What would cause my engine to surge and cut out once it leaves the ground and is ascending? It runs great on the ground and once airborne, including aerobatics, it runs fine. Appreciate any suggestions.

your mixture is not right or sumthin, my MDS 40 was lke that on take off one day, i took off and got a deadstick, she was only like 4 ft off the ground. I brought it back, a guy came over, helped me out. We ended up changing the glow plug and reset the mixture because the heat change compared to last year.


also if i dont let my mds warm up enough, it will sputter and evertually die when i give it full throttle

Sounds too lean to me on the low end or as was already stated not warm enough before takeoff. Once airborne you are probably flying at or above half throttle which is more the high speed needle then the low end, but during takeoff and climb you are transitiong from low end to high end and the low speed needle will cause this

Thanks guys ... that's kinda of where of I thought the problem could be. I'll rich it up a bit on low end and go from there.

That's exactly what is the problem, it's too lean. A trick that will help you is when you are tuning the motor on the ground lift the plane up and hold it with the engine pointing straight up for 30-35 seconds with the motor running full open. Make sure you lift with both hands and that you have a firm grip on the plane. If your motor is tuned properly the motor will continue to run at full speed. If it sags off or dies then you have it too lean and need to richen it up.

Hope this helps

Ken

plane freak you said a bad word mds and dead stick in the same sentence..............i was just curious are the smaller engines as funny on the carburetor settings as the bigger ones are i have a 78?i haven't really had any problems with mine except had to nylon tie the muffler to the body,i lost one.but the remote needle seems to stay wet i cant actually see a leak Ive pressurized it and all,replaced the copper washers.i have about 2 hours on the engine now and the carburetor settings seems to be getting better.....happy flying

Problem solved! Too lean of a mixture, adjusted accordingly and it runs great. Thanks for the advice!

Your engine is not properly tuned up-both low and high end.

ya ive had some problems with this thing, ex, take off slpurging, had to pull the needle valve out SEVERAL times and regrease it, my bearings are just about shot ( i should change those), but this year i havent had any problems with it really this year except mixture. AND YES I SAID DEADSTICK AND MDS IN THE SENTENCE, luckily i had a strong tail wind to push e pack a bit, otherwise i would have been in weeds