primer bulb

The primer bulb on my 2000 90 2 stroke mer is not keeping a prime. engine will stall when i pump the bulb and rebuild prime it runs fine, 40 plus mph. What do you think? replace the bulb? fuel fitler? clogged lline?
thanks,
d

Re: primer bulb

It sounds like the bulb or line is leaking pressure from a hole or something. I would replace the bulb and line and see what you get....if the line was clogged it would increase pleasure behind the clog and wouldn't run well at high RPM because the clog would diminish gas flow....If the line in leaking pressure due to a hole or something you may not get gas leaking out but when the engine is running low RPM it wont hold the PSI needed to keep the gas flowing.

If you can do a pressure test on the line and bulb it will help to see if that is the issue before spending money.

Search the forum for pressure test, I beleive there is one that explains how to do it.

good luck.

Re: primer bulb

A poor O-ring seal in a fuel hose fitting may allow a small amount of air to leak into the line, at low speeds the motor can act like it is running out of fuel.

Temporarily install a clear hose between the fuel pump and carb so you may watch for any air bubbles in the fuel, indicating air leaking.

Check ALL hose fittings, clamps and hoses, until you cure the leak.

Be sure to remove the clear hose once finish, it is NOT recommended fuel line and should only be used for testing.

Re: primer bulb

The man says the engine will "stall" when he pumps the primer bulb. That means one or more of the carbs has a leaky inlet needle and seat which allows way too much fuel into the engine and hence it stalls. That is also why the primer bulb will not firm up. If the needle and seat in each carb are functioning properly, the primer bulb should firm up with the engine off. If there are leaks after the bulb, fuel would squirt out. If there were an air leak before the bulb it would have to be significant and in that case, it would not be possible to stall the engine by pumping the bulb. Next -- there is no pressure in the fuel line or primer bulb once the engine starts. Remember -- fuel is "sucked" through the line and is not forced to the engine under pressure once the engine starts. The whole purpose of the primer bulb is simply to fill the carb float bowls.

Re: primer bulb

the bulb will tighten up when i'm starting the engine, however when I get around 4000 rpm it's like the engine bogges down and the primer bulb is loose, does not stay tight. I had the boat out for about 6 hours on wednesday and it did it starting out stalling at 4000 rpm right off the start, i had my buddy pump the bulb until we got out of the inlet and then opened her up again and then she did fine. Once we were about 10 miles out it start it again so I trolled around for about 1 hour at around 5 mph and then shut off engine to bottom fish for about an hour. When I started it back up it ran like a champ 5200 rpm going about 41 mph. This of course was on the way back into the boat landing.
thanks,

Re: primer bulb

When the motor is running it is normal for the bulb to get soft as there is fuel running thru it. Check all your lines for cracks (especially the primer bulb) or loose clamps. Replace as necessary. If all is good rebuild your fuel pump.