Narrowing down the issue

FowlMinded

Cadet
Joined
Jul 29, 2020
Messages
14
Random question.....

in frustration of it keep giving out I unbolted the fuel pump, primed the motor, then once it cranked I removed the fuel pump. Theoretically there should be fuel pumping out of the outlet hose correct?
 

MrMarty51

Seaman
Joined
Aug 4, 2020
Messages
51
One way to adjust the carbs is to use a piece of old radiator hose and hold it to Your ear and hold the other end down close to the carb, when they all sound about the same then they are close.
I dont know about the fuel pump continuing to pump once removed from the engine. I guess that would depend of it is actuated off of the vacuum created within the crank case or if it is mechanically operated.
 

MrMarty51

Seaman
Joined
Aug 4, 2020
Messages
51
I dont know if there is a way to test to make sure there is enough crank case force to activate the pump diaphragms. Possibly a low pressure fuel pump vacuum gauge, they usually have a vacuum and pressure gauge on the same dial.
also, possibly bad check valves in the fuel pump.
 

FowlMinded

Cadet
Joined
Jul 29, 2020
Messages
14
I replaced the guts in the fuel pump so I know they are good. Next step im going to turn the motor over with the pulse line removed and feel for pressure coming from the crankshaft. If I have good pressure im going to bite the bullet and buy a new pump
 

FowlMinded

Cadet
Joined
Jul 29, 2020
Messages
14
Update:

for those following along who might have had a similar issue, I’ve fixed the problem!!!

after rebuilding the fuel pump and reinstalling, and seeing that I wasn’t getting anything out of the pump even rebuilt I started wondering why is that, everything was hooked up but nothing. Not even air! So I bought a new pump, put it on and fired up the motor. Noticing it still wasn’t sounding right I dug deeper and was looking at all my lines....where I found...... my pulse line was installed at a horrible angle (mind you I hooked everything up just the way it was with no adjustments) and there was a kink in the pulse line. Therefor the air was not getting to the pump properly for it to run. With the previous pump being aftermarket junk, I imagine the strain just caused it to rip apart (even warped).

so with the pulse line positioned correctly, a new fuel pump, a whole lot of other new things, and a giant headache and sigh of relief....the 90 HP Johnson is back up and running


thank you to all who chimed in and helped trouble shoot it!!

i will end with this....it’s important to know how each part functions in order to cut down on headaches
 

ahicks

Captain
Joined
Sep 16, 2013
Messages
3,957
Nice job staying with it/troubleshooting, - AND - getting back with us to let everyone know what you found.
 
Top