Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: Engine RPMs drop while underway

Posted by modenacart on 05/24/09 - 6:30 AM
#1

I have a 1995 Evinrude 88 spl and sometimes while I am underway the power will suddenly drop then return. It doesn't see to do it often but when it does, it tends to do it several times. I advance the throttle and it seems to clear the low power. I think maybe the carboraters need to be rebuilt but I don't want to do that without a second opinion since I am new to outboards. I bought the boat in February and I believe it seat all winter. I have no idea if the person before me winterized it.

Posted by HarleyFXDL on 05/24/09 - 7:02 AM
#2

Sounds like the carbs to me. As dirt gets into the carb, it restricts the constant flow of fuel. This in turn will alter the RPM's. I have had the same problem many times, each time the carb(s) needed rebuild/cleaning. Check the plugs first though, make sure there is no arcing from the boot and the plug has a nice hot spark.

Posted by modenacart on 05/24/09 - 10:03 AM
#3

I didn't notice any arching. I did change the plugs about three months ago.

Posted by HarleyFXDL on 05/24/09 - 6:57 PM
#4

I would say, without looking at the motor, you have a carb issue.

Posted by modenacart on 05/25/09 - 6:22 AM
#5

I was afraid of that. Thanks for the response. I suppose I will be rebuilding the carbs this winter.

Posted by HarleyFXDL on 05/25/09 - 11:15 AM
#6

Check to make sure you are getting adequate fuel to the motor as well. If there is any obstruction in your fuel line, it will not allow the engine to reach proper RPM. I had a problem with a primer bulb once.

Posted by Phil T on 05/25/09 - 2:43 PM
#7

Check the fuel tank vent on your remote tank, then the carbs.

Been there, done that.

Posted by captaincurt on 05/25/09 - 4:35 PM
#8

Good reminder to check fuel tank vent. Last year I went out Didnt get far from ramp ,lost power, I slowed down it was ok .Repeted several times. checked basics 15 mins later cheked vent.Week before had a buddy on the boat,he turned adjusted moved everything that would. Sure enough he turned that also.We had a good laugh and off we went . I told him to sit on his handsLOL

Posted by modenacart on 05/25/09 - 5:36 PM
#9

I have done that too, but stalled. The vents are open on both tanks and both tanks will have the problem. I wish it was the vents. It seems like something will clog then clear.

Posted by Turpin on 05/25/09 - 7:29 PM
#10

One other thing you might want to do, the the fuel line is old or weathered looking replace it, if it doesn't have a fuel filter, install one. Last year when I broke my motor from long term storage the line looked okay but replaced due to a similar issue. If you have my luck it be for naught and you'll have to get your carb(s) tweaked. I usually start at the cheapest options until I spend enough money that would have almost paid the labor of the obivious problem then get irritated with myself. Sorry for the less than clear answer.

Posted by modenacart on 05/26/09 - 7:06 PM
#11

I think its a good suggestions. I will pick up some fuel hose. I assumed the engine had a fuel filter, but I guess it does. I will add one also.

Posted by HarleyFXDL on 05/26/09 - 8:21 PM
#12

To eliminate everything from a motor problem, try using a seperate fuel tank with fresh fuel. If the problem still exists, it is with the engine.

Posted by Mr T on 05/26/09 - 8:59 PM
#13

I have that same motor in a 1990 version. Try cleaning the jets on the carbs.


Pull the big brass screws out of the floats and run a smalll gauge wire into the jets. I used an e string from my sons guitar, but it could go bigger than that.

The upper screw are not hard to get to, but the bottom ones, (there a re two for each carb, upper and ower) are a PIA.

Posted by MW on 05/27/09 - 2:27 AM
#14

If the above suggestion's don't remedy the problem, I would check for a pin hole in the fuel pump diaphram next.

Posted by modenacart on 05/27/09 - 6:20 AM
#15

HarleyFXDL wrote:
To eliminate everything from a motor problem, try using a seperate fuel tank with fresh fuel. If the problem still exists, it is with the engine.


I have two tanks and it does it with both tanks.

Posted by modenacart on 05/30/09 - 11:31 AM
#16

The marina I buy parts from said they will rebuild both collaborators for about 100 dollars. I couldn't turn that down so I plan on having that done maybe next week. He claimed it was a classic sign of the high speed jet being clogged.

Posted by Guts on 05/30/09 - 6:45 PM
#17

A easy to sea if you have arching or a spark issue is to run the engine at night or in the dark with the bonnet off , very easy to sea that way.

Posted by modenacart on 05/30/09 - 7:20 PM
#18

Will give that a try. I still think its a good idea to rebuild the carbs.

Posted by modenacart on 06/05/09 - 12:20 PM
#19

Got the carburetors cleaned for 35 dollars. He took them apart and they didn't need new floats or needles. He clean the body, orifices and other parts in a sonic cleaner. I am happy for 35 dollars. I installed the carburetors and was adjusting the rigging when I discovered a slight water leak at the powerhead while running the engine. Needless to say I am not happy. I hope its not hard to get the power head off. It looks like it would not be too bad. Maybe this is contributing to the random drop in RPM.

Posted by CES on 06/05/09 - 12:25 PM
#20

The power head shouldn't be to hard to remove. be careful with the bolts though as they will break if you're not careful. If possible, use lots of heat to get them out.

Posted by HarleyFXDL on 06/06/09 - 6:09 AM
#21

where is the water leaking from? Some engines used a gasket to seal the powerhead to the midsection. You might want to order it so it will be on hand.

Posted by modenacart on 06/06/09 - 4:27 PM
#22

Its hard to see, but it looks like its dripping from between the head and the block.

Posted by modenacart on 06/07/09 - 12:06 PM
#23

Cracked block. Power head has to come off. Time to decide if to put a rebuilt head on to fix the crack.

Posted by modenacart on 06/08/09 - 2:52 PM
#24

I am going with a rebuilt powerhead. I don't want to put anymore money into a powerhead that is 13 years old and has never been rebuilt and needs the block welded. I will cut back on some of the labor cost with trouble shooting. Right now my estimate to paint the engine and replace the powerhead with a rebuilt one is about 2k. I guess I have to spend my money on something.