect the plugs now

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Horn...

You can see mine ( horn/over heating single) on the next to last picture and the third to last. It's black round with holes to the right of the aluminum backing plate for the hydraulic helm.

http://whalercentral.com/articles.php...icle_id=89

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The manual I have says that on V4 engines, the thermostat is located between the the two heads and just below the exhaust housing plate in a bakelite housing that contains the thermostat and and a bypass valve. Hope that helps narrow it down some...

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Ok so I just removed the spark plugs. All but one were what I understand to be fouled, which would make sense bc i second guessed myslef, stupidly, about how i mixed the oil as a possible reason for the overheat, and added another 4-5oz to the remaining 5 gallons or so. HOWEVER
When I got to the last plug, i see what understand to be a very bad sign. THe side electrode got mushed down so that its making contact with the center electrode. My manual says that "if the side electrode is bent down onto the center electrode, the piston is traveling too far upward in the cylinder and striking the spark plug. Such damage indicates the wrist pin or the rod bearing is worn excessively. In all cases, an engine overhaul is required to correct the condition. To verify the cause of the problem, turn the motor over by hand. As the piston moves to the full up position, push on the piston crown with a screwdriver inserted through the spark plug hole, and at the same time rock the flywheel back and forth. If any play in the piston is detected, the engine must be rebuilt."
THe italicized part is the part i dont understand. Like as in, what exactly is play? Won't the piston be moving when I rock the flywheel back and forth? If this is true, what its saying is i should be able to rock it and not get an equal response from the piston, like there will be some play in it, like a steering wheel so to speak? Please excuse my ignorance.
Also, how do I know when the piston is all the way in the "full up position"?

And finally, would this explain all of my problems?
-no balls
-what i thought was "pinging" (but remember it didn't
always "ping".
-overheating

And could I have done this when I jump-started it? Or could it be related to the fact that the battery was pulling a hell of a charge off the charge coil? Doesn't seem related to me, but i'm really just trying to look on the bright side, as "engine rebuild" is a scary concept for me.

Again thank you all so much for your help.

-Sean

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I believe I know the plate you are refering to. Not sure if I'm mistaking the exhaust housing plate with the "backelite housing". For now bc its starting to rain and I found this damaged spark plug, i'm going to cover her back up.

On another note, in order to guarantee this is a problem with the wrist pin or rod bearing, after performing the test I spoke of with the screwdriver, if there's no "play". SHould I replace the plug and try again with a full charged battery? Or is it too risky, and I could possibly do more damage than I have already done.

-Sean

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You could put a different plug in that suspect cylinder and just turn the flywheel manually with a socket and 1/2" drive. If the piston hits that plug electrode, you know there's an issue for sure.

I'd recommend pulling the heads, or at least that one. You can get clearer visual confirmation of what's going on and you'll have the piston above (or below depending) to compare it to.

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If you want to find TDC (top dead center) for an individual cylinder use a pencil inserted through the spark plug hole. When the pencil stops moving out of the spark plug hole you have TDC.
I have jump started many outboards throughout the years. I have never had a poor outcome.
You need to address your problems with a clear head, When were your plugs last changed? The fouling could be a result of many hours of service, or caused by the fact that you think you over oiled your fuel. Clean them and try them again or just buy 4 new ones.
Replace or repair your thermastats, Clean the bypass, re-assemble and give her a try. I think you'll be happily surprised.

Norm

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I am going to pull the heads. I just put another plug in that cyl. doesnt seem to be hitting it. but how can i tell? Either way, if it doesnt hit it, theres got to be a reason it hit it in the first place. And I definetly didn't enjoy playing the game of trying to come back up the connecticut river on a moon outgoing tide on the kicker. lol nothing about that was fun. :)

The mushed plug is clean. the other plugs, which were firing after i overmixed the gas, are all fouled. makes sense. and the plugs are under 20hrs old. Put them in under a month ago. battery holds a charge.

hope i answered any unanswered questions.

-Sean

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What is the compression in the cylinders? I'm questioning the possibility of a minor seizure. If you do put this down this might be interesting.

http://www.smellofdeath.com/lloydy/pi..._guide.htm

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Great article on reading the pistons Guts. I especially found the last 2 sentences enlightening, never thought of it that way before:

"When you add extra oil to the fuel you are effectively leaning the carb jetting. This can make the engine run hotter and seize."

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Just the opposite.. lean oil mixture can cause this to happen.

Added
I have never seen a engine size from to much oil. it will smoke and foul the plugs before it seizes. The oil in two strokes lubricate and cool the engine, that's why they use so much fuel.

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over-oiling the fuel will usually make starting difficult. From past mistakes, I have learned to mix my fuel like a "Chemist", I add "Carbon Guard", and a very "Little" bit of "Sea Foam" as a fuel preserver. I ate a ring once on my old 48spl and re-built it, a marine mechanic saw the chewed piston on my desk years later, I said "I guess I forgot to oil the fuel but, I coulda sworn I did it", he stated that the piston was NOT blued, so oil was added, he said that on "Evinrudes" (he knew it was an Evinrude, I never told him) carbon build's up on the ring until it grab's a clip near the cylinder wall and "Crunch", common problem on Evinrudes, and that "Carbon Guard" should ALWAYS be used. He said that "Carbon" was the #1 enemy of outboard's.

