Carb losing prime

[pabird 40]

Happy holidays everyone, I've got a neighbor who owns a 310-8 with a fuel issue. It seems that the fuel will syphon out of the carb if it sits a while making it hard to start. He has a plow on it and only uses it to push snow. Do you think this is a carb float problem or a fuel pump problem or something else? He said he has fuel to the pump and the pump will pump to the carb. Any help appreciated.

[clueless 2,902]

Hard to start? With the choke out and the throttle up how long does it take before it fires? These with the kohler flatheads and the fuel tank in the back can take some time to start if they have been sitting. The more hours on them the longer it takes. My 312-8 can sit for two or three months, it can take 10 to 20 seconds to fire up.

 

[AMC RULES 36,954]

 I imagine the quickest, easiest fix...

would simply be adding a fuel primer bulb into the tractors existing fuel line. 

[clueless 2,902]

10 minutes ago, AMC RULES said:

 I imagine the quickest, easiest fix...

would simply be adding a fuel primer bulb into the tractors existing fuel line. 

Craig nailed it. Put one on my 312 under the seat pan, lift the seat, give it a couple of squeezes she fires right up even after sitting for four months. Don't even have to squeeze it if it's been sitting for two or three weeks. Cheap fix .

[pabird 40]

Thanks guys, I’ll have to get more details but if you think it’s a normal situation I’ll let him know about the primer bulb. 

[953 nut 51,939]

The has three components, a check valve on the suction side, a check valve on the outlet and a diaphragm that creates a difference in pressure between the inlet and outlet. After time the check valves begin to leak by slightly and though it will pump well enough the fuel will leak back to the tank. I have a couple of tractors that I have added small check valves on near the carburetor to solve the problem.

You can find them on           

1/4" Plastic One Way Inline Check Valve For Fuel Diesel Gas Liquid 

 

    

[pabird 40]

Thanks for the replies guys. The pumps are cheap, will recommend he change his.

[Ed Kennell 35,919]

There is no guarantee a new diaphragm fuel pump will hold it's prime.  Most do not.

The primer bulb, shut off valve, the check valve, or electric fuel pump will fix the problem.

If he wants a cheap fix, just fill the tank after every use.  This will keep the fuel level above the fuel pump and keep it primed for the next start up.

[pabird 40]

Thanks Ed, I've explained all of this to him and he can decide which route to take.

[Larry Chamberlain 16]

So I have the same issue with k301 what electric fuel pump do you suggest I seen ones on Amazon for like 12 bucks they are 12v just didnt know what the flow rate would need to be

[peter lena 8,098]

@pabird  evil energy 5 /16 aluminum fuel check valves ,https://www.amazon.com/Automotive-leader-Return-Petrol-Aluminium-  will hold the fuel there , that diaphragm  fuel holding point is the issue , also use a clear fuel line in that area , from pump to check valve to carb , note last photo , clear fuel line from pump to check valve , note arrow flow FACING UP TO CARB , dark green squeeze clamps , measure and put this together , before you install it , makes it very easy . tiny bit of dielectric grease , in check valve hoe ends , make for easy slide on . this works , have it on 3 engines . pete