1978 Johnson 140 Fuel problem???

[Fishin Dan]

I posted about a week ago about my 140 losing power.
I thought it was a 73 model but turns out it's 78. I went out the other night armed with my timing light, (as per the suggestion) when the motor started bogging down, I checked the spark on all 4 cylinders--all was good. I noticed that the motor seems to use alot of fuel for the short trip. I did take the carbs off and apart and cleaned them a couple months back when this problem 1st started. (which was the 2nd time out with this motor)
It seems the starboard side plugs are always much cleaner than the port side. I'm kinda thinking this could be some kind of fuel issue. It does go WOT 5700rpm at 1st but only for about 30 seconds then slows down, when I let off the throttle and push it all the down again it will go wide open (in gear) and then the same thing over and over. I don't see any signs of water on the plugs, which makes me wonder if there is a fuel blockage. But why would it be the 2 starboard side cylinders? I sure appreciate everyone experience and knowledge.
Thanks again Dan

 

[rickdb1boat]

Re: 1978 Johnson 140 Fuel problem???

Might be a fuel pump problem. Try pumping the primer bulb when this happens and see if she picks up..Also, make sure all your fuel line fittings are tight and leak free from the tank right up to the carbs....

 

[OBJ]

Re: 1978 Johnson 140 Fuel problem???

I remember the thread Dan.

When you checked the spark while the engine was bogging, did you take the engine out of gear and check or while the engine was in the bogging condition?

Being the starboard plugs are a lot cleaner than the port plugs, I would swap power packs and see if the plug condition changes.

Sorry if I seem to have "tunnel vision" on your problem. But two carbs having restricted flow on the same side is not out of the question, but not a real common thing to see.

 

[Fishin Dan]

Re: 1978 Johnson 140 Fuel problem???

It was in gear and bogging when I checked spark. approx. 2500rpm. I did change out power packs on the starboard side with no change.:%

 

[Fishin Dan]

Re: 1978 Johnson 140 Fuel problem???

I also had a buddy pumping the ball but with no change

 

[ezeke]

Re: 1978 Johnson 140 Fuel problem???

You may find that the right bank is running hotter than the left. If you can get a RayteK or other laser meter, it is easy to check.