Have to keep pumping primer bulb..

[*WEAVER*]

My outboard has been running bad for awhile and I could not figure out the problem. It seems like a fuel starvation problem, whenever I would finally get the motor running, if you gave it just the slightest bit of a throttle blip, it would die, or have a sucking sound to it and kind of stumble.

I've rebuilt the fuel pump, and still have the problem. Tonight, I started it, it was doing the same thing, so I kept pumping the primer bulb, and the motor would run like it's suppose to with good throttle.

Does it sound like the fuel pump is still not working right? Possibly a carb situation? I've about run out of things lol. Thanks

 

[achris]

Re: Have to keep pumping primer bulb..

My outboard ....

Which is a ________ (model and serial number would be best)....

 

[*WEAVER*]

Re: Have to keep pumping primer bulb..

Mercury 1990, 90 horse. Serial #OB194836

 

[saumon]

Re: Have to keep pumping primer bulb..

I'd start by try running it on a portable new tank with a new/known good fuel line and bulb.

It has the advantage of eliminating half of the possible causes: if it run good with the portable tank the problem is somewhere in your fuel line/connector/primer bulb/tank pickup. If the problem is still there it's most likely carbs/pump related.

 

[achris]

Re: Have to keep pumping primer bulb..

With the engine not running, give the primer a really good squeeze and look for fuel leaks... If you get them, they're air leaks when the engine is running. That would account for the symptoms you've got.

Chris.......

 

[j_martin]

Re: Have to keep pumping primer bulb..

With the engine not running, give the primer a really good squeeze and look for fuel leaks... If you get them, they're air leaks when the engine is running. That would account for the symptoms you've got.

Chris.......

Bear in mind that a white knuckle grip on the primer bulb will overpower the needle valves in the carbs, and spill some fuel there. That would be perfectly normal.

A leak anywhere else, however, could be the problem

And yes, you could have fuddled up the fuel pump rebuild. It also could be a simple as a loose fuel hose clamp on the fuel pump. The squeeze-leak test should find it.

hope it helps
john

 

[saumon]

Re: Have to keep pumping primer bulb..

And yes, you could have fuddled up the fuel pump rebuild.

Something similar happened to me a few years ago, before i understand the importance of having an EOM service manual and following the exact procedures and torquing specs.

I've serviced my fuel pump (diaphragm kit) but it doesn't fix the problem (bogging down). After a lot of head scratching, i finally found out that, when reinstalling the pump cover, i torqued the bolts way too much, causing the cover, wich is made of plastic, to bend and allowing air to enter.

 

[ClassyGlassy]

Re: Have to keep pumping primer bulb..

I had the EXACT problem on my '72 Invader and it was the fuel line connections to the tank and the engine, both male and female quick disconnects!

I ended up replacing all connections, fuel line, and primer bulb before it finally picked up and ran correctly......the fuel line connectors were last to be replaced

It doesn't cost very much to get the proper OEM Fuel line and Primer Bulb as well as replacement male and female connections.