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Sean, you're right about the rocking motion test. If the wrist pin or rod bearing (or both) are gone you will be able to move the crank back and forth without moving the piston. If the bearings are still intact the piston will move at the same time as the crank - no play at all.

It will be easier to tell with the heads off. Let us know what you find. Something smashed that plug. It's possible some carbon buildup broke loose and did it. That's the happy ending I'm hoping for. Scrape it clean and put it back together. :)

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Cool that sounds like a good plan to me. I should have a chance to do it tomorrow I hope. Any precautions as far as, I rem someone saying they powerwashed their motor b4 taking the heads off to prevent any foreign materials from entering the cylinders when you take it appart. THink he was talking about car motors though. I was figuring that would be too much pressure on the wires, however maybe some of that engine gunk remover/foaming spray or whatever it is then rinse with the hose...?

And just anything I need to be aware of? (Never done this before so just want to prevent any avoidable mistakes)

-Sean

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What is the compression in the cylinders? post # 32

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not sure. just had it worked on a month ago bc of a no spark mystery, and had him check the compression first. he said "it passed with flying colors". im planning on getting a tester of my own once i have some more money.

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Get one before you take it down, If I'm right ? this might tell you where to look. Just a guess as of what I have been reading here. But I would check the compression before I went further.
Just because he said [the compression first. he said "it passed with flying colors"] dose not mean that something didn't happen.

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by "going any further" do you mean taking the heads off?

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yes!!! It is a little hard to do with the heads off...

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haha, yes indeed that makes sense :)

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Alright so the compression on the 3 other cylinders was 130-135, on the cylinder w/ the mushed plug, it was 113 or so. first time i did it it was about 110, then 2nd and third time was 113. I'm at work right now, but I have to check the manual when i get home. I THOUGHT it said it needs to be greater then 90 or 100, cant rem. COuld be wrong. Oh and as you may have figured, I bought a tester :)

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The absolute values are less important than how even they are. Rule of thumb is within about 10% of each other, so that last cylinder might be OK if they were all that low, but not so good since the other 3 are quite a bit higher.

The next step is to squirt a little oil into that low cylinder and test it again. (WD40 or 2 stroke oil are fine. Couple of squirts from an oil can.) The idea is that if the rings are bad the oil will help them seal and the compression will come up.

Try that next, but like I said before, something smashed that spark plug. I wouldn't fire it up until I was sure I solved that mystery.

I don't suppose you heard a piece of something rattling around in there when you were doing the compression test? . . . . . Nah, I didn't think so.

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dito what theo said

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no i didnt hear anythin rattling. only when it was running. it sounded like it was pinging badly, (probably the plug getting hammered) lol. i will squirt some oil in her tomorrow around 2:00pm. thanks guys

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so was just reading my manual. i had those greater than values in my head from when i was attempting to measure powerpack outputs. lol. but anyway, the manual plainly stated the same as far as the importance of consistency in the levels across all cylinders. one thing, probably a stupid question, but the "cylinder ports" are the ports where the plugs screw into correct?

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I'm waiting to see what happens with the compression with a little two stroke oil... Are you sure you have the correct spark plugs for your model engine. Plugs have different heat ranges, and this makes then different shapes. The ones I ran in my mercury 1000/100hp had no "J" on them they looked like a bull's-eye. When a minor seize happens it could be that one ring is stuck to the piston in only one place, you never know. Lets see if the compression comes up with a little oil. The way I have done it, put the oil in the cylinder then have some one turn the engine over while you put your thumb over the spark plug hole this will allow the oil to seat in the rings and [this will alow the excess oil to blow out past your thumb] then do the test, I have found the hard way that if the oil sits in the cylinder with out doing this it just wants to fill the compression gage with the oil.
....................................................................

A Running Two Stroke Engine...

This will help you under stand what ports are.

http://www.southernskies.net/page_inf...ngine.html
...................................................................

Porting Terminology...

http://2-stroke-porting.com/terminolo...nology.htm
..................................................................

This is a video on porting. I have done this on my jet ski race engines, this guy is a little flakey on this but may help you under stand two cycle port. To port a two stroke, raise the exhaust lower the intake. That's about it. HOW much is where it gets tricky

http://www.youtube.com/watch?v=9-kw9Y...-kw9YOYkg4

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the compression shot up to 120, added a little more oil, blew it out on my thumb again, tested again, went to 140. ANd thankyou those links are quite helpful :).

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OK I say no seizure good news. now what about those plugs?

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i just put a new plug in it, put the muffs on and ran for5 minutes. no overheating no mushed plug... I'm contemplating taking it for a spin (upcurrent of course). and see how she does under a load.. i have a kicker if she overheats again.
-Sean

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What plugs are you using?

