Hi,

Been playing with my converted Honda GX 31 four stroke. Using a spring over the pump diaphragm in the carb and an external pulse line from the manifold to the carb pump cover, I got a WT type two stroke carb to work. I made an adapter that necks down from the outlet throat of that carb to the inlet diameter of the engine, added a velocity stack, and it works very well. I converted the engine to electronic ignition, and made a straight stack exhaust outlet. With these mods and all dialed in, it turns an 18 x 8 wood prop at just shy of 7000 rpms. This isn't bad considering, but as always, I WANT MORE!

I haven't bothered to look it up, but the stock compression ratio must be horribly low. It is so low that it is almost difficult to tell which is the compression stroke when turning the prop over. It also won't even think about hand starting, though it takes off the second you touch an electric starter to it. It is so low, that I just now pulled off the valve cover and checked the valve clearances, thinking they might have tightened up and the valves weren't sealing well, but no such luck.

So that got me to thinking about the options for a low compression 4 stroke:

1. Raise the compression!! (Not likely with this engine design.)
2. Supercharge. (This engine is a great candidate for forced induction, but I'm not going to make a blower!)
3. Turbocharge. (See above!)
4. Nitro. Hmmm, now that is something I am thinking about.....

Anyone else playing with their Honda GX 31??

AV8TOR