A friend of mine gave me a Ryobi weedwacker engine that he had converted several years ago for model airplane use, but never did. It has a Walbro carburetor (WT312) that has two brass tubes coming out of it. The smaller diameter tube near the high and low end screws is the fuel pickup. Can anyone tell what the slightly larger diameter tube on the opposite side is used for? Is it used for pressurizing the fuel tank? I've been to the Ryobi and the Walbro sites but can't find this particular carburetor. I'd like to get this engine running on a test stand before I stick it into an airplane. Joe L.
Ryobi engine
Oct 06, 2003
3 Replies
That is a primer fuel entrance. The engine won't run correctly if it is left open. You should either solder it closed or put a short piece of fuel tubing on it and tie a knot in it. I have a Ryobi that I fly regularly and I have the primer hooked up. Don't need it. Eddie Fulmer AMA 63713
Gasoline engines do NOT pressurize the tank.
However, there were several Walbro carbs that had little prime pumps and I suspect that may be the remnants of it.
Thanks Eddie and Six_O'Clock_High, I think you guys are right and that this tube is for priming the engine. I will close it off and see what happens. Joe L.
Join the Discussion
Have something to add? Share your thoughts — no account required.
Didn't find your answer?
Ask the community — no account required