Poor engine performance

The consensus on the K & Bs seem to be that they need much break in time.

My suggestion would be to run it for a couple of hours more on the test stand (rich, of course) and then evaluate it again.

I was actually considering doing that anyway, because I was at a complete loss. I did notice when I first bought this engine it would actually kind of grab at TDC, so perhaps it is a bit extra tight.

Thanks...

If anybody has any other bits of wisdom please post 'em.

I'm a compllete noob at this stuff.. but is there a point at which adding more rpm's to a prop becomes ineffective? Perhaps a different pop is needed? Again, this is only a question, not a suggestion..

Yeah, I considered that. I've tried a few different prop sizes and none of them are getting the kind of RPM that they should.

What plug are you using, and what others have you tried? Try a fox miracle plug.

This tightness at top dead centre is not bad at all, and the running engine does not notice it since the liner will expand, and oil wedge pressure also expands the liner. Just run in some more, use sufficient oil, and give the engine a break. It should improve in time.\ If it does not, sell it on E-bay :-)

This may be dumb, but is the cylinder the right way around? The transfer ports must open later than the exhaust port. It never hurts to check.

It sounds like you may have it over propped.

Considerably

Well, I don't remember if I ever took the thing apart. I don't think I have. I could check though.

I've tried everything from 9-4, 9-5 and 9-6. 9-6 used to work fine on my sportster .20, although that's probably somewhat overpropped.

Wow! way too much prop, IMHO. I use a 9 x 6 on a .40, to get it wound up on a small plane! Try a 8 x 4, or 8 x 5.

These do accept larger props than most comparable motors. I ran an 8*6 MA on my 20, and a 9*6 MA on the 28. It didn't have any problem with it. I'd asked earlier about the glow plug. What have you done in that area?

Lastly, the carbs are the same on the 20 and 28 if you want to swap and see if it makes a difference. If you have the remote needle on the 28 it doesn't matter, they can still be changed. The early 28's, like mine, had the needle up front.

Hey, I'm just going by the manual.

I haven't had much of a chance to work on it lately. I haven't messed with the plug but I intend to. Also, pulling the carb off my older .20 sounds like a good thing to try. I'll have to do that.

Hint: If the 20 is running good, swap the plug. Always start with the plug.