79 Johnson 55hp, Possible fuel system delivery issue.

[djdarren]

I have a 79 johnson 55hp. It will start and run at dock, will idle sometimes but not always, when I get out on the water just cruising in my bay it will run for about 5-10 mins at max and then quit and will not want to start again. Any suggestions would be greatly appreciated, im not the best mechanic but im learning as I go. Thanks!!

 

[Daviet]

Re: 79 Johnson 55hp, Possible fuel system delivery issue.

Can you get it to restart? What do you have to do to get it started? You might have to check spark when it fails and see if you have spark. Have the carbs been overhauled lately? If you can catch it before it stalls and pump the primer bulb, will it pick up and run?

 

[djdarren]

Re: 79 Johnson 55hp, Possible fuel system delivery issue.

It will eventually restart. It has good spark and compression. I havent been able to get to the primer bulb fast enough, my pontoon has a full deck on the back and its covered, so lifting the rear deck and getting to it before it stalls is almost impossible. I dont think I have bad gas, I dont see any clouds in it. Carbs have been cleaned recently but to what extent im not sure. I think its either my fuel pump or may be as simple as a fuel filter? I just bought this boat as a project, motor as well, im going thru it to make sure its right and this is the last thing.

 

[djdarren]

Re: 79 Johnson 55hp, Possible fuel system delivery issue.

Also, when I give it more throttle approx 1/2-3/4, it will only last for a minute or two, then its up and down and then just dies. I should have said that in the beginning.

 

[Daviet]

Re: 79 Johnson 55hp, Possible fuel system delivery issue.

Is it surging really fast, thinking ign propbem and a cylinder jumping in and out or does it kind of ease in and out, thinking fuel problem. Most likely time to over carbs, sounds kinda like high speed jets plugged. Pontoons can be hard to trouble shoot because you can't get to the engine. Might have to do process of elimation, easiest and cheapest first, carb overhaul.

 

[djdarren]

Re: 79 Johnson 55hp, Possible fuel system delivery issue.

I think I found the problem last night. On the throttle lever attached to the motor ( dont know a better description ) when its sitting at idle it starts and runs fine but still wont idle......now when you use the lever for warm idle or throttle when ur sitting at the dock then put the lever all the way back down that lever attached to the motor will not go back to idle position, it stays in warm idle position which advances the timing and when I try to restart it it will not. Now when i manually push it back to idle position it fires right up??? To what I can see there is no springs missing. I am gonna check evinrudes website for a diagram to see if there is one.