mounting upside down
 

hi! i know most of the fliers do this a lot. i have an airboat with a gas engine. i mounted my engine upside down. does the carb be mounted downward also or you have to rotate it so that the bulb is still up?
i notice difference in the way my engine runs, but i'll save that question later.
thanks a lot!

ernest

RE: mounting upside down
 

The Ryobi 31cc I did came out of a string trimmer and was inverted in the trimmer so thats the way I'm mounting it in my airboat . It runs great and it will lower the weight closer to the top of the hull . I don't think it makes any difference where the bulb is . The carb on the Ryobi is in the back and I just removed the primer bulb and plugged the line at the carb .

RE: mounting upside down
 

It shouldn't matter which way you mount it.

Therer are several US 41's at the flying field and some are upright and some not. They run the same.

My Ryobi is upside down but my Homelites and Macs are rightside up.

Enjoy,

Jim

RE: mounting upside down
 

thanks for the replies. well my engine is a stock homelite 25cc. i did notice difference when i mount it inverted. first, the engine revs up to the max throttle, whereas when it was mounted upright, it struggles at full throttle. but the problem was i cant make sudden change in throttle or the engine dies. i then rotate the carb so that the bulb is on top again. this solves the engine dying in sudden throttle changes. but the old problem somewhat reoccurs, although not much.

RE: mounting upside down
 

well a 2 stroke with a diaphram carb. can be mounted upside down, right side up. or spun around in any direction while running if you would want. the carb works off of crank pulses which means that you do not need the fuel tank to be pressurized (glow engines)or gravity fed (4-stroke lawn mowers with a bowl carb). so for this reason a weed wacker engine is good for our radio hobby. just use a resistor plug to reduce engine noise.