My Thunder Tiger Pro 46 sounds like popping popcorn, is this the norm? I think I may have read somewhere that its running hot but I cant remember. If thats the case I do have some Klotz raceing oil<< I think thats how its spelled, but it dont say how much to add to the fuel. Any pointers.

I think it is just running too lean and therefore getting hot. Richen it about 4 clicks and see if that doesn't help.

Also, check the back plate screws and see if they are still tight. One of my Pro 46's came new with the screws finger tight and three vibrated out and made for lean running and lower crank slop.

if you can't see white vapor cmming out of the exhaust... its too lean.

More oil won't cure it... it may make the engine slow down some and it may cool it a little because of that... but too lean is too lean and will damage the engine.

It's either detonating from being too lean or you are 4-stroking it. It will run a little rough when it is real rich. Is it making alot of smoke?

If it is like an air popper then it is rich

mmmm.... buttered popcorn.

*goes to kitchen*

When its flying and hit throtle up I can see smoke. Kind of like a car with a old holly carb on it. I think maybe to rich then. I tunned it right I thought. I got top RPM out of it then riched it up a bit. Maybe I went a bit to rich. I fly today so I will try to lean a bit or rich which ever does the trick.

Have somebody hold the airplane straight up while you adjust the needle. Move the throttle to full open, lean the engine fully and then back it out about 1/4-1/2 turn. You should hear the RPM drop slightly. That should get you very close to the right setting.

- Paul

You can also use the pinch test to check and adjust.