Fuel Pump Diaphram

[Jimmy_Blue]

It's a 1990 90 hp Force. I went and changed my fuel pump diaphram and now the Engine has no fuel coming out of the fuel pump to the carbs and I'm thinking I re-assembled it incorrectly. My manual doesn't even show the spring and the cap that goes on top of the spring so here's my question. Should the spring and cap go on the engine side of the diaphram or on the check valve side of the diaphram? I re-aseembled it on the check valve side of the diaphram.

 

[eurolarva]

Re: Fuel Pump Diaphram

Does this help

 

[Jimmy_Blue]

Re: Fuel Pump Diaphram

Yes that does thank you. So why would I not be getting fuel on the output side of the pump with my new diaphram but my old one I did?

 

[Frank Acampora]

Re: Fuel Pump Diaphram

Check gasker #4 and gasket #7 in the diagram. If either is leaking you won't pump fuel.

You did replace gasket #7 with a new one, didn't you?

And did you replace the hose to the nipple on part #6?

 

[Jimmy_Blue]

Re: Fuel Pump Diaphram

I replaced all gaskets for the pump. I didn't replace the hose so I'll stop by a parts store and pick up some asap. Should I try to put the old diaphram on and see if it starts? There was nothing wrong with the old one but since I took it apart I went ahead and replaced it.

 

[Frank Acampora]

Re: Fuel Pump Diaphram

Did you prime the pump and carbs with the fuel bulb? These diaphragm pumps do not have the pressure or volume to prime themselves when dry and cranking.

Do not put the old parts back in unless there is an obvious problem like a tear or hole in the new diaphragm. Very unlikely to have a damaged new one, but hey! Stranger things have happened.

 

[Jimmy_Blue]

Re: Fuel Pump Diaphram

Even after changing the diaphram the bulb was still pretty stiff so I only pumped it maybe once or twice total. We were choking it and trying to start it just like out of my force owners manual. After it hasn't run for a while should the bulb still be pretty hard?

 

[Frank Acampora]

Re: Fuel Pump Diaphram

It takes 7 or 8 good squeezes to fill carbs. Your bulb is getting old and hard--time to replace it. You can get a fuel line and bulb for about 10 bucks in Wal Mart If your local one has the boat section.

 

[Jimmy_Blue]

Re: Fuel Pump Diaphram

Ok so I'll replaced the line on the pump and change the bulb. Make sure to pump it 7 to 8 times before attempting to start and I"ll get back with you asap probably this weekend though working 12 hour days right now. One last questions. So basically your bulb does all your priming until the engine starts than your fuel pump takes over?

 

[Frank Acampora]

Re: Fuel Pump Diaphram

You got it!

 

[Jimmy_Blue]

Re: Fuel Pump Diaphram

Well after taking care of the things you said Frank it starts and runs with plenty of water coming out the 2 holes that look like exhaust and out of the exhaust snout. Only weird thing is when I have the throttle in neutral and I move it to high idle I'm getting no rpm change it seems at least sound wise cause I don't have a RPM Gauge.

 

[bman1bpm]

Re: Fuel Pump Diaphram

its a slight increase, on mine when I go from fast idle back to the regular neutral position though you can hear is slow down.