Boat Motor Problems....

[GreenF350]

I was wondering if we had anyone on here that knew much about Evinrude boat motors. I have one that is having low RPM/Idle issues and was looking for some help troubleshooting it. Here is the condensed version of the problem.

1991 40hp Evinrude (E40ELEIA) Rebuilt powerhead and carbs. Run great above 3000 rpm's but runs rough under 3000 rpm's and eventually dies at idle. Tach will jump up intermittently below 3000 rpm's to what I judge to be double the actual RPM's. Carbs have been cleaned, coil replaced, linkage and carbs adjusted numerous times. It seems to be ignition related due to the tach issue, but it's possible it is just a coincidence. I can give more info if needed, but thought I would see if anyone thought they could help.
-Aaron

[Diesel Nick]

Rough idle as in misfires? You don't have wires listed I would check your wires get a water bottle and spray water on the wires and see if you see a little light show. If no light show then I would check for any vacuum leaks they can cause rough idles and misfires. If you can't find anything from that I would turn to the timing check your timing make sure your belt isn't missing any teeth if that engine has a timing belt (If it has a chain then just check the timing)? If your timing is good I would pull the head you make have a burnt valve...

[dustindiesel]

kinda sounds like water in the fuel but im sure u checked that already...

[Justinlw]

No burnt valve or timing belt.....it's a 2 stroke. I would check the power pack that controls the coils. There should be an OHM test procedure in your service manual. I had to replace that on mine not too long ago, same symptoms. Same motor also, pretty much. My Carolina Skiff has a Johnson 40, '90 model I think.

You could also check the magneto under the flywheel, sometimes the vibration knocks the pick-up loose and causes a bad reading.

[GreenF350]

Originally Posted by Diesel Nick

Rough idle as in misfires? You don't have wires listed I would check your wires get a water bottle and spray water on the wires and see if you see a little light show.

Sorry, I did check spark plug wires too. They are ok. The motor is a two stroke so no valves or timing in that respect.

Originally Posted by dustindiesel

kinda sounds like water in the fuel but im sure u checked that already...

Shouldn't be. I just siphoned out all the old stuff and put new fuel in. I just got the boat and wanted to make sure.

Originally Posted by Justinlw

I would check the power pack that controls the coils. There should be an OHM test procedure in your service manual. I had to replace that on mine not too long ago, same symptoms. Same motor also, pretty much. My Carolina Skiff has a Johnson 40, '90 model I think.

You could also check the magneto under the flywheel, sometimes the vibration knocks the pick-up loose and causes a bad reading.

That is kind of where I was leaning. I will work on checking that out. I need to go to the hardware store for a bolt today. Somehow my flywheel got on tighter than usual and I ended up breaking a bolt for my puller...lol. It is still lined up on the keyway and whatnot. I think the nut just got over tightened. Anyway, I'll be back with more questions or to let you all know how it went. I can't wait to get out and start fishing.
-Aaron

[GreenF350]

Well, Justinlw called it. It was the power pack/ignition module (name is different depending on who you talk to I found out). I changed it out this afternoon and it runs WAY better now. I love this site. Go figure, I get the help I needed on the diesel site, not the boat forums, been trying to get help from them for 2 weeks. Gotta love this crowd. Thanks everyone!
-Aaron

[Justinlw]

glad you've got it going. When are we goin' fishin'??