63 75 hp johnson-no fuel pressure

[louonwallum]

trouble priming fuel bowl. finally get the bowl to fill, motor starts then quits.fuel bowl empty. pumping bulb again i see some gas in the top of the carb and can hear air, but motor will not start . i checked the gasket in the bowl and it looked pretty thin and worn. made a new one while waiting for a replacement and at first got the bowl to fill easily. now the problem i just described. i have the kit to rebuild the fuel pump, but is the pronlem elsewhere? the motor has good compression. any thoughts?

 

[2manband]

Re: 63 75 hp johnson-no fuel pressure

Sounds like it could be a fuel pump to me. Can you keep the motor running if you keep squeezing the primer bulb?

 

[louonwallum]

Re: 63 75 hp johnson-no fuel pressure

Sounds like it could be a fuel pump to me. Can you keep the motor running if you keep squeezing the primer bulb?

no, that dosen't seem to work

 

[2manband]

Re: 63 75 hp johnson-no fuel pressure

no, that dosen't seem to work

Would you be able to try with a different fuel hose/primer bulb? One that you know to be good?

 

[louonwallum]

Re: 63 75 hp johnson-no fuel pressure

Would you be able to try with a different fuel hose/primer bulb? One that you know to be good?

i did try with a brand new unit, same results. like i said, i was able to prime the bowl, but motor quits immediately. one thing i need to do after seeing another blog, is pet the throttle lever further back. right now it's almost in line withe the shift lever. if that solves the problem then i will dope slap myself.

 

[louonwallum]

Re: 63 75 hp johnson-no fuel pressure

update. just rebuilt the fuel pump and viola! plenty of fuel pressure. but...engine ran for a few seconds and quit. this time fuel bowl full. started again and died. pulled the plugs and found they were pretty wet so gas is getting there any way but after cleaning them same thing. starts and wont stay running. carburator problem?

 

[yorab]

Re: 63 75 hp johnson-no fuel pressure

Start with the basics. What is the history of the motor? Has the carb been cleaned since 1963? Are you getting spark at all cylinders? Use a spark tester to see if spark jumps a 7/16" gap. Then post back.

 

[louonwallum]

Re: 63 75 hp johnson-no fuel pressure

thanks for your reply. since this post i changed the plugs and rebuilt the fuel pump. managed to get the engine started in the barell and ran it for +/- 10 minutes. seem to run a little rough but i'm hoping getting it up to speed in the water clears it's throught. and the carb may not have been cleaned or rebuilt. i know i probably should but i'm a little nervous about doing it. do you think running it in the lake will tell me anything?

 

[yorab]

Re: 63 75 hp johnson-no fuel pressure

Most auto parts stores sell a spark tester for about $8. You should get one in order to determine the strength of the spark.

You should definitely also change the water pump impeller if you don't know the last time that it was changed. You should do this before taking to the lake.