Motor won't run at WOT

[Tuner]

I have a 1979 Johnson, 35 HP. Model 35EL79A. It has been running perfectly until last week. It starts normal, runs normal at idle, slow, and about half throttle. When I go to full throttle, it comes up to speed normally but after about 30 seconds the engine slows and will die if I do not reduce throttle. If it dies, it will restart with slightly more than normal cranking. If I reduce throttle before it dies, after a short period of running at part throttle, I can go back to full throttle but only for about 30 seconds.

I took the fuel tank cap off to make sure the tank was getting air and it had no effect. I have checked the fuel filter and it was clean (only a few specks) and I have disassembled the fuel pump and can not find any problems. I have inspected the fuel hose from tank to engine and do not see any cracks. This is the first time using the motor after getting a new tank of fuel. I mixed the oil myself. This fuel came from the same gas station as the previous tank of fuel. This tank of fuel is high test, the previous tank was regular.

Help???

 

[Windykid]

Re: Motor won't run at WOT

Have you tried pumping the ball when this happens?

 

[Tuner]

Re: Motor won't run at WOT

I tried pumping the ball but it seemed to have no effect.

 

[Rudy Brown]

Re: Motor won't run at WOT

I had a boat that did the same thing once. Found out It had sucked a piece of celofane up to the fuel pick-up. Took me 6 months to figure that one out.

 

[Windykid]

Re: Motor won't run at WOT

I would look into rebuilding the fuel pump.

 

[tashasdaddy]

Re: Motor won't run at WOT

is this a new plastic tank. they been known to have plastic pieces, in them from threading the fittings, and the mfg. process. could be the pickup it partially clogged, and not getting enough fuel at hig speed. also is the bulb collasping. is the vent open on the tank. new plastic one have vent in the fill cap that needs to be opened.

 

[tashasdaddy]

Re: Motor won't run at WOT

also Tom change your screen name. email address can be bad. junk mail, phishing expeditions, spy ware.

 

[Tuner]

Re: Motor won't run at WOT

I have changed the screen name. I don't know how my address got used as the screen name in the first place. Thanks.

I don't know the age of the tank but it is not new. It does have a vent in the filler cap and the vent was open. I even loosened the cap to make sure the tank was getting air but that did not help. I did not notice if the bulb was collasped, that is a good tip.

I have not yet removed the pick up tube from the tank, that will be my next attempt.

I don't want to rebuild/replace the fuel pump yet because I don't think that is the problem and after disassembly, I could not find anything wrong with it. The pump is a fairly simple device and a replacement is over $60.

Is is possible to be sucking air at the snap on fittings of the fuel line?

Maybe I will just have to drive slow till we get it figured out.

 

[tashasdaddy]

Re: Motor won't run at WOT

could be sucking air, pump rebuild kit $15.95 + shipping here http://www.laingsoutboards.com/newp...ncludes Gale, Sea King up to 1963, and others