50hp possible bad fuel pump? Help me help a neighbor.

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Brokenrod

Seaman
Joined
Nov 29, 2009
Messages
64
Hi all,
I'm trying to help out a neighbor of mine. He has a 1987 Johnson 50hp, model no. TL50CUD. The primer bulb will go soft when the engine is running, but with the engine off, the bulb stays hard as a rock. The fuel filter is clear, so you can visibly see the fuel level go down. He was having some no start issues until he cycled the choke solenoid?( starboard side of engine, with the red switch thingy) He moved the red switch back and forth a few times and heard a click( The switch originally was, and still is in the automatic start position). The motor starts right up every time now, but still have the issue with the bulb going soft. We have checked all the lines for signs of air or fluid leakage, but so far found nothing. Does this sound like a fuel pump rebuild kit is in order?
I went to the local library today and checked out a manual, but it was pretty vague. Basically only showing a pic of the fuel pump, and barely any reference to the choke solenoid.( if thats even what its called.)
I am free to receive any troubleshooting tricks and tips to narrow this down for him. Help me help a good neighbor!
Thanks,
Brokenrod
 
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hidef

Lieutenant
Joined
Aug 22, 2009
Messages
1,465
Re: 50hp possible bad fuel pump? Help me help a neighbor.

That engine uses an electric fuel primer. It dumps raw fuel down the intake manual when you push the key in. The primer bulb won't stay rock hard when the engine is running but it should be full of fuel. A rock hard fuel primer is a good indication that there are no fuel leaks from the primer bulb to the carb and the needle valve and float are working correctly. Does the engine run okay out on the water or does it die if you don't keep pumping the primer bulb? If it runs at all speeds with no surging I would say it is fine if you have to keep squeezing the primer bulb to keep it running you have an issue with the fuel pump and it needs to be rebuilt or replaced. If you are going to rebuild the pump now would be a good time to replace all the fuel lines with alcohol resistant ones and also clean the carbs.
 
B

Brokenrod

Seaman
Joined
Nov 29, 2009
Messages
64
Re: 50hp possible bad fuel pump? Help me help a neighbor.

He hasn't run it on the water yet. only on the muffs. The motor will die if he doesn't pump the bulb up when the fuel filter drains. Another question is- Why would he go from a no start situation to starting right up after cycling that switch and hearing the solenoid click? could it have been stuck or gummed up?
 
B

Brokenrod

Seaman
Joined
Nov 29, 2009
Messages
64
Re: 50hp possible bad fuel pump? Help me help a neighbor.

Thanks for the help hidef! I checked your link, but he has the VRO system fuel pump. I'll forward this info to him and see if he wants to rebuild or replace. Thanks again.
 
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Haffiman

Commander
Joined
Dec 17, 2009
Messages
2,454
Re: 50hp possible bad fuel pump? Help me help a neighbor.

The 'click' he heard was from the fuel pump.
When he opened the primer valve, the fuel pump pressure was released and the air membrane retracted due to the spring pressure.
All an indication that the pump works!!
If the pump had NOT been working, the air pump membrane spring would not have been compressed!
Further you mention that the fuel in the filter gets lower - the pump is working pumping the fuel OUT of the filter!!
As a conclusion I would say that somewhere between the filter (might be the filter itself) and the bulb it is an air leak.
Pump suck air and not fuel!!
If he on top of all still has the VRO connected, every time the pump 'clicks', it sucks OIL and AIR and filling the carburetors with mainly oil!!
Engine does not run on oil alone!
It may however start with activating the primer solenoid as that sprays fuel WITHOUT oil directly into the intake. As soon as that is burned, back to attempting sucking oil from the carburetors which does not work!!
Find and fix the air leak.(hose connector?)
Drain the carburetors (drain plug)
Pump in new fuel in the system and start!!
 
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