1984 8hp Fuel Pump Rebuild

[Chavi]

Hi everyone,

My buddy has a 1984 Johnson 8hp that is giving him problems. It quit running one day at the lake and would not start. I checked the spark and determined that it was good. I then removed the fuel line coming out of the fuel pump and started pulling the pull cord to start the engine. I noticed that the fuel pump was extremely weak. I then poured some fuel into the carb and it started after three or four pulls so that made me think that the fuel pump was shot. I looked up the fuel pump rebuilt kit (393088 or 18-7823) and saw that it was less than twenty dollars but when I saw all the parts it came with, it made me think that it is going to be a pain in the butt to rebuild.

Has anyone rebuilt a fuel pump on an engine similar to the one I will be working on? If so, please let me know if you think it will be better to just try to buy the fuel pump brand new. I am trying to save my buddy some cash by DIY since we live in an area that doesn't have any outboard engine mechanics. I have rebuilt the fuel pumps on my 2005 Yamaha 115hp and my 1982 Mercury 40hp with out any problems but they did not have as many diaphragms and springs as the Johnson. Any help will be appreciated.

Have a good day and keep boating.
Chavi.

 

[Vic.S]

Are the instructions on LeeRoy's Ramblings website any help ?

http://www.leeroysramblings.com/Rebuilding_fuelpump.htm


Loads more on LeeRoy's site you might find useful

http://www.leeroysramblings.com/OMC 6-8hp.htm

.

 

[BatDaddy1887]

I rebuilt my kicker motor fuel pump last year on a Mariner 8, as well as cleaned the carb. Simple stuff, with the manual. It is recommended to let the motor run out of fuel when not using for more than several weeks as the fuel can gum up the works, even with stabilizer in the fuel. Use Seafoam in every 3rd tankful or so to keep the system clean. One more thing, it might be a good idea to put a fuel filter inline from the tank to the engine, and have a spare in your on-board kit.

 

[Bullie]

Chavi,
I have rebuilt one and while it was a pain with the tiny parts it isn't that bad if you enjoy this sort of thing. You have to follow the directions PERFECTLY or it will not work. Take good pictures of the orientation of the fuel inlet and outlet and the tabs and it shouldn't be too bad.

I used the link Vic supplied to you as my information resource.

 

[slate1234]

I did one last weekend, I found drawing a line across the fuel pump useing a white marker pen helps when realigning with new parts, also pay attention to where the small springs come from, I did get a full set of instrctions with the rebuild kit I had

 

[racerone]

Factory kit comes with instructions.---All you really need in most cases is a new diaphragm and make sure the check valves are clean.-----Diaphragm is available by itself.

 

[Chavi]

Thanks for everyone's responses. I finally had time to try to figure this out. I researched a little more and discovered that there is actually a filter in the fuel pump housing itself. After I found it I decided to check it before ordering the rebuilt kit. I took it apart and realized that it was clean and nothing was preventing the flow at the filter however I did notice that the filter gasket was warped so I turned it over and faced it the opposite direction and it worked great. I think in the future it will definitely need the rebuilt kit though.

Thanks again for everyone's assistance.
Chavi