No crank hot

[1badstang]

Got a 1986 ezgo marathon with 2 stroke Robin 244cc engine. Got new generator on it cranks fine runs good for 45 minutes or so until it gets hot it
Will just die while you going not sputtering or anything. It has fire, it just turns over let it sit for 20 minutes it cranks right up and run 10 minutes and Same thing will just die like you turned it off but will turn over fine and I pulled wire off plug put it on another plug and it's got plenty of fire and it has new carburetor it's been doing this for a while any help will be greatly appreciated.

[newtjl]

I would imagine its starving for fuel if the spark is ok. When it shuts down, see if it will go in reverse. Crankcase pressure is what makes your fuel pump work and it creates suction on the intake, pulling gas from the carburetor into the cylinder. f the crank seals are badly worn, it will tend to lose that pressure as things heat up. If it starts and runs in reverse when it dies in forward, that tells the tale on the seals. With that being said, I was recently about to undertake changing the crank seals in an engine that was having your symptoms and tried a new fuel filter before doing the job. That fixed it for now. I suspect the old fuel filter was making the pump work a little harder than a clean one. I believe the seals are still short for this world but I bought some time for my customer and he knows that. He will bring it back this winter for the seal change. So if it were me, Id change the fuel filter first, pump second, and it that doesnt fix it, change the seals. If you have those three things, you will have fuel flow. One last easy thing to check though, make sure your fuek tank is venting. There is remote chance that a vaccum is being created and not allowing fuel flow. Just pop the gas cap off and try to start it the next time it dies to check venting off the list.

[newtjl]

As Columbo would say "Just one more thing" Make sure all the hoses that run to and from your fuel pump are in good shape and clamped. I have seen air leaks cause fuel pressure problems too. The hose from the crankcase to the fuel pump is a biggie.

[1badstang]

Ok thanks for your suggestions I have tried it in reverse and still just turns over and I have new fuel pump carburetor and fuel filter. The gas cap is vented but has same aluminum line on it to filter then it's all new 1/4 fuel line to pump and carburetor. I have 1 thing left I was wanting to ask. How about vapor locking. I know some young people may never heard of it but when my dad raced in the early 60s it was common so they would ice manifolds down. Could it be possible I need to wrap the fuel lines with muffler wrap and why they put that big can of a muffler right under seat beats me I know you take seat off and feels like 200° under seat. Thanks again for ya'll answer me and think about the vapor lock if ya'll think it's worth looking into. Thanks.

[newtjl]

If you have plenty of compression, it likely needs crank seals.

[cart around]

When I first read this, I also was thinking seals, and I still am.

There are some seal tests, most are unreliable. Spraying starter fluid on the seals is one of them. It works for the rear, but hit, or miss on the front.

You could try this. When it dies, pull the fuel line from the carb, and crank it over. See if it puts out a healthy stream of pulsing fuel. Again, hit or miss.

[1badstang]

Ok update on hot not crank deal I rode it 30 minutes it died no sputtering just like you turned key offSo I pulled fuel line from fuel pump to carburetor and no fuel. Again can let it sit 30 minutes it fires up pumping plenty of fuel. So I was saying it might be vapor locking and I guess it still could but would diaphragm maybe doing something stupid? And can you get a high flow fuel pump or heavy duty?

[newtjl]

You can try the fuel pump first, its cheap. But it looks like crank seals. Its not vapor locking. The engine is losing crankcase pressure as it heats up due to worn out crank seals. Crankcase pressure is what makes your fuel pump, pump the fuel. If the pump is tired anyway, you may buy some time with a new one. I recently put a new fuel pump and filter on a cart with worn out crank seals. It was doing the EXACT same thing yours is doing. Its working fine for now but the owner knows the seals are shot. He didnt have the money for the labor right now but is bringing it back this winter to get the seals installed.

[cart around]

It's not pumping fuel because the seals are leaking. The pump runs off of crankcase vacuum. When you lose the seal, you lose the vacuum.

[newtjl]

You can also jury rig it with a low pressure electric pump. I am not suggesting you do that, but some people do that.