RK-Aircraft

My Feedback: (81)

So... I've inherited an OS MAX-H 40 which I know nothing about other than it looks OK and appears to use a muffler that thru-bolts up to a threaded sleeve that is in the exhaust port. OK, here's my dilema. Should I spend any effort on getting this thing to start? The carb seems to be plastic with brass hardware and a plastic throttle valve needle. Does anyone know this engine? [sm=confused.gif]

Bax

My Feedback: (11)

If you have a carburetor that's mostly plastic, then it's not the original O.S. carb. The muffler used on that engine was a strap-on. The screw hole in the center of the exhaust port is for the exhaust baffle that was used before mufflers were commony used. The baffle closed-down the exhaust port as the throttle was reduced to help keep the glowplug hot.

We do know that the smaller engines had mufflers that bolted to the one screw hole in the port, but the .40's we saw all had strap-on mufflers.

If the engine turns over smoothly and has good compression, we don't see why you couldn't run it.

RK-Aircraft

My Feedback: (81)

Thanks, Bax. Well that sounds good. It does have good smooth compression. Do you know what carb will fit it? or where I can find a muffler?

Bax

My Feedback: (11)

Measure the diameter of the carb boss. We think it's 13mm. You'll need to double-check. Any carb intended for .40-.50 size engines that will fit into the carb boss will be OK.

The current O.S. carb for that size is 13.5mm. You may be able to make it work.

OSMG2448 25381006 CARBURETOR #4D 40-46

RK-Aircraft

My Feedback: (81)

I'll go measure. Meanwhile, can I get a strap-on muffler from tower that will fit??