fuel pump diaphram

[icedogs66]

1978 merc 800 (80 hp) rebuilt all fuel related parts (pump carbs and lines) after doing this I found that I coudnt get pressure to build in the primer bulb I replaced it and had the same problem. I pulled the fuel pump off and found that there was fuel on both sides of the diaphram is this normal? Or is the diaphram shot?

 

[jebeebe]

Re: fuel pump diaphram

shot.............................need a rebuild kit.

 

[icedogs66]

Re: fuel pump diaphram

thanks thats what I thought but best to be sure.

 

[jebeebe]

Re: fuel pump diaphram

thanks thats what I thought but best to be sure.

You said you rebuilt the pump? Maybe you didn't get it back together right. There should only be fuel on one side of the diaphram. I believe the other side recieves pulses from the crankcase Wich does the pumping. If your bulb doesn't pump up it is probably pumping gas into the crank case through the diaphram. I rebuilt mine and had a little problem figuring out the procedure..............Jerry

 

[icedogs66]

Re: fuel pump diaphram

yes it was rebuilt only lasted one outing is there anything special I should doing when putting it back together. I also did the carbs and think I might have set the floats wrong which in turn wont allow fuel into the bowl which might blow out the diaphram? Maybe?

 

[ricksrster]

Re: fuel pump diaphram

Make sure the surfaces where the gaskets contact the block and the pump housing are really clean and tighten housing down evenly.