1985 Johnson 8hp running rough

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Fisherman6
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Re: 1985 Johnson 8hp running rough

Postby Fisherman6 » Mon Apr 16, 2018 3:34 pm

Unless you have a large fan blowing the exhaust away from the intake, the exhaust in the barrel can cause plenty of idling problems. Try the boat test and let us know how it goes.
-Ben
Ben Breitner
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davesko
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Location: Hershey Pa

Re: 1985 Johnson 8hp running rough

Postby davesko » Mon Apr 16, 2018 3:52 pm

Thanks Ben, Got my big run fan out and she runs well. Going to boat test soon.

crosbyman
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Location: Montreal Canada

Re: 1985 Johnson 8hp running rough

Postby crosbyman » Mon Apr 16, 2018 4:39 pm

yep.... getting sick and sputtering sucking up exhaust.... or lack of oxygen ..

I have a 9.5 turtle in the basement that I purchased ..... came with a 2 inch lobotomy close to the carb to let the air in :shock:

James Davis
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Re: 1985 Johnson 8hp running rough

Postby James Davis » Mon Apr 16, 2018 9:48 pm

sounds like the hood is blocking something, air, or pinching line. has to be restricting something if it runs fine without it.

PugetSoundBoater
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Re: 1985 Johnson 8hp running rough

Postby PugetSoundBoater » Tue Apr 17, 2018 12:32 am

There is a open vent baffle hole in the back of the hood handle or down in the lower cowl below the carb that is open to the outside that lets air in. Could that have become restricted? I know it sounds like a long shot, but as Don says "never say never". You never know what a previous owner has done. Many of us have seen some pretty odd "repairs" done for unknown reasons.
"We only learn in two ways,one from reading,the other by association with smarter people" Will Rogers

fleetwin
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Re: 1985 Johnson 8hp running rough

Postby fleetwin » Tue Apr 17, 2018 10:01 am

OK, are you saying the engine runs OK with the hood off, but messes up with the hood on? You have replaced the fuel pump and it acts the same way, correct?
If indeed the engine runs poor with the hood on, it probably means one of two things...
And exhaust leak under the hood...This should be fairly obvious, black soot/oily residue, noisier due to exhaust leak...
Plugged up air inlets....I think the air inlets are under the hoods lift handle, thin little slots back under there. Perhaps there is some paper or tape plugging them up....
And yes, you can not judge much running in the tank. Crazy water flow, and the tendency to breath its own exhaust just adds confusion to the issue...Try it out on the boat, try to make a video if the engine is still misbehaving...

davesko
Posts: 141
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Location: Hershey Pa

Re: 1985 Johnson 8hp running rough

Postby davesko » Tue Apr 17, 2018 10:50 am

Hi Don, I changed the fuel pump and it seems fine even with the hood on. It was idling rough until I put my big fan on it. I’m going to boat test this weekend and know for sure. It’s always been a good runner till I loaned it out. Lol. I see no signs of exhaust leakage underhood so I think it should be good. Thank you


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