80 shifter won’t stay running

Hey guys,

New here, I used to race clones 10 years ago, moved to cars and bought an 80 shofter last year to mess around with. I’m not too experienced with 2 strokes but my dad always used to take care of our 2 stroke dirtbikes as kids.

We’re having trouble getting the kart running. Fuel pump lines were run wrong at first, fixed that, then the kart would bog at low rpm and a light blip of the throttle would rev it SUPER high, but I could get it up to speed and run fine.

Now, the kart is very hard to start and simply will not atay running. We’ve replaced the reeds and we’re stumped on where to go next

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As you probably guessed, there’s a lot fo things it could be. How did it behave when you tried to adjust the idle?
Air leak is worth checking for, disassemble and clean the carb. Check the boot for cracks. Re-check the gasket for the reed cage.

How is the compression? It sounds like the carb may have the wrong jets in it. Could be a crank seal issue. Just as James said, it could be a couple of things. It is a process of elimination with two strokes. It is not too difficult. Good luck. :slightly_smiling_face:

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The fact that the idle and engine rpm is all over the place sounds like a fuel supply issue. This could be due to a bad pump (perhaps a rebuild or clean is in order), air leak in old fuel lines around fittings or a small air leak you’re not seeing, or of course poor carburetor settings, although you’d likely have to be way way way off for it to not even run somewhat on the stand.

One thing a lot of racers overlook when diagnosing things like this is the pickup plenum in the tank. The gasoline tends to eat away at the line that goes to this fitting, and every now and then a leak can form at the fitting or the plenum falls off, which causes all the issues you’re describing.

Good callout, especially for a kart that has been laying up.

Finally took a crack at it and changed to a new fuel pump. It runs, but doesn’t want to stay running when hot without the choke. Going to poke around the carb next. Sounds like it isn’t getting enough fuel.

Have you serviced the carb yet? Disassemble, clean. Check float heights and inlet needle (assuming it’s not a pumparound setup)