1988 Johnson 60 - Dies at Low Speed

[atengnr]

I was out on the lake today, ran around the lake for 30 min and then stopped to swim. Upon restart an hour later, the motor started but was running poorly, died after 30 sec. and would not re-start. I began rowing, after about 20 min I checked the primer bulb and it was nearly empty. I pumped it up and the motor started normally.

I found that if I run the engine at mid to high throttle, it runs good, but at low speed it will die after a brief time. The primer bulb seems to begin to empty at low speed. Is this symptomatic of the fuel pump going bad??

Thanks.

 

[atengnr]

Re: 1988 Johnson 60 - Dies at Low Speed

Can anyone provide a suggestion?

 

[Dennisanoka]

Re: 1988 Johnson 60 - Dies at Low Speed

Iwombat told me last week that, "When you pump the bulb does it stay hard? If not you've probably got a torn diaphragm in the pump." This had to do with a VRO. But it may be the same with the regular pump as well. Do you still use the VRO? In any case I would check for an air leak in the pulse hose if you have a vro or a loose fuel pump where it mounts to the engine if you do not have a vro. Going back further I would rule out an air leak between your fuel pump and the fuel tank.

 

[atengnr]

Re: 1988 Johnson 60 - Dies at Low Speed

Thanks for the reply. I dont use the VRO.

Also, when the motor is tilted, a bit of fuel drips from the carbs into the splashwell on the boat.

Whats odd about this issue is the engine will run all day at higher throttle, and bulb only seems to loose prime at low speed (not totally empty though).

 

[rickdb1boat]

Re: 1988 Johnson 60 - Dies at Low Speed

If you can pump the bulb and keep it running somewhat normally, then the fuel pump would be suspect. You may also want to take a look at the check valve on the pulse line. It screws into the engine block and provides vacuum to the fuel pump (VRO). Also make sure all the hoses are tight and secure, especially the one to the pulse fitting...

 

[atengnr]

Re: 1988 Johnson 60 - Dies at Low Speed

If you can pump the bulb and keep it running somewhat normally, then the fuel pump would be suspect. You may also want to take a look at the check valve on the pulse line. It screws into the engine block and provides vacuum to the fuel pump (VRO). Also make sure all the hoses are tight and secure, especially the one to the pulse fitting...

Thanks. Ill take a look. Can a fuel behave this way where its not working well enough at low speed, but is fine at high speed?

 

[rickdb1boat]

Re: 1988 Johnson 60 - Dies at Low Speed

If there's not enough crankcase vacuum at low speed because of a loose or split hose, then yes, it can affect it in that way. Check all the simple stuff first, then move to the high dollar items...

 

[coletrain6000]

Re: 1988 Johnson 60 - Dies at Low Speed

I had a similar problem with a 15hp mariner. I replaced the fuel tank and fuel line and connectors with new stuff from wal mart. I bought new universal fuel line with primer bulb, hose clamps, and fuel tank connectors. I also purchased Teflon Tape and wrapped the threads of the new connector and the output on a new atwood 6gal fuel tank. The fuel tank does not come screwed tight or sealed from the factory. I had a leak in my fuel line somewhere. The air causes improper fuel flow to the motor esp at low speed. Also make sure your fuel tank is vented. This fuel tank has a small knob on the cap that you unscrew a little for venting. Lastly, make sure your fuel is fresh. Gas has a limited shelf life.

 

[atengnr]

Re: 1988 Johnson 60 - Dies at Low Speed

Thanks, my gas tank is original - 1968, but fuel line is new. How do I check for air leaks??

 

[atengnr]

Re: 1988 Johnson 60 - Dies at Low Speed

Huh, well its running with muffs and primer bulb is NOT staying full. It did stall after about 5 min of idling, but restarted easily.

HOw do I get to the pump? Do I pull the plenum off the carbs to get to the mounting bolts??

 

[Dennisanoka]

Re: 1988 Johnson 60 - Dies at Low Speed

You might find this link helpful at least to identify the parts that you are looking for. http://www.evinrude.com/en-US/Accessories/Literature/Engine.Diagrams.htm but this is not nearly as good as a manual.

Otherwise just follow the fuel line in and the first thing you'll come to is the fuel filter then the fuel pump. Expect your fuel pump to mount directly to your engine, getting the pulse right off the manifold.

Is this a 1988 or a 1968? How should you check for leaks. I do a REAL close visual for cracks and then go thru a see if anything is not tight.

 

[Dennisanoka]

Re: 1988 Johnson 60 - Dies at Low Speed

You had said you have the original 1968 tank. Your fingers must have gotten confused because they did not make a 1968 60hp, so skip that question.

 

[atengnr]

Re: 1988 Johnson 60 - Dies at Low Speed

You had said you have the original 1968 tank. Your fingers must have gotten confused because they did not make a 1968 60hp, so skip that question.

Sorry the tank is 1968, 1988 motor was a recent install on my 1968 vintage boat.

The pick up screen in the tank is clean, as is the inside of the tank.