pauluk2w

My Feedback: (7)

the os .46 max fitted in my nexstar will not idle at slow speed. i got to the field again today but after 2 hours myself and a guy from my club could not get it to start. for the last few flights i had last week on this plane every landing was deadstick one landing damaging the plane. i tried to tune it when i got home but it still would not start. the only way it would start was to use an electric starter and after about 2 seconds remove my finger., but after it runs for about 3 seconds cuts out again any suggestions on what could be wrong?

The Ghost

Could be several things. Bad glow plug, Fuel blockage anywere from pickup in tank right through to spray bar in carb, Loose back plate on engine,(have seen serveral) or the engine could just be worn out. You don't say how old the engine is or what fuel you use or how bad the impacts with terra ferma have been.

Cheers,

pauluk2w

My Feedback: (7)

I replaced the glow plug today with one that has an idle bar. fuel is getting to the carb ok, and all impacts have been very minor, the engine is only 5 month old. its just got me beat right now

The Ghost

The 3 things needed for an engine to run are Fuel, Air and spark(Heat glow plug) provided that the mechinical part of the engine is OK. So there is a problem with one or more. Check that there is no blockage in the spray bar of carb that moves and blocks it when fuel gets there. All crankcase screws tight and no leaks!

Cheers.

AlaskaRCer

A few buddies and I have these, they are great trainers, seeing how I am new at this. We have had some crashes and have re-built them. I had a problem like that and found that I had a pinched fuel line. Another buddy discovered a problem in his fuel tank, one of the hard lines was bent up. Just a few things to check. Problem with mine was I took off anyway and couldn't full power, kinda landed on a store roof, rolled off the flat roof and hit the ground, thank god I had my flaps down.....Good luck.

bubbagates

My Feedback: (32)

Sounds definitely lean.

Screw in the mixture screw until it stops (it's inside the hole where the throttle arm is and back it out 3/4 turn, this is factory settings. Then screw in the highspeed needle valve and back it out 1 1/2 to 2 turns, again factory settings. The try to start it. On an OS the mixture screw is for starting and up to approx half throttle. The mixture screw or the seat for it could also be damaged. These setting are right out of the OS 46AX book and should work for the FX, I'm not sure about the LA though.

http://www.osengines.com/engines/airplane.html

Their site has the engine manuals on it.

I would also take the carb off and make sure the gasket (o-ring) is there and in good shape as well as going with the other suggestions

SENZA

Pauluk, Go by bubbas settings i agree with him, i have set up a few nexstars right out of there boxes, they would fall flat on there face when you slap the stick, it sounds like low end mixture screw is to lean, I found that all were to lean and adjusted them in, try that first because these 46fx engines are sweet hearts when set up right. I installed mine in a ultra stick fourty and fly it every weekend with out a flaw. also when not in use they tend to gum up in the needle valve area and cause a no start so turn the mixture screw in to bottom then turn it out to the settings bubba has posted and try again. best way to resolve this problem from happening again is to run the engine dry every time after use.

bubbagates

My Feedback: (32)

One thing you will need to remember is the 3/4 setting on the mixture screw will be somewhat rich and may tend to bog the engine a little bit when you snap open the throttle. Leave it like that then set the high speed needle screw for max rpm minus 300 -500 rpm which means you will take it to just when it becomes lean (max rpm) then back it out aprrox 1/8 to 1/4 turn to enrichen it so it will not be lean at altitude. Once the high speed screw is set then lean the mixture screw about 1/8 to 1/4 turn, I suggest no more than 1/8 turns at a time) restart the engine then snap the throttle open and it should transistion to high speed quite quickly. If it bogs, blows a bunch of smoke, then goes to full speed, just lean the mixture screw 1/8 turn more. If it produces no smoke and dies then it's to lean so enrichen it 1/8 turn.

The mixture screw will not need much adjustment as it is quite sensitive but once it is set you will not need to touch it again. Also when setting the high speed screw, make a small adjust and wait a few seconds for the engine to clear before making any new high speed adjustments.

I also agree with Senza, the carb may also be gummed up a bit. Screwing in then out the 2 screws may just clean the seats enough to let the fuel flow and clean it the rest of the way.

I also use Cool Power (green color) with 15% nitro in both of mine. The standard oil mixture for this fuel is 17% but according to OS as long as it is only synthentic oil and not a mix of synthentic and castor the Cool power fuel is fine

I use these settings on the 2 OS 46Ax engines I own and all are very reliable.

Please let us know how you make out...