Champion ?
QL77JC4 ?
gapped to .030 ?

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yes exactly. sorry bout the delay. i had been using ngk b7hs plugs b4 tho, when the prob occurred. those are gapped to .030 also

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just removed the head. Looks like there was some kind of foreign material inside the cylinder that slammed inbetween the piston and the head a number of times as the top of the piston on the outside and the inside of the head where they meet is all chewed up. cyl walls look ok, im no mechanic, but there is some scoring near where the piston is chewed up. Barely visible but you can diefinitely feel it with your finger

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There isnt anywhere I can post a good sized picture to show this damage is there Joe? besides my personal page, but those pics have to be so small i wonder if you could really see the damage in detail...?

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This could be part of a reed..go back here dose it look like any of these?

http://www.smellofdeath.com/lloydy/pi..._guide.htm

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Ate a ring ? can you see any small black chunk's of metal in the head or piston top ?

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no, no small black chunks. and theres some side to side play in the piston but not up and down, like between the piston and cylinder is tiny movement, but theres actually more movement of that nature in the other good cylinder. lol. So im not too worried about that. And I think I have it pinned down now. It appears what happened is the porcelain around the electrode broke off, then thats what started banging around in there, chewing everything up, mushing the spark plug, (know this bc theres only one mark where the plug would have hit, and if it kept going im certain, judging by the damge it did to the top of the piston and the head, that there would be much more damage to the piston in the middle, had it actually been hitting the plug w/out anything between it. Friend of mine said he could grind it down to make it smooth again, both top of the piston and the head. I'll next replace the thermostat(s), head gasket and the water jacket gasket? Not sure bout my terminology but i pulled both plates off. The plate itself behind the gasket was clogged, with salt, however im almost certain its not waterflow that was the issue as everything else was clear. But so yea replace the head gasket on wither side, as well as that water jacket gasket?. put together and see what happens?

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Side to side is normal, but if you can make the piston skirt hit the cyl wall, it means the rings aren't suspending the piston properly. No up and down means the wrist pin bearings are in good shape. How is your friend going to resurface the piston in the cylinder (or is he going to take it out)?

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Its only side to side, and I'm not sure what the piston skirt is :-/, but i'll do some homework. My friend has some sort of a grinder he briefly spoke of, that hooks up to his compressor I believe. I dont know the specifics of it but im pretty sure hes planning on doing it with the piston in, and the head is already off of course. I think i'll just replace the head though, depending on how it goes with said grinder. does this sound like a bad idea? my main objective is to get whatever life this motor has left in it without rebuilding bc i dont think its worth it..

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When I rebuilt my previous engine (ate a Ring) everything was replaced except the head, it was pretty mangled, and I was reading where there could be "Hot spot's" from it causing trouble, I went down to the shop that walked me through the re-build, I had bought 1 new reed block, and was going back to buy another bank cause, there was also a space in one reed (slightly open). One of the mechanic's came out and said " Kid, Just put it together, the compression will close that loose reed, don't worry about the head either", he was right, IT RAN Great.

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Hard to say without seeing it, but I'm inclined to agree with Matt. I wouldn't get carried away with grinding; just knock the burrs off and don't try to polish it just to make it pretty. Hard to imagine you need a new head, but again, hard to say without seeing it.

The low compression might be because of damage to the rings from the scoring. It will run good with uneven compression, just might not idle that great, and a little less power. You might think about doing a "hand job" on the scored cylinder wall if it seems bad. You can use a small sharpening stone, or a replacement stone from a cylinder hone and just rub it down slightly. Keep it lubricated and don't let crud get down below the piston.

The piston skirt is the bottom part closest to the crank. Like Dave said, the rings keep the piston running true in the cylinder without rocking enough so the skirt rubs.

Nice job of troubleshooting SToomey!

ps - If you start a Project Page I think you get to post slightly larger pictures. . .

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Yes, and the crossflow engines like this one were prone to carbon buildup on the rings, esp on the thrust side of the piston I've been told, so the Deep Creep decarb could help with that. Also, running a newer 2 stroke oil like the XD-50 from Evinrude (BRP) would really help stop any future carbon issues. The "no-name" aftermarket brands of oil are infamous for producing more carbon in the cyl's than the higher quality OEM brands.

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The "DEEP CREEP" de-carbonizer is the BEST, leave it in overnight if you can.

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ok cool. i'll start a project page soon. i have to ask Joe right?

definitely going to deep creep all 4 cyls (see no reason y i couldnt leave it in overnight),
replace head gaskets,
use the high grade name brand 2cycle oil,
and i'll get pictures of the head and the piston up soon.

thank you guys SO MUCH. i'd be 50k feet, no plane no parachute if it wasnt for all your mentoring and advice. i tend to act impulsively at times, and i have to say, Dave (derwd24), has at least on one occasion kept me from blowing her up lol. my highest thanks to you all, and esp to Joe for making this awesome site possible. talk to u soon with the latest :)

-Sean