1978 Evinrude 35HP acting up

[johnny whaler]

I have this 1978 Evinrude 35 HP long shaft on my 1963 13' whaler. It ran great but was not pumping well, I changed the thermostat. Then it ran good but seemed to suck somethign up in the carb. I had the carb off and had it cleaned. The shop said there was a chunk in the jet area and I put it back together and it ran great today for a solid 90 minutesof high speed, low speed and on and off abuse. I came WOT into the break walls and then shut it down and it started acting up all over again. Kind of like it was loaded up. It wouldn't rev up high. If I let it idle for a little while it would somewhat clean out and then rev up again but then do it all over. It got to the point that it was even breaking up on the high end.
I put it in the dock and put it in Neutral and it even took a while to "blow it out" and get the engine to rev up.

The carb was cleaned, the gas tank is brand new, the ful line is brand new BUT I did notice that the entire inside of the engine housing had all the paint bubbling up like from paint stripper but it was from the carb cleaner. I also noticed the foam insulation in this 30 year old engine was pretty much shot and easily came off in small chunks. Call me crazy but if it ran great for 90 minutes after a good carb clean and then got bad all over again would anyone suspect the foam or the carb cleaner bubbling up the paint could be the effect all along? I've done more stuff to this thing and I bet it was just a dirty inside of the engine. Has anyone heard of this? Would it really suck enough to pull some of the paint or foam inside the carb? I'm guessing if it did I need to remove the entie carb again and simply unscrewing the float drain wont do it?

Help if you can....thanks...I will take any sugestions!!!

 

[johnny whaler]

Re: 1978 Evinrude 35HP acting up

I'm doing some searches here. Does anyone think this could be a bad coil? Does the trick with the hair dryer heating them up work while it's in the garbage can running?

I'm baffled with this engine and the fact that it ran great for 90 minutes and got bad again.

 

[clint]

1978 Evinrude 35HP acting up

It does sound like it is an electrical problem. Coil would be suspect, but do check for spark in each cylinder. Make sure ignition switch is on. Plug could be fouling also.
Clint 8)

 

[tiller7104]

Re: 1978 Evinrude 35HP acting up

I posted in the force forum last year in reference to why my fuel bowl was always full of crap, and why my prescreen for the fuel pump always had crap in it. Well it was the foam starting to crumble and clogging up my carbs !!! So it does happen and I try to cut off any and all foam away from the air inlet.

I do agree with johnny and clint I think it sounds electrical to me as well!

 

[johnny whaler]

Re: 1976 Evinrude 35HP acting up 1976 or 1978??

Re: 1976 Evinrude 35HP acting up 1976 or 1978??

I just called the local marine parts house for a tune up kit and found out my engine is a 1976?

The Numbers are as follows:
35653S
L0001780
I thought the 780 indicated it was a 1978 but the parts woman told me it's a 1976.

Just to update the problem. I got it in the barrel and had it running. I pulled the top plug wire off to find NO CHANGE in the way it was running. I got a good shock too. I put it back on, pulled the lower wire and the engine died.

I changed the plugs, fired it up, seemed to run good for about 30 seconds (maybe my imagination) and it did it all over again. I have FANTASTIC Compression 125 in each jug, FANTASTIC HOT spark from each wire. I could hold the plug 1/2" awar from a cyl head bolt and the spark jumps.

I did notice the top coil is green and the bottom is black so one was replaced, my guess is the green is original but the spark is excellent. What else could it be? Bad set of points? Bad coil? timing?

The carb was definitly bad because it ran great for 90 minutes. I am starting to think the long hard 90 minute ridemay have taken it's toll on the points on one side ( I asume there are 2 sets of points)???? Maybe they are burnt? The amazing thing is this thing got me back in. The other questions is that it did come back to life a little here and there. I thought coils and points were either good or bad with no in between???

I'm getting somewhere. This engine is too good to bring to the scrap yard.

 

[johnny whaler]

Re: 1978 Evinrude 35HP acting up

One other thing, if htis thing is actually a 1976 i've ben running l77jc4 plugs but it is suppoed to have ul81C plugs. How different are these plugs and why id it run well for 90 minutes on them? and why would only one be fouling? maybe a slighter weaker spark?

I'm going to buy the ul81c plugs now. Any guidance is appreciated.

 

[jfm1]

Re: 1978 Evinrude 35HP acting up

I would try to clean the carb again, it has good spark and compression

 

[F_R]

Re: 1978 Evinrude 35HP acting up

Loose foam could get sucked in thru the carb throat and lodge in the reeds, holding them open, causing it to not run on that particular cylinder. I fail to see the logic suggesting it could get into the fuel lines and filter and stuff, or inside the fuel chamber of the carb. But it could lodge ahead of the butterfly plate. Save your money on the UL81 plugs. Use L77JC4 or QL77JC4

 

[clint]

Re: 1978 Evinrude 35HP acting up

I would use L77JC4. Much better for your engine.
Clint 8)

 

[johnny whaler]

Re: 1978 Evinrude 35HP acting up

I would use L77JC4. Much better for your engine.
Clint 8)

whay are they better? Just curious?

 

[tdcoats]

Re: 1978 Evinrude 35HP acting up

i have a 78 evinrude but its a 25 horse. i got it and the boat and motor from my uncle. the internal part of the wiring harness was burnt. does any one have a diagram? id really appriciate it. thanks, trevor

 

[Rosco 11]

Re: 1978 Evinrude 35HP acting up

Hey there Johnny,
I have a 1976 35 hp Johnson, and while there might be a small number of differences, they very similar.
Mine went thru it's share of problems, too . . .but now that I have done same basic maintenance, the old girl has been running pretty sweetly for about 2 years now.
I also had an issue similar to your post. Mine would start out fine, then after about 45 minutes total of running around , moving from spot to spot etc, it would not rev high. It would start off running fine, then muck up later.
It turned out to be a faulty condenser . It lives under the flywheel. You might want to change your points while your there.
Be careful when changing these electric gizmo's under the flywheel . . . make sure that the connecting wire is totally and safely below the spinning flywheel.
Otherwise you will find it goes brilliantly for about 45 seconds, then stops.

Yours might be a totally different problem, . . . you never know.

Funnily enough, I also had some drama's with plugs .
I live in sunny Australia, and the OMC recommended " Champion " brand plug is discontinued over here. So I ran with an NGK eqivalent ( B7HS ). Was in a parts shop one day, and the guy looked through his Champion product book, and showed me the comany's own recommendation for a subsitute.
To cut a long story short . . .it would not even fire with the Champion plugs in it. I would immediately take them out, put the NGK's back in it, and it would start first time. Being both hard-headed and inquisitive, I immediately took out the NGK's and put the Champions back in. Same result. No fire whatsoever.
I suppose they could have been faulty . . .but highly unlikely that Both were duds.
So now I run the NGK's, and they are great.

I got all my knowledge from this forum. I'm no mechanic, but I now do most maintenance like head gaskets, t-stats, cables, shift rod connectors, impellers, etc.
Lots of blokes helped me back then. Fireman, GDANE, OBJ, Dale, Joe and many more.
Listen to the advice you get here, and as long as you can tell the difference between a ring spanner and a socket . . .you are on your way ! .
Good Luck .

 

[Deanrt]

Re: 1978 Evinrude 35HP acting up

I have the same motor and it's been a complete nightmare. It did run good a couple times but there is always something. Pulling the flywheel is a good idea, I had, at different times both condensers actually come unscrewed in there and just wasted em.