Fuel pump sanity check needed, please

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lugoismad

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1983 25HP Johnson.

It'll fire up, and run. Idle for about a minute and then act like its running out of gas, and then die.

If I take it above idle, it'll die even faster.

Fuel squeezy bulb will still be moderately stiff.

I took the fuel line off the fuel pump where it goes to the carb, and put on a line that dumped into a can. Started it up and it idled on the fuel on the carb for about 30 seconds. No fuel came out of the pump.

This would indicate a bad fuel pump, correct?

Just want to make sure before I tear into this thing.
 
If after taking the line off the pump going to the carb, did you squeeze the primer bulb to prime the pump? There should be fuel coming out of the line coming from the pump going into your can. The primer bulb should not get hard with that line disconnected. The bulb gets hard whet the the float inside the carb bowl raises and closes the needle valve supplying fuel to the bowl. If your jets inside the carb are plugged too bad it may idle for a few seconds also on the fuel pumped into the throat of the carb by the primer bulb. The primer bulb will supply more pressure than the pump will and can send a little fuel into the throat of the carb than the pump could.
 
LOL you are not "tearing into it" . . . it is a very simple and often performed
bit of maintenance. Just order a fuel pump repair kit $15 on E-Bay.
which consists of a couple of gaskets and a new diaphragm.
On mine, there was a very very small pin hole in the diaphragm that you could
only see if you held it up to the sun.
For now, at least take the pump apart and inspect it. If the diaphragm is stiff and hard, it needs
to be replaced anyway. It is not necessary to put any sealants on the gaskets to put it back together or the new one.
There are still several other conditions that could cause this issue.
Loose clamps, quick disconnect sucking air at the motor connection,
the infamous float setting in the carb, yada yada yada.
K.Mixon::: The primer bulb should not get hard with that line disconnected. Fuel should easily flow through it.
THEN, crank the motor and the fuel should shoot out about 3 feet from the motor.
so be careful not to have the line pointed at your face or body or else you could be doing the Richard Prior 2-Step.
you are not "replacing" the fuel pump, just replacing the soft goods.
and while you have the pump apart, sand down both mating surfaces so they are nice and flat.
maintenance is all it is.
 
Barefoot_Johnny said:
LOL you are not "tearing into it" . . . it is a very simple and often performed
bit of maintenance. Just order a fuel pump repair kit $15 on E-Bay.
which consists of a couple of gaskets and a new diaphragm.
On mine, there was a very very small pin hole in the diaphragm that you could
only see if you held it up to the sun.
For now, at least take the pump apart and inspect it. If the diaphragm is stiff and hard, it needs
to be replaced anyway. It is not necessary to put any sealants on the gaskets to put it back together or the new one.
There are still several other conditions that could cause this issue.
Loose clamps, quick disconnect sucking air at the motor connection,
the infamous float setting in the carb, yada yada yada.
K.Mixon::: The primer bulb should not get hard with that line disconnected. Fuel should easily flow through it.
THEN, crank the motor and the fuel should shoot out about 3 feet from the motor.
so be careful not to have the line pointed at your face or body or else you could be doing the Richard Prior 2-Step.
you are not "replacing" the fuel pump, just replacing the soft goods.
and while you have the pump apart, sand down both mating surfaces so they are nice and flat.
maintenance is all it is.
Click to expand...

Thanks Johnny!

Do you know of a good howto for this?

I'll be honest, I can work on big mechanical stuff. But I'm a big guy and I have big hands, and dealing with small delicate things like these gaskets is something I'm afraid of.

I have the rebuild kit sitting on my desk right now. :mrgreen:
 
sure, no problem . . . Gather around boys n gurls, it's story time.

Fuel Pump Tutorial

1. remove screws holding pump to motor.
2. remove black plastic piece, toss out gasket, DO NOT toss out the wire screen. (rough edge point out).
3. put wire screen back the same way it came out.
3. throw away the old gaskets
- personally, I like to sand down the two mating surfaces just to make sure there is a good seal.
4. put in new gaskets
5. put the screws back, fasten to motor
- I think there is a special position to put in the gasket under the black plastic piece.
- also, the hose fitting has to go in a certain position. Check your manual. (you DO have a manual, right ?)
6. start your motor
7. if it runs okay, that was the problem - go fishing.
8. if it does not run okay, troubleshoot entire fuel system from the tank back to the motor.

should take all of 5 minutes to do the gasket kit the first time you do it.
Next year, do it again. Should take you 3 minutes.
it is MAINTENANCE
ETHANOL REAKS HAVOC ON RUBBER STUFF





.
 
Barefoot_Johnny said:
sure, no problem . . . Gather around boys n gurls, it's story time.

Fuel Pump Tutorial

1. remove two screws
2. remove plastic piece, toss out gasket, DO NOT toss out the wire screen.
3. put wire screen back the same way it came out.
3. throw away the old gaskets
- personally, I like to sand down the two mating surfaces just to make sure there is a good seal.
4. put in new gaskets
5. put two screws back, fasten to motor
6. start your motor
7. if it runs okay, that was the problem - go fishing.
8. if it does not run okay, troubleshoot entire fuel system from the tank to the motor.

should take all of 5 minutes the first time you do it.
Next year, do it again. Should take you 3 minutes.
it is MAINTENANCE






.
Click to expand...

I found this howto and it kinda scared me. Looks rather complicated.

https://www.leeroysramblings.com/Rebuilding_fuelpump.htm
 
I just gave my boat to my brother that has the 25 Johnson on it,
So I can't run out and check it for certain. I have probably changed
the gaskets a dozen times since I have had it from 1975.

but, your pump should look like this one.
pump.JPG
it is vacuum operated. no springs to pop out.
take it off, take it to your kitchen table, put down news paper,
open it up slowly, check it all out, clean it up, put in new gaskets.





.
 

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