Evinrude 70 3 cyl two stroke lack of power.

I got suckered by my in-laws whom think that because I am a GM auto tech that I can fix anything with a piston. Anyways I am working on a Evinrude 70 3cyl two stroke outboard, not sure what year. It starts and idles fine after installing plugs and fuel filters, along with all new fuel lines. The engine had a miss and would lose prime. Now it has very little power to the point if you put it in gear and take it off idle it will stall. I tried to spray carb cleaner in the intakes while throttled in neutral, which made it worse. I did see fuel dribbling out of the top cyl carb intake snd have an occasional fuel spray. Instantly I was thinking float, needle, and seat so I removed the the three cabs and left the lake. Later I did some reading on this forum and came across an old post about reed valve symptoms. Could this or something else be my problem or should I concentrate on the carbs.

Engine has 125 PSI compression on all cylinders, old fuel filters were very old, but carb bowls are clean. Has fresh fuel with "heet" in tank for possible water intrusion. The outboard is on an old house boat. Any help would be great o if you have GM car or truck questions feel free to message me.

Re: Evinrude 70 3 cyl two stroke lack of power.

Did you check the spark on all cylinders? A bad reed valve will usually let fuel mixture spit back out of the carb, like a burnt valve on a car engine. It might be time to overhaul the carbs.

Re: Evinrude 70 3 cyl two stroke lack of power.

Daviet said:

Did you check the spark on all cylinders? A bad reed valve will usually let fuel mixture spit back out of the carb, like a burnt valve on a car engine. It might be time to overhaul the carbs.

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Yes I do have spark on all cylinders. I am ordering carb kits on Tuesday, as for reeds maybe put some in for good measure? What the heck just like automotive if you cant diag. yourself out of a wet paper sack throw parts at it lol. Thanks for the help.

Re: Evinrude 70 3 cyl two stroke lack of power.

I wouldn't replace or get reeds just yet, reed valves are pretty tough. After carb/s come off, take a flashlight and look to see if there broke or missing.

Re: Evinrude 70 3 cyl two stroke lack of power.

If the reds were bad it woudl spray out the throat all the time, once and while isn't abig deal, I would just do the carbs and see where you are at of coarse changing the reeds won't hurt anything either but I woud lean towards carbs.

Also if you haven't get an inline filter on it, that will keep you from messing with carbs in the future, the engine mounted one works okay but better to have an inline too.

Re: Evinrude 70 3 cyl two stroke lack of power.

have you checked the fuel pump diaphraghm (spelling?) it may have a small pin hole, or be stiff from old age and starving for fuel, past idle.

Re: Evinrude 70 3 cyl two stroke lack of power.

5150abf said:

If the reds were bad it woudl spray out the throat all the time, once and while isn't abig deal, I would just do the carbs and see where you are at of coarse changing the reeds won't hurt anything either but I woud lean towards carbs.

Also if you haven't get an inline filter on it, that will keep you from messing with carbs in the future, the engine mounted one works okay but better to have an inline too.

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Dually noted... I had problems with my 70hp Evinrude this weekend. It ran fine at first and then stumbled to a sad 4k rpm and limped back to the dock. Went out minutes ago to find all kinds of junk in the inline fuel filter before the pump. I would definitely start there!

Re: Evinrude 70 3 cyl two stroke lack of power.



junked up inline filter... suprised it even ran

Re: Evinrude 70 3 cyl two stroke lack of power.

Thanks for all the info everyone. I was looking for something else because the carb bowls were spotless. But noted I will look at reeds closer just need to drive to the lake.