help. engine problem
 

hello guys,

i am the happy [&:] owner of a magnum 46 xls engine turning a 11x8 graupner grp propeller. the engine is new, bought it last summer. all summer ran fantastic, had no problems with it.

EPISODE I:

last weekend it started to snow and we went flying. it was arround 0 degrees celsius. the engine started with no problems but barely managed to get a stable half-throttle to fly it.

EPISODE II:

today started to tweek the engine. changed to a top flite power point 10x6 prop, changed the glow plug (use a robbe no 3 hot glow plug), readjusted the high and low speed needle valve)

no luck. when i accelerate the engine gains rpm like it should and right after that it looses power like it's starving for fuel. I back up and try again, the same thing happens. the idle is wonderful, but from half throttle up it doesnt run. if i don't back up the engine eventualy dies. same thing happens even if i keep the glow plug powered.

does anyone have any idea what is the problem? by the way i am using jamara magnum :D fuel with 5% nitro and 18% oil

please somebody answer quick cause tomorow i want to go fly.

red_guy

RE: help. engine problem
 

A couple of things you might try. Wrap the cylinder with a couple if turns aluminum foil, held on with a rubber band or tape to keep the cyl. running hotter. Higher nitro, 15 to 25% would help although I don't know if Its available where you are. I use 25% in the winter time. Set the high speed needle valve while it's running.

RE: help. engine problem
 

WOW!! that sounds just like my engine! I have an MDS .28 engine that has been fairly reliable for the last few years but sometimes it acts just like your saying. The engine idles fine and low speed RPM's are fine, but full throttle only lasts for so long before it slows down or dies if you dont do anything. THe solution to my problem so far has been richening the mixture. If your engine is lean it may run rine at low throttle but begin to starve itself as the RPM's increase. Also replacing the glow plug can help very much. Since you already replaced your glow plug try richening out your mixture and dont be arfraid to really crank it richer, it will probably help. Also it might be good to use higher nitro. I never use less than 15%.

RE: help. engine problem
 

Oh yeah and one more thing. Check how well all the pressure lines are from your muffler, and make sure the baffle is still in place inside the muffler. make sure there are no holes or cracks in your pressure line, and replace them if there are. If none of that helps check inside your fuel tank to make sure the pressure line hasnt gotten plugged up or kinked or anything like that. Hope all this helps.. good luck!

RE: help. engine problem
 

I want to thank you all for helping me. Today I got the engine running. The high speed needle assembly had A LOT OF DIRT (FIBERS) STUCK IN IT. After removing these fibers the engine ran perfectly. Thank you again for the help.

red_guy