1990 3pg engine cuts out when hot

[Nascarfastcar]

I have a 90 3pg 2 stroke that I rebuilt about 2 years ago.
Just bearings and crank seals. Top end was good. Still showing 120psi.
The cart runs and starts perfectly but if you take it on a long drive the engine starts to big and loose power but will pick itself right back up if you keep on the throttle. I don't have to use the choke or anything.
Let it cool down it runs fine.
I'm suspecting a fuel issue like the pump or gas cap. The pump is original off another 90 I have. And the cap on the tank isnt the original one with the fuel gauge. Should I drill a small hole in it?
Also on this cart I never got around to doing a hei swap but instead I threw a old tractor coil in it. I'm also suspecting when the coil get shot it might be causing a issue.
Could I run a hei coil without swapping the ignitor and all that stuff? It's not like I can't do it but I just don't have the time for it.
Muffler was also bbqed 2 years ago. It probably wouldn't hurt to do it again but the cart has had limited run time since. Also running 128:1 premix

[Dabble Inn]

The gas cap must be vented, maybe it's starving for fuel after running for a little while..

I really don't like the idea of a tractor coil either, maybe it's getting hot. These S/G can put out up to 15volts, I'd suggest putting a stock coil back on it... 128:1 premix is a great idea, but don't use premium high octane gas. Good ole 85-87 octane is what it wants.. Good Luck and let us know

[Nascarfastcar]

Originally Posted by Dabble Inn

The gas cap must be vented, maybe it's starving for fuel after running for a little while..

I really don't like the idea of a tractor coil either, maybe it's getting hot. These S/G can put out up to 15volts, I'd suggest putting a stock coil back on it... 128:1 premix is a great idea, but don't use premium high octane gas. Good ole 85-87 octane is what it wants.. Good Luck and let us know

I'm gonna drill a small hole in the cap. Never had luck with stock coils or aftermarkets. My other carts have hei coils but I was wondering if I can run a hei coil without swapping out the ignitor.

[Dabble Inn]

Someone else will have to chime in to help you with the hei thing, I haven't had to do one yet so don't know. But yeah vent the cap and run it.