QuestionThis motor has not ran for a long while. I Got a new gas tank and replaced the
fuel filter. The tank was rusty. The motor will run great for about 2 minutes and
then it will cut off. There is gas coming out of the bolt on the bottom. Do you
think the there is something wrong with the carb or something else
AnswerIf the engine runs decent for that two minutes then I think I'd start my diagnosis by loosening the cap and trying it like that. If there's no difference, then do the basics, pull the fuel line from the carb and see that fuel flows well. If so, then I'd pull the carb. Having set up for awhile it should be gone through anyway.
I wouldn't bother too much with trying to find a specific problem in the carb. I'd disassemble the thing and drop it in a cleaning vat for an hour or three. Then use some fine wire and chase all the holes and blow dry with air. Then reassemble with a new carb kit and see what happens. If you haven't already, replace the fuel line too.
If this doesn't make any difference or if the engine barely runs for that two minutes, then I'd take a compression test first and see what sort of number you get. You can't rely on the compression number to be accurate due to the compression release, but if you've got 20 psi, then there's a problem.
Personally, while the carb is soaking, I would pull the head and give it and the top of the piston a good cleaning, I'd watch the valve motion and see that they're opening and closing and seating. I'd replace the head gasket also. Then I'd pull the exhaust and see that something hasn't made a nest inside. When installing the exhaust, use high-temp anti-seize on the threads. I use it on the head bolts too, but some people won't.
For soaking a carb, you can use one of the soak cans that you find at any auto parts store. But, by the time you buy that and a carb kit, you may have been able to buy a carburetor. We replace about 1/4 of the 4-stroke carbs that come through the shop, so you'll have to decide what's most cost-effective for you.
