Logo

1979 Johnson 6HP will idle wonbt rev

E

empaynejr

Guest
"I have a 1979 Johnson 6HP, mo

"I have a 1979 Johnson 6HP, model# 6RL79E, that I use on a 22' sail boat.

I can get it to run just above idle, but when I open the throtle more it just stalls. Any suggestions? Seams like fuel delivery problem but I am not sure.

Also, what should the gap on the sparkplugs be?"
 
"QL77JC4 gapped at 0.030"

"QL77JC4 gapped at 0.030" is the current plug recommendation. (QL86C can also be used)

If you have a fuel delivery problem you can verify it by pumping the priming bulb. If you can get it going by doing that then be looking at air leaks into the fuel line or at the connection to the engine, or (unlikely) a restriction somewhere, or a defective fuel pump.(you've checked the tank vent I guess)

I think any of the above will have a gradual effect anyway ie initially it would rev but then die as the carb bowl is emptied.

If it is none of these then I reckon you need to do a full carb clean, especially the high speed jet. I think that is what you will end up doing. Probably worth getting a full carb overhaul kit which will contain everything you will possibly need."
 
"VicS, Thanks for the tips. I

"VicS, Thanks for the tips. I am an accountant not a mechanic so I am sorry if these questions seem...stupid.

QL77JC4 is the plug I am using but the old plugs were gapped at 0.045". I will reduce that to 0.030".

The tank vent is open and so gas can flow from there. I can pump the primer bulb until there is resistance but I cannot pump any more and there are no visible fuel leaks under pressure. When the engine is at idle and I try to pump more it stalls.

The engine will run just above idle for quite some time and not falter or vary. Then when I open the throttle or apply pressure to the primer bulb, it stalls.

My impression is that the pump is having difficulty keeping up with the fuel demand above idle. Is there any way to test that? If the pump has a problem, is it something that you rebuild, or replace?

Regarding the carb...someone suggested running some carb cleaner through it. How exactly would you do that since the intake is horizontal? Would that be effective in cleaning some of the carb out?

Thanks again for your help."
 
"The recommendations for plug

"The recommendations for plug gaps have changed. I'm surprised at 0.045 mine was originally 0.040 but like virtually all the omc two strokes .030 is now recommended. I only recently found out about that! Don't ask, I don't know why!

I don't understand why it stalls if you apply pressure to the bulb. Perhaps you are forcing fuel past the needle valve that controls the flow and you are flooding it.

Just gentle pumping of the bulb will keep it going if its the pump as then it's you doing the pumping.

i am afraid the only way to clean carb properly is to dismantle it soak the jets etc in cleaner then blow or even poke them clear with something that won't scratch them. Just spraying cleaner into the intake wont reach the parts that need to be cleaned."
 
"Dear VicS,

Thanks for your


"Dear VicS,

Thanks for your help. I had the carb cleaned and went over everything from top to bottom and it is running fine now. It is a little hard to start when cold but once it warms it runs like a charm. Looking forward to nice sailing for the rest of the summer.

I got some advice to use a fuel stabilizor and it will reduce the build-up in the carb. That is something that I will start to do.

Best of luck to you."
 
Back
Top