72' merc 9.8 fuel pump question

[junior1113]

if i pump ball all day it runs fine. if i stop it will soon stall and prime ball will be empty. went to rebuild and noticed it pumps gas by the compression of the motor. what to replace. thanks-paul

 

[wtwe2step]

Re: 72' merc 9.8 fuel pump question

Not sure about your exact application or if it even has a fuel pump as I know them but a michancial fuel pump uses a vacuum pulse from the compression of the engine to drive a diaphram in the fuel pump. The pulse is supplied by a hose and inside the fuel pump there are two valves that control flow along with the diaphram. The pulse hose could have a leak or the valves in the fuel pump could be wasted or the diapham could be wasted. Check the hose and if ok breakdown the fuel pump and rebuild.

 

[green4themoney]

Re: 72' merc 9.8 fuel pump question

yeah you should rebuild your fuel pump, part number 21-30430A2
http://www.eastcoastmarineservice.com/fuelsys.html#fpkit

 

[d.boat]

Re: 72' merc 9.8 fuel pump question

yea, order a rebuild kit, cheap and very simple. You can probably find one locally, they're fairly common in my experience.