2008 DF115 Looses Prime

[stushmd]

I have a 2008 DF115 that runs good out of the gate. Can go however long. Stop to fish for 10 minutes -- starts and will go for less than a minute and acts like its of of gas. Primer bulb has no fuel in it. 4-5 pumps --good to go till next stop. Same thing again..... Funny thing never does it on the first go of the trip.

I have replaced;
- Tank pick up tube
- Cleaned tank vent line
- All fuel line up to fuel filter on motor (replaced thin stuff inside cowl)
- New Water Fuel separator - base and filter
- LP filter
- New LP fuel pump
- New clamps on all lines
- New Bulb

Still does it???

Can air be getting into the vst - back flowing causing lose of prime ?

Bulb is usually empty - but fills with 1-2 squeezes

My next move is to take the intake off and tear into the VST.

Any suggestions ?

Stan

[redlowrey]

I have a 2008 DF115 that runs good out of the gate. Can go however long. Stop to fish for 10 minutes -- starts and will go for less than a minute and acts like its of of gas. Primer bulb has no fuel in it. 4-5 pumps --good to go till next stop. Same thing again..... Funny thing never does it on the first go of the trip.

I have replaced;
- Tank pick up tube
- Cleaned tank vent line
- All fuel line up to fuel filter on motor (replaced thin stuff inside cowl)
- New Water Fuel separator - base and filter
- LP filter
- New LP fuel pump
- New clamps on all lines
- New Bulb

Still does it???

Can air be getting into the vst - back flowing causing lose of prime ?

Bulb is usually empty - but fills with 1-2 squeezes

My next move is to take the intake off and tear into the VST.

Any suggestions ?

Stan

Pull the vapor hose off the top of the vst and make sure it, or the cam cover is not blocked. When you turn the motor off after a run, engine temp will increase so will the vapor pressure in the vst, if it cant vent it, will go higher than the low pressure pump and push fuel back down the fuel line, that is why your primer has no fuel in it. You should feel suction on your finger when you pull the hose off the cam cover with the engine running, also That will be why you have no problem when it is cold, no pressure in the vst.
The engine will run until it has used the fuel which is sitting in the bottom of the vst where the pressure cant push it back down the fuel line.

[artdf175]

might also check the fuel tank port for the fuel line
there is an anti siphon ball bearing type fitting that is known to not allow a free flow of fuel causing the primer bulb to go flat
other than that after what Redlowery mentioned make sure there isn’t an air leak
in the fuel line connections one way to check that is to watch the small inline filter pre low pressure pump and verify no air bubbles are present with the engine running
Art

[stushmd]

Thanks for the info -- will check that Vapor hose connection.

I replaced the fuel tank port pick up and changed the anti-syphon valve.

I really appreciate the suggestions !!


Stan