What would make gas flow out of the spark plug hole on a briggs and stratton 18hp ohv intek?

SOURCE: Briggs & Stratton Briggs Stratton Intek V -

these are common for doing this ,if you dont want to pull it down and hone the cyl. then i would use a heavier oil say 20w/50and that will probabley solve your problem

SOURCE: 18hp B&S wont slow down no matter where

It's one of two things. Most likely, the screw(s) have come out of the butterfly valve on the throttle shaft and letting it run wide open. The second thing is that the governor gear inside the engine broke. Unless you a pretty good mechanic, I'd recommend taking it to a shop. If it is just the butterfly in the carb, you still have to deal with...where did the screws go? They may have passed through the intake and exhaust valves or they may be stuck in one of the valve seats or embedded in the piston. Like I said, better take it to a trusted shop, if there is such a thing, unless you live close to me. lol.

SOURCE: briggs and stratton miss fires on one cylinder.22hp intek

possibly a commpression test might throw a little more light on the situation ,that will eliminate alot of speculation, and make it easier

SOURCE: B&S Intek OHV 18hp muffler glows red hot

sounds like its running too rich on fuel. try turning the fuel mixture screw in 1/4 turn at a time til it starts to stall then turn out 1/4 turn or 2 and see if that helps.Maybe when you used the air it turned this screw???

SOURCE: what is the gap setting for RJ19LM spark plugs for

mine calls for .035

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