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Rebuild or just clean carb?

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Good evening all! 

First, thanks to all of your help last week which got my AC 312H started and running great! Put in a new battery after replacing a bunch of wiring, and now it starts the first time, every time. I've still not run it all too much, as I am planning to change out all the fluids later this week. 

The only issue I have had so far, is one time after running for maybe 10-15 minutes while test driving around the yard, the engine stalled and started to overflow fuel out of the air filter. I suspected that it might be a stuck float valve, so I gave it a couple of gentle taps, and it is now starting and running just fine again. 

What would you all suggest I do next with regards to servicing the carb/fuel system?




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Is there an in line fuel filter between the fuel tank and carb? If not, install one....if there is one...replace it.

 A rebuild kit is very inexpensive and an easy install. You need to be cautious that fuel did not run back into the engine oil and crankcase and thin out your oil when carb overflowed.

I myself would buy a kit, drop the bowl and clean any debris or dirt out of it. I would pull the float pin, drop the float and needle valve, spray carb cleaner into needle valve seat to be sure varnish is not hindering the needle movement, install new needle on to float, replace carb bowl gasket and reinstall the bowl,  All can be done with carb in place. If carb was running good ...you should be set to go. You can also change out the air mixture screw if you want if you just keep track of how many turns it takes to remove the old one but if engine was running excellent,  I myself would not bother. 

Good luck.

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Fishnwiz is right on target. My 314 had this same problem after restoring. I had a new filter but very fine rust dust kept getting in carburetor bowl and also under needle seat. It finally purged itself clean. I bought a new carburetor for $20 off ebay and it performed well for awhile then it started overflowing that is when I discovered the rust problem. After cleaning out the float bowl a 2nd time it has ran fine.

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