ALO 111

Will a 2 stroke motor run as well mounted inverted as a 4 stroke?

aussiesteve

I'm getting the beer and popcorn (or maybe the Mou Tai and chicken feet) out to watch this one.

My answer is short is - Yes - in most cases. As long as it is properly tuned, with the correct tank height, in good condition (such as no crankcase or carby leaks etc) and the correct glow plug.

Personally, I prefer to not mount the engines completely inverted if i can avoid it - I go for 90 degree mounting or somehwere between 135 degrees and inverted. Of course you can't always do that.

fiery

My Feedback: (2)

I'll wade in

Generally, no, not without band-aids (i.e. extended tip plugs, a la O.S. "F", Fox Miracle etc; or on board glow heat at low RPM's).

That said, reliability can be achieved, but watch your tank placement to avoid too much fuel head, or you may need to to look a regulator set up as well.

XJet

I've never had a problem with an inverted 2-stroke engine. Just watch the tank-height, use a decent quality motor and make sure the needles are tuned properly.

asmund

In a word, YES.

I have never had a problem when the needles are tuned correct

ALO 111

Why I ask <I just got my hands on an old 60 size cub with a 0s 60 mounted inverted in it.
Its needs some repair due to a dead stick on takeoff. The previous owner said it used to run well but he later had trouble hense the dead stick. I will open it up and give everything a check first otherwise will fit a 4 stroke.

Jezmo

I've got a Scooter II that I have been flying for almost 20 yrs. It has an OS 40 FSR on it inverted and only dies in the air for two reasons. 1. Out of fuel 2. Glow plug failure. The first I can control, the second is a bit more difficult to predict, but still extremely rare. I don't feel that I have had any more dead sticks out of the Scooter than any other plane I have had that the engine was mounted right side up. It's my belief that it all boils down to the right setup which has been mentioned above by Steve and X.

Turk1

Only problem is almost impossible to prime an inverted engine.If you have an electric starter there will be no problem at all.I have used 3 inverted engined models (in cowling)and never had any overheat problem or fuel feed problem.I dont have any electric starter and my only problem is to prime them properly to start.Another risk is fuel drainage by siphoning by carb to ground while resting on full tank if you dont be careful.

YUKONFLYR

I have an inverted Supertiger 75 in a Mustang and it does not know that it is upside down, runs great.

I do pull the plug prior to spin the engine over to get out the extra afterrun prior to attempting to start the engine.

Richard