cant shut my GMS 47 off without pinching the fuel line. It runs well. I wrote the manufacturer an email and as usual no reponse after a month. The engines are great!!!! Where can I get an O ring that fits? I believe its a 1/16 diameter. I cant seem to find any. Havent measured the od of the carb. Is there a Tower replacement OS type carb that will fit in the crank case that you know of? What part number is it? I love the GMS 47 for power and have two of them. I know the leak is in the carb setup as I interchanged the carb and it shuts down properly with the new engines carb. I would hate to try a warranty claim with the disclaimer that accompanyed mine in the box. NOTE: You may have to install a fuel shutoff valve in the fuel line to shut down the engine. Now what kind of mickey mouse is this?

Too bad you didn't do a search on this website concerning this engine. You would have found out that this is a design flaw in the engine and extremely common. Some claim that its not the carb but a front bearing that allows for airleaks. This problem has been fixed by some folks who replaced the front bearing with a sealed bearing from boca bearings.


Take care,
Andy

Thanks Andy, I will do a thorough search, however, I still need the correct size O ring and have a valid question as to how to obtain the correct one. This may not fix the problem but right now the O ring I have installed after having disposed of the one that came with the engine is the wrong size and precludes the carb from nesting in the crankcase correctly. I stil need one. This may not fix it however and I can put in a new bearing then as you suggest to fix it. Funny it worked for awhile. The carb has two O rings. One down in the bore and one at the top. If the top o ring is not in the groove the carb appears to not reach the one in the bottom of the hole and could leak. Design flaw, yes!!!!!! Note: I have two of these new ones. I interchanged the carb setup and O ring from the one that has never been run to the one in my plane and it works great.
Thanks for your tip.

I dont know the size of the o-ring, but take the carb and engine to your local hardware store and find one that works the best. I have done this with other engines and have had good luck.

I have a couple of these, replacing the front bearing did the trick. The factory ones breathe just a bit too much.

The Macs muffler does wonders for it. Big boost in fuel pressure and reliability with little or no loss in peak RPM.