Flat primer bulb

DWD · Apr 4, 2012

With gas turned off at tank [ built in tank ] and trailering boat to river is it normal for the bulb to go flat, would the carbs be leaking. What could cause this?

boobie · Apr 4, 2012

Re: Flat primer bulb

I don't think a carb or fuel leak could cause the bulb to go flat. You may have a bad primer bulb. It takes a good sucking on the mtr side and a good fuel restriction on the tank side to make it go flat when running.

archcycle · Apr 5, 2012

Re: Flat primer bulb

Do you mean it's actually squished flat on arrival at the river or is it just no longer full of fuel?

toddschubert · Apr 5, 2012

Re: Flat primer bulb

Restriction at the tank would be my bet. Do you have a fuel filter? did you check it?

DWD · Apr 6, 2012

Re: Flat primer bulb

I had the gas cut off at the tank because i have no luck cranking this engine when i first got to the water. It would crank up later in the morning, i was thinking it was flooding itself while trailering to the water. I was correct when i got to the water the bulb was flat i manage to get enough gas in the carbs from working with the bulb to crank the engine. That was the first time this engine has cranked up in the morning at the water in six trips.thinking i have a leaking diaphragm in fuel pump, because i turned the gas off last night at home this morning the bulb was pull almost flat with the boat under the shed. Has anyone had this kind of problem help.

boobie · Apr 6, 2012

Re: Flat primer bulb

What happens if you leave the fuel shut off valve turned on overnight??

DWD · Apr 7, 2012

Re: Flat primer bulb

I did shut the gas off at the tank last thursday night ,the next morning the bulb was almost flat.somehow fuel is getting into the engine and fouling out the plugs.i'm not using the oil injection side of the pump just the gas side, i mix my oil & gas after a 2,800.00 repair on this engine because of the vro failure.i'm wondering if the fuel could be entering the engine through the pulse limiter valve, if the diaphragm in the fuel pump is bad, somehow the fuel is being siphon out of the tank and getting into the engine.

Joe Reeves · Apr 7, 2012

Re: Flat primer bulb

The "Anti Siphon Valve" at the fuel tank is either stuck open or missing. Install a new one.

It will be the very first fitting that the fuel hose attaches to at the tank.

Silvertip · Apr 7, 2012

Re: Flat primer bulb

Think about this. You shut the valve off at night when the tank and fuel line is warm. The floats in the cabs shut off because the bowls are full. The valve is closed at the other end of the line. The bulb collapses because the cold night air causes a vacuum in the line and the bulb collapses. Leave the valve open and fix the hard starting problem if that's why you are turning off the fuel.

DWD · Apr 7, 2012

Re: Flat primer bulb

I have a lever valve at the tank that the fuel line plugs up to. I'm turning the valve off so no fuel can be pulled from the tank.if i don't turn this valve off the engine gets flooded with fuel and won't start. When it does crank it covers the boat and surrounding area with smoke from exhaust.

Joe Reeves · Apr 7, 2012

Re: Flat primer bulb

..........

toddschubert · Apr 8, 2012

Re: Flat primer bulb

What about, a stuck on primer in the engine? If it were getting juice all the time it would suck fuel wouldn't it?

Silvertip · Apr 8, 2012

Re: Flat primer bulb

Primer systems require pressure in the fuel line to operate which is why you squeeze the primer bulb on a first start of the day. These are not pumps but merely selenoid valves. It appears there is a float issue in one or more carbs because there is no way the engine should flood just sitting still. Fix that problem and you can eliminate the valve and solve the flat bulb issue at the same time. As usual, a band aid is used to mask the real problem.

Flat primer bulb

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