New pump not pumping to carb - why?

[fixitdad45]

I'm working on a friend's Huskvarna mower which has a 24hp B&S v-twin. When I got it the engine would just crank and crank, no signs of starting. I found there was no fuel coming from the fuel pump outlet (hose to carb detached - nothing coming from pump when key turned) so I replaced the fuel pump. Same problem. Fuel dribbles at a steady rate from the fuel line from the tank which means the pump would get fuel so I'm thinking it's the pulse line.

I did a quick check of the 3" of pulse line that's visible to me outside of the valve cover and found no obvious issues. The mower is a 2013 model so not much time for dry rot. Rubber still feels nice and soft.

Part of me wants to pull the valve cover but I don't have a gasket to replace the current one with and I'm not sure if there's anything worth seeing in there after breaking the gasket. Can someone tell me what may be going wrong here please? Is there something lurking behind that valve cover that I really need to look at?

Thanks,

Scott

 

[BlazNT]

What you are looking for is something in the fuel line. Take it all off and blow it out. You do not need 90 psi so turn it down. I hardly ever tear up a valve cover gasket. take it off and gently remove cover.

 

[fixitdad45]

What you are looking for is something in the fuel line. Take it all off and blow it out. You do not need 90 psi so turn it down. I hardly ever tear up a valve cover gasket. take it off and gently remove cover.

I get steady flow via gravity from the tank, through the filter and out of the line that goes into the fuel pump. Are you saying I need to check the pulse line for an obstruction?

 

[Boobala]

Take the line off the carb then crank it over... see if you have flow into the carb ...BE careful with fuel lines.....FIRE !!! fuel pump only works when engine is turning over.......not just with key on ...

 

[BlazNT]

After you test Boobala said the yes check the pulse line. I personally would check all and the gas tank. May have something covering the drain hole that only covers when pump pulls it down to cover outlet.

 

[fixitdad45]

After you test Boobala said the yes check the pulse line. I personally would check all and the gas tank. May have something covering the drain hole that only covers when pump pulls it down to cover outlet.

I've already confirmed that fuel doesn't flow from the pump when the engine is turned over. I'll next take things apart enough to get to where the fuel line comes out of the tank - hopefully there's a piece of junk in there that's acting like a flapper over the fuel exit under pressure.

Will let you guys know what I find.

 

[fixitdad45]

I put some compressed air through the fuel line where it exits the tank and to just before the fuel filter. All clear.

The dip tube fuel sucker straw inside the tank is also clear. The line from the filter to the pump is good as well.

I tried taking off​ the valve cover but it's very well glued to the cylinder head and I'm going to bend metal if I try to take it off with a screwdriver. Suggestions for removing a stuck valve cover?

Also, can someone tell me how the pulse line terminates inside the valve cover? Does it just end, hanging loose in there, or is there something attached to that end that could possibly be causing this issue?

Thanks

 

[BlazNT]

Watch this video.
https://youtu.be/jdS36RQkFc4

 

[fixitdad45]

I used the video suggestion to pull the pulse line and confirm it's good to go. There's no wear, cracks or blemishes.

What else is there to cause this fuel pump to not work? Could it be that there's no or not enough compression under the valve cover?

 

[bertsmobile1]

Very first thing to check is the tubes at the pump.
Most people plumb them together wrong despite the fact that there are generally arrows cast into the pump.
The one on the circle is the impulse line it blows & sucks on the diaphragm the ones on the side are the fuel lines.
Usually the in line is the one nearest the the impulse line and the out line is the one furthest away
Look closely and you should see an arrow on the body or tube somewhere.

Blow & suck on the impulse line, it should only move a little bit both ways if the diaphragm is in a good condition.
With the other two, there is a one way valve inside the pum so you should be able to blow but not suck on the in tube and suck but not blow on the out tube.