73 Johnson 25 fuel issue

Cwjackson20

Recruit
Joined
Apr 14, 2020
Messages
2
I’ve got a 73 Johnson 25 horse that I can’t keep running. I’ve replaced all fuel lines. Brand new Johnson fuel pump new tank and new fuel line from tank to fuel pump. With the fuel tank sitting at normal height it will run for maybe 2 mins then start sputtering and die. With the tank level with motor or higher it will sit and idle all day long. Any ideas on what it could be?
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,890
Trouble shooting required.-----First a compression test.----Then test run with another tank and hose.----Possible air leak.
 

Crosbyman

Vice Admiral
Joined
Nov 5, 2006
Messages
5,811
you did put the gasket between the pump and frame….
did you do a blow test on the pump before installing OUT>>>>>IN no air passes
vent open…. and working (run with the cap off the tank as a test)
 

Cwjackson20

Recruit
Joined
Apr 14, 2020
Messages
2
Compression test is 115 on top 105 on bottom and yes replaced gasket behind the pump. How do you do the blow test?
 
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