Evinrude 1982 70 Horse Good for a hour

[S.S. Corrosion]

I have a Evinrude E70ELCNB and she will run great until being on the water for about an hour or so...then it will only idle and runs really rough...If I put it neutral it will rev right up....But then when I put it in gear it will just idle and not have any power at all...
I don't know if something is getting wet or if something is getting hot....I can put my hand on the motor for a 5 count and it doesn't feel hot....

 

[jbjennings]

Re: Evinrude 1982 70 Horse Good for a hour

It definitely sounds like an electronic component is heating up and failing. You should take a spark tester with you and check for spark when it starts fouling up. Almost surely you won't, and you'll have to go step by step doing tests to see what the offending componet is. You might have to heat some of the parts up at home with a blow dryer to the operating temp. of the motor and see which is failing. Tough to identify a part failing due to heat.
Good luck,
JBJ

 

[S.S. Corrosion]

Re: Evinrude 1982 70 Horse Good for a hour

Thanks JB, I will definitely try warming the components up and checking the spark....Why do you think it will rev up in neutral though?

 

[jbjennings]

Re: Evinrude 1982 70 Horse Good for a hour

Motors running on only 1 cylinder will actually idle fairly well and seem to rev up in neutral, but don't have enough power to do squat under a load. I'd bet a bunch that you're losing spark on at least one cylinder.
Welcome to the forum, BTW.
JBJ

 

[Mark42]

Re: Evinrude 1982 70 Horse Good for a hour

I'm going through this right now with a 2003 90 hp. After about 1 hour, it starts misfiring, then will only idle, and very rough. Motor is not overheating. Sounds like your situation. I checked the stator for continuity, and resistance, and it checks out OK. Also checked the SLOW feature by grounding out one of the temp sensors when it was running well, and the motor went into SLOW mode, but did not shake and misfire like it does when hot. Not sure if your year has SLOW but you should check a manual to see.

Is the tach working correctly when its running bad? My tach is OK when the motor is running bad, and that indicates that at least part of the stator is working OK. So I don't think its the stator.

At this point, i think its the powerpack, and have a new one on order. Coils are cheap, so a pair were ordered too.

 

[S.S. Corrosion]

Re: Evinrude 1982 70 Horse Good for a hour

Makes alot of sense....My brother ordered new plug wires and I think I will try to troubleshoot when I get the chance....thanks again

 

[S.S. Corrosion]

Re: Evinrude 1982 70 Horse Good for a hour

Mark42 I would check the tach but this motor is older than I am and is missing ALOT of components..Me and my brother bought the boat cheap and have fixed alot of things on it, but haven't made it to the tach yet...does have the wires though...I am looking right now on iboats for a powerpack and stator