81 35hp cutting out?

[redfordjeff]

my motor will run great for about 15-30 min then starts cutting out and will only run about quater throttle if i shut it off for about 20 min its good to go again. but it will sit there and run at idle or quater throttle all day and not miss a beat. I cant figure it out?

 

[dsinger]

Re: 81 35hp cutting out?

what does the primer bulb feel like when that happens. Sounds like you are sucking air but need to know what you have done thus far. What do the plugs look like could be a hot pack and you are missing a cylinder when the pack gets hot.

 

[redfordjeff]

Re: 81 35hp cutting out?

the primer bulb isnt hard but seems to have fuel in it I have changed fuel tanks and pulled and cleaned the plugs and cleaned the fuel filter do you know exactly what spark plugs should be in this motor?

 

[dsinger]

Re: 81 35hp cutting out?

Champion l77j4

 

[tashasdaddy]

Re: 81 35hp cutting out?

check spark when this happens, could be coil getting hot and failing. classic symtoms. they will run on one cylinder, but have no power when throttled up.

 

[redfordjeff]

Re: 81 35hp cutting out?

thanks i will check that i noticed that some of the gel in the coil pak looked like it got hot and leaked out but not much the champion l77j4 is that the one that is flat on the end?

 

[tashasdaddy]

Re: 81 35hp cutting out?

if it's leaking replace it. i think so.

 

[ezeke]

Re: 81 35hp cutting out?

Use the QL77JC4 set at .030: http://www.boatsetup.com/SparkPlugChart.pdf

It sounds as though you may not be getting air to your fuel tank. Make sure that you have a good vent. You may also have an obstruction somewhere in the fuel line.

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[redfordjeff]

Re: 81 35hp cutting out?

thanks im going to get some new plugs tommorow i thought the ones in there were the wrong ones that could be alot of my problem

 

[fireman57]

Re: 81 35hp cutting out?

Save some time. tdaddy's right. Your coil is overheating and cutting out. Replace it. Takes about 5 minutes and your problem should be solved. Correct champions are a must.

 

[Captain Caveman]

Re: 81 35hp cutting out?

Keep me informed. My '79 35hp Evinrude started doing the same thing last year. For me it's not a fuel problem but some kind of electrical short that reduces me to one cylinder. Replacing the ignition coil did nothing and replacing the power pack helped short term but never solved the problem.

 

[tashasdaddy]

Re: 81 35hp cutting out?

caveman, have you tried swapping the postions of the coils, if the problem follows the coil it's bad. the other coil could have gone. even the new one.

 

[Captain Caveman]

Re: 81 35hp cutting out?

Yeah, I swapped coils.

I don't want to steal the thread from "redfordjeff" though, so I'll just watch the posts.

 

[ezeke]

Re: 81 35hp cutting out?

Edit
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[redfordjeff]

Re: 81 35hp cutting out?

not bothering me any maybe we can figure out both of them!

 

[Captain Caveman]

Re: 81 35hp cutting out?

I need to get out and test the wire connections on everything inside the motor. Unfortunately, it hasn't been warm enough in MN to run the outside hose so that I can put the water muffs on my motor.

I know that one of the threads for an ignition coil is stripped, but it's not the one with the ground wire attached. I doubt that has anything to do with it but I'm going to try rethreading it with my tap and dye set.

Otherwise, I've heard that the cut-off buttons on old OMC motors can be problematic. I want to trace that but have heard from folks in this forum that a bad cut-off button wouldn't reduce me down to just one cylinder.

 

[fireman57]

Re: 81 35hp cutting out?

Captain C what year is your 35? If you replaced the coil yourself you probably had to put the coil wire in yourself. Sometimes these can be a bugger to seat correctly. Use a timing light and see which one of your cylinders is dropping and we'll go from there.

 

[Captain Caveman]

Re: 81 35hp cutting out?

Mine is a 1979 Evinrude 35hp.

I didn't do any tinkering with the motor all summer. One time out on the lake, it just cut down to one cylinder (the top) for the rest of the trip. I installed new spark plugs with no result. I got home and switched the coils around. The same cylinder still would not fire. I bought a new power pack and it fixed the problem. One month later out on the lake, the same thing happened. I was puttering along at slow speed and all of a sudden it dropped a cylinder. It was the same all day. That night, it all of a sudden was running on both cylinders again.

The coil was a pain the butt to seat but it works when running on the top cylinder. The bottom cylinder is the one that cuts out.

 

[fireman57]

Re: 81 35hp cutting out?

'Bout all you can do for now is remove and clean all your connections well. Don't just look at them but physically remove and clean them. I hate intermittent problems.

 

[Captain Caveman]

Re: 81 35hp cutting out?

Great point. We've finally got a weekend in the 50s so I'll be able to get to it. Thanks.