372xp fuel problem

[Yotehunter66]

My saw started leaking fuel really bad so I found that the tank vent had come out. The saw ran that way for a few minutes and then died. I've replaced the tank vent, filter plug, impulse, supply line and tank filter. After all that it's still not getting any fuel. I'm going to take the carb apart tomorrow and clean and check any diaphragms. Is there anything else I should look for?

 

[w8ye]

Make sure you have the lines connected to the right places

 

[Yotehunter66]

Make sure you have the lines connected to the right places

Yeap. Changed them one at a time on different days.

 

[w8ye]

Plug the carb inlet to make sure you can suck some fuel up into the carb by turning the engine over to get the carb primed.

An old saw will have the air vent chamber of the metering valve stuffed with sawdust that may make the carb work in an unusual way?

 

[Yotehunter66]

Plug the carb inlet to make sure you can suck some fuel up into the carb by turning the engine over to get the carb primed.

An old saw will have the air vent chamber of the metering valve stuffed with sawdust that may make the carb work in an unusual way?

Is that normal after you change the fuel lines? I thought the choke would help do that. I'll give it a try.

 

[dansikes116]

I have built over 20 Husky 372 from the case up. Kit the carb to be safe and if you have a air compressor blow some air into the impulse line to make sure it is free of any obstructions but be conservative with the amount of air and the pressure you use. I always prime my tank by blowing a small amount of air in through the fuel line, make sure you have the line pinched off with one hand or it will squirt fuel every where. Next I will squirt a little gas in the carb and it should fire with no problems. Taking these steps always helps me get these running. Remember don't put to much air pressure in the fuel line you can blow the tank vent out if you use to much. Hope that helps!

 

[Yotehunter66]

I have built over 20 Husky 372 from the case up. Kit the carb to be safe and if you have a air compressor blow some air into the impulse line to make sure it is free of any obstructions but be conservative with the amount of air and the pressure you use. I always prime my tank by blowing a small amount of air in through the fuel line, make sure you have the line pinched off with one hand or it will squirt fuel every where. Next I will squirt a little gas in the carb and it should fire with no problems. Taking these steps always helps me get these running. Remember don't put to much air pressure in the fuel line you can blow the tank vent out if you use to much. Hope that helps!

Blow into the impulse line from the carb side to the crankcase or from the crankcase side into the carb? Is it possible to have a ruptured diaphragm so the impulse line could pressurize the tank and that's why I lost my tank vent?

 

[w8ye]

It is easier to blow through the impulse line from the carb through the engine.

The vent in your case was a different problem

 

[dansikes116]

Blow into the impulse line from the carb side to the crankcase or from the crankcase side into the carb? Is it possible to have a ruptured diaphragm so the impulse line could pressurize the tank and that's why I lost my tank vent?

Unplug the impulse line from the carb and blow into into the side of the line that plugs into the carb blowing into the crankcase loosening any carbon build up. Do the same to the fuel line.

 

[w8ye]

If you are going to blow into the fuel line from the carb - be certain to remove the gas cap or you will blow the vent out again.

 

[Yotehunter66]

Thought I would give an update. Pulled the carb and cleaned it and still no fuel to the cylinder. Carb was full of fuel but the plug is dry. Blew through the impulse line and that was clear. Ordered a new carb for it today. Hoping that will solve the issue.

 

[Zippy]

Some options to try.

If the metering side (with the lever and button diaphragm) was full of fuel there's only the circuits past the H and L screws left to go until the fuel gets into the venturi and the engine.

You could try removing the L screw and squirting some carb cleaner or even WD40 (using the straws supplied pressed right onto the seat) and checking it comes out the holes in the venturi. If it does then there are no blockages.

You could use the same straw in the H hole (L closed off) and gently blow and suck and see if you can here the H jet valve moving. If it's not you can draw air in through the H circuit and out through the L circuit when trying to start - so you don't end up with any fuel being drawn down.

Could check the butterfly valve plate is ok - ie holes line up with L circuit orifices in venturi

Carb kit as suggested before is a good idea - possible the crank pressure is getting past a ruptured diaphragm and pressurising the tank - would need to think a bit more about that to be sure.

 

[Yotehunter66]

Okay, latest update. Put a new carb on it and still no vroom! Piston looks like it is wet on top but the plug is dry. Going to check the compression this morning. Hopefully I'm not looking at a rebuild?:bang: