engine cutting out

[True_Knight]

Hello all,

I have a 1986 johnson outboard that when i first start it and go to full throttel it will run at full song for about 20 sec then in the blink of an eye it seems that 1 or 2 of the three cylinders drops out and i loose rpm's then after about 10 to 15 more mins the engin will again pickup full song and run fine. Any clues what might be happining here.


Brock

 

[rbbrox]

Re: engine cutting out

I had same symtom, it started off working great then bogging down for a bit then wide open up on plane then rpm loss would take me off plane. Ended up having carbs cleaned and sync'd working great other than a surge I'm dealing with now, asking about it on this forum to troubleshoot. Anyway I'm guessing this boat is new to you and you really have no idea how long it has been sitting, other than what seller told you, most likely something like," last time I took it out it ran great" Started right up like a champ on muffs but when on the water under a load, a different story. I had the same senario.
You know what "BOAT" stands for right....
" Break Out Another Thousand"
Good luck..

 

[tashasdaddy]

Re: engine cutting out

Welcome to iboat. lts go back and start over the right way. i have a 1986 ___hp, Model #___. how long have you had it. whats the history of service that you know. Not busting your chops. but if you do this, you will get much better info, as we know what you have. you're our eyes and ears. Again welcome to iboats.

 

[True_Knight]

Re: engine cutting out

Hello again,

Sorry for the lack of details folks, my fault. It's a johnson 70 hp not sure on the model number I've only had it for one year myself previous owner took pretty good care of it. I talked to my repair shop and he seems to think it's the cdi box how does that sound to you all. Great forum keep the answers rolling in.

There's a BASS out there with my name on it.

Brock.

 

[tashasdaddy]

Re: engine cutting out

very possibly a coil going bad. much cheaper than the cdi. that an induction timing light with you , connect to battery as normal, when it starts to cut out. check the spark with the light, on each plug wire. if it's just one, do a complete swap with that coil, with another. if the problem follows the coil you know your problem.

 

[Walker]

Re: engine cutting out

very possibly a coil going bad. much cheaper than the cdi. that an induction timing light with you , connect to battery as normal, when it starts to cut out. check the spark with the light, on each plug wire. if it's just one, do a complete swap with that coil, with another. if the problem follows the coil you know your problem.

Good advice. Also try cleaning the coil grounds.