My vintage outboard

[25horses]

Hi
My questions concern a vintage 1969 25 hp Johnson two-stroke outboard. I have recently put in a new fuel pump item nr. 62-13-3939 bought as I assumed that had to do with my problem.

But even with a new fuel pump the motor runs poorly. I have to press the tank bulb all the time to get the thing running.

It seems like the motor does not get enough fuel anyhow although the pump is completely new. So where would you guys start looking to correct the problem?

Your ideas is very much appreciated.

Cheers
Roland

 

[racerone]

Crankcase compression pulses drive the fuel pump.----Perhaps there is an issue there.-----Why the little asterisk things in some of your words about this beautiful , simple motor?-----What other trouble shooting have you done besides saying " it must be the fuel pump " that is bad.

 

[F_R]

The slightest little leak anywhere between the fuel pump and the level of the gas in the tank will allow the pump to suck air instead of gas (air is lighter than gasoline). Maybe there was nothing wrong with the old pump?

 

[Vic.S]

Prime suspect for air leaks are the fuel line connectors .due to worn of damaged O rings.