primerbulb

[brian3127]

i was running my boat in a barrel today and at idle it started to spit and sputter so i quick went back to the primmer bulb and squeezed it i was able to squeezeit about half way down. it didt really help the motor run better but i was able to squeeze it half way and i did that acoulpe times. then i was able to squeeze it all the way. then i felt the gass go through the hose. would that be bad primer bulb and hoses or would that be the gas pump.

 

[jtexas]

Re: primerbulb

what motor is it?

What effect did your bulb-squeezing have on engine performance?
Did it stop sputtering and start running smoothly on its own?

The line is supposed to have pressure in it while it's running.

If the carb float valves are closed, you won't be able to squeeze it down all the way. Only two reasons for the float valves to be closed: 1 - they are full at the moment, or 2 - they are stuck.

If they're sticking shut, then a carb rebuild with new kits is in order.

 

[brian3127]

Re: primerbulb

1975 40 johnson. it really didnt make a difference squeezing it while it was running rough. but i thought you shouldnt be able to squeeze it at all. i can squeeze it about half way. i put new plugs in it and it seems to be running better but it still stalls out. the plugs that were in there were not the right one i was at the boat shop getting a rebuild kit for the carb and asked about the plugs and theygave me the correct ones for the boat. that seemed to help. it didnt missfire it just stalled out.

 

[jtexas]

Re: primerbulb

the float valve closes off when the bowl is full, then open as needed to take in more fuel as the engine sucks it out, and whenever the valve is open the bulb is squeezable. I wouldn't expect it to get plumb hard while the engine's running but I guess it could happen.

If the float valve sticks shut, obviously the motor starves for fuel. If it doesn't close completely, gas seeps through and floods the motor. Either way, your carb rebuild kit will fix it.

Generally when the pump starts to go, you can make the engine run by pumping the primer bulb.

After it stalls out, is the bulb still firm?
If not, see if you can detect the sound of sucking air at the fittings while you pump it back up, or if you can find any fuel leaks anywhere on the engine. The bulb and fittings do wear out after awhile.

 

[brian3127]

Re: primerbulb

the bulb seems to be softer when it stalls out but i cant squeeze it all the way down. i think im going to buy a new bulb and connector to the motor and tank just to make sur that isnt it. i want to reroute it anyway. i dont like where it is routed. im going to drill a new hole in the splashwell area. so it doesnt go all the way acroos the deck and then come back to the motor so i would be taking about 2 foot off the lenght of the hose. the hose is about 7 foot long. i should be able to get it down to about 4 to 5 foot. would that help too the hose being shorter?

i have a 6 gallon metal tank and it has a slight leak. it stops when i take the cap off and release the pressure. could that be a problem too?

 

[jtexas]

Re: primerbulb

You mean pressure that built up in there during storage or transport? nah, that's not going to affect the way it runs. Length of the hose won't, either. Getting it out from underfoot, that right there might help some, though...

Shouldn't be any pressure build-up in the tank while the motor's running -- the vent has to be open.

 

[Rick.]

Re: primerbulb

When your motor is running the primer bulb really serves no purpose other than a fuel line. It should not be under pressure when the motor runs as gas is being sucked by the fuel pump. The primary purpose of the bulb is to act as the fuel pump when the motor is not running so that you get a carb. full af gas and the motor is ready to start. When running in a barrel, elevate your fuel tank to the approx. level it would be, in relation to the motor, on your boat. That way the pump doesn't have to work as hard. Rick.

 

[brian3127]

Re: primerbulb

the pressure is there from just sitting. i dont think there is a vent on it. other than maybe the cap.

 

[brian3127]

Re: primerbulb

bump

 

[jtexas]

Re: primerbulb

Just to clarify the apparent discrepancy between myself & Rick (about pressure on the bulb), after you shut the engine off, the line is still pressurized -- it doesn't actually loose pressure while the motor's running, and I've typically been able to feel some pressure on the bulb. But I agree with Rick, the bulb is just part of the fuel line while its running. Getting plumb hard while running, as described in the original post, probably means your float valve is shut at that moment, and my suspicion is, that the valve is stuck. Just don't know for sure.

The vent on the gas cap has to be open while the motor's running, so air can enter as fuel is sucked up by the motor. Otherwise, the pump has to pull against a vacuum, which it's not designed to do.

 

[Fl_Richard]

Re: primerbulb

Take the gas cap off the tank and see how it runs. If it doesnt stall then the tank needs to be vented.

 

[brian3127]

Re: primerbulb

i figured why it wouldnt idle for very long one of the holes were blocked or pluged that let the gas into the trought of the carb. im going to cleanit better. it was part of the old fiber washer for the low speed nedle valve. should the connectors fit tight with no gaps the connector at the motor fits tight no gap but the one at the tank has about a 1/8 in. gap.

 

[jtexas]

Re: primerbulb

connectors usually appear butted up flush against each other but that part of it isn't sealed. if that spring-loaded clasp is hooked over the notch there, and if fuel's not getting out nor air's getting in, it's good to go. If you have to pump the primer bulb again before restarting the motor, that would be one place to look for the cause.

 

[brian3127]

Re: primerbulb

it was the carb. i cleaned it more after pulling the fibers out of the holes. put it back on the motor. started right up and kept running. so i made some adjustments. the motor idles good and switches gears good.