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1979 evinrude 85 hp starts ok will rev up to about 5000rpm's ,but once engaged motor doesn't want to pick-up speed and won't rev up pass about 2500-3000 rpm's.bulb is solid,it will rev a bit higher if i push in key to choke it for only a sec or two.ran great right after i purchased it. drained and put in fresh fuel.still the same results.any suggestions besides taking it to the shop.thanks for any helpful hints or clues on what to do or try.

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These old outboards are easy to maintain. Check the carbs for dirt or old fuel gum in them. You can by a carb rebuild kit at most OMC dealers or even on ebay. Plenty of parts are still available. Also check your ignition system. You could have a weak coil or bad spark plug wire. Also while you are working on the motor go ahead and de-carbon the engine. Use either OMC Tune and Lube or Yamaha Ring free. Follow the directions on the bottles and you'll be amazed how much gunk and carbon will come out of your motor.

Goto the following link and do a search for your problem. Lost of good info and tech info here: http://www.outboardmotor.biz/

Mark

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I agree with Mark, check the carbs.

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Yep, carbs.

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Could be runnning without one of the cylinders/plugs firing. Pull the plugs and give them a look. Or, you can check the cylinder temps at the spark plug while running, with a infrared thermometer. The cool cylinder isnt firing. Also, check the spark plug boots. Many times at high rpm's the spark can jump to the head if the boots are bad or loose.

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Is the engine running rough?

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First thing I thought of was the carbs too.

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I suffered with this twice this season alone . Both times were related to water in the gas. Thanks to ethanol.

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The fact that it picks up when you use the primer is a clear indication that the motor is not getting enough fuel at high speed. It's time to rebuild the carbs. That is not a difficult job, and the rebuild kit is only about $30. Do not continue to run the motor in its current state, as it depends on sufficient fuel for lubrication and cooling.

Also, revving the motor to 5000 without it being in gear is a really, really bad idea - the motor can "run away" making it impossible to shut off.

Tim

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I might suggest if you have some kind of air cleaner, remove it and run the engine. It dose not have running fast around 1000 rpm. Put your hand in front of the carburetor not to block the flow of air but close then remove your hand and inspect it for any Gas being spit back from the carburetor. If so this will indicate a bad or sticky reed. This is my thought on this, as I had this happen before with the same symptoms'. Also ditto on
"DWinter" comments.

It is easy to see a bad spark plug wire / coil wire if run at night or in the dark.

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Another neat way to check for a broken reed, if you're running the engine at night to look for spark bleed, is to use a timing light. Aim it at the carb and look from the side (not down the throat) to check for spit back coming out of the carb openings. Shine the light on all carbs, one at a time, then move the pick up lead to the next cyl and check again.

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Not sure if you guys noticed the reported symptom of an increase in maximum RPM when the primer circuit was used. I don't see how that would occur if the underlying issue is an ignition problem or a broken reed, but maybe I am missing something.

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well thanks for the help.bought some sea foam ran it thru about 1-2 gals out of tha tank and wow motor ran like it use to.still going to rebuild carbs(not very mechanical inclined )so i'll problably back asking more questions.agin thanks for all your fast responses. BUD

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Good to here that you are up and running again. sounds like you had some gumming in the fuel supply or sticky reed . keep us posted OK

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Bud, if it's running well, leave the carbs alone! It's not hard to rebuild, but if the motor is running right, rebuilding them is not going to make it run any better. Running Seafoam through it occasionally will keep things nice and clean.

Tim

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Now that it is "running ok", keep an eye on the plugs. Pull them every few hours to check the color. If one or more is running too lean it will show up on the plug with a very lignt color. If you get this, rebuild the carbs before you use it too much. Running lean will burn something.
Mike

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ok Moose,running lean is what exactly as i stated not very mechanically inclined?willing to learn and try.what should i be looking for ?i think i know when they are fouled (plugs)covered with black or smutty residue,right.

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Running lean is when the cylinder doesn't get enough fuel. This is worse than running rich (and fowling the plugs) because the fuel entering the cylinder both cools it and contains the lubricating oil, and when there's not enough, the cylinder will fail from overheating and excessive friction, usually resulting in extensive damage.

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Thanks Dave.
budana, google "spark plug color chart" and you will get all the info you ever wanted. Many of the sites describe what causes different colors and the result to the engine. All good info.
Mike

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well took boat today problem started again,uhhh,took along spare tank to check how it ran with different fuel source.no change after couple hrs motor warmed up well,motor ran fine friend said at first it was carbs later said he didn't know what could be problem.thinks it could be trash some where in between tank and carbs. thanks for the plug site.

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Rebuilding the carbs can do no damage to your motor, but, a lean condition can. There have been instances when a motor was perceived to be running fine, just to have a rod bearing go. I have such a motor in my garage right now. If you don't know when the carbs were last rebuilt, it can't hurt to have them done, it might save you from a possible problem next trip out. Just my .02, no change required.

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i know i'm going to do a carb rebuild just because,ran motor today in driveway started fine .one thing i forgot to mention was that at low idle motor would sputter and stop .today not aproblem at low idle. can't wait till i can get money saved to buy new 4stroke or e-tec.lol.

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How old is the primer bulb and fuel hose and fittings?

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Forgot to add, if you do not have a fuel/water separator, make sure you install one PRIOR to running engine with fresh carb rebuild.

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I would take the engine in for service. I don't know anything about OMC's, but on a Mercury when the engine won't go over 3000 RPM, it's a high speed stator failure. Your problem may not be in the carbs.

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thanks harley,i purchased one last year,before i got the bw for another boat.i look up a carb rebuild i think i can do it.if i get in a bind expect a pm,lol.thanks BUD.

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I don't know if you found your answer.. I didn't take the time to read all the reply's, but I have ran in to this problem before.. with a Brand New Engine... my problem was a mismatched PROP. And I suspect that is your issue also.

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besides the carb rebuild i think after reading about ethonal blended fuels and fiberglass tanks i think it might be adding to my problems.have a Pate tank and all the stations now are selling blended fuels.been looking into getting a different prop too.