Hi...I have been trying to get this carb equipped engine dialed in  ..running tongue muffler,10 x 6....runs good on high rpm..but won't idle without dying...Does the G21 46 have a chromed steel liner and aluminum piston with a single ring. If so...would this be safe to use synthetic lube fuel?  I know it has a ball bearing crank/

I am using a fuel I suspect may be the prob....5% nitro,,,20% all castor....OK...Is the all castor the prob? I was told yes..of course I was also told anything other than all castor would cause overheating and other nasty things and a ruined engine...
So,,,,what is the answer from the gallery...I figure among so large a group I will achieve enlightment.

Thanks....next round is on me...

joe

Hi...I have been trying to get this carb equipped engine dialed in  ..running tongue muffler,10 x 6....runs good on high rpm..but won't idle without dying...Does the G21 46 have a chromed steel liner and aluminum piston with a single ring. If so...would this be safe to use synthetic lube fuel?  I know it has a ball bearing crank/

I am using a fuel I suspect may be the prob....5% nitro,,,20% all castor....OK...Is the all castor the prob? I was told yes..of course I was also told anything other than all castor would cause overheating and other nasty things and a ruined engine...
So,,,,what is the answer from the gallery...I figure among so large a group I will achieve enlightment.

Thanks....next round is on me...

joe

So I assume you are running a throttle on purpose. Low idle problems can be due to several things, one is that maybe you are trying to idle too low an rpm, the other is that a larger diameter prop (and heavier) will give you a better flywheel effect. Another benefit of a larger diameter prop is that if you also have a little less pitch, a higher rpm will still give a reasonable flight speed.

Next would be glow plugs---it needs to stay lit at low rpm even though less heat is being made---you might try a hotter plug or one with an idle bar.

Finally it could be the carb. Normally in CL we have that big open venturi hole, so small airleaks don't really amount to too much. However when you throttle down an RC engine, now you have only a tiny little opening to supply the airflow, so small leaks are proportionally worse. So check that the carb is sealed where it plugs into the crankcase--the o-ring can sometimes be pretty dried out in an old engine. Doesn't hurt to make sure the needle is  also sealed against air leaks. I assume you have been playing with the low speed needle or air bleed adjustment. So just in case you aren't aware, you set the high needle first, then the idle adjustment. The idle adjustment can be a pain because it can be difficult to do with the prop turning--so usually and safely it is best done with engine off--but as you know, that means you got to crank it up again, and again, and.........



added---because it is a ST 46 I assumed it is been already broken in. If for some reason this is not true, then usually the engine needs to be broken in with ring all wrung in before idle can be set reliably.

OK..thx for all the info....so running synthetic blend will not harm this older engine...Maybe a little higher nitro and a hotter plug are the ticket..

  Far from hurting it, I think you need some synthetic to keep the ring loose in the groove. And they really come alive with nitro.

     I am a little surprised at your prop selection, if we are talking C/L. I ran 12-5W, 12-6, 13-6, and even a 13-5. For really light airplanes you can go down in the 11's.

     Brett

I have a NIB T&L G.21 .46 (sorry, Brett, it's not a cherry...but it's got a rilly good ring!), and I think Tom wants me to run 25% castor forever. I'll start with 10-29, and switch to 10-22. Meanwhile, Alan Resinger told me last summer that he's running YS20/20 in both his Stalker .66 (.67?) and the G.21 .46.

Personally, I can't see running that much nitro without stepping up to some sort of epoxy finish, which I'm not willing to do at this point (crash too much).  Steve

Hi Steve

Run what make ya happy, but all castor will 99 to 100% of the time stick the ring in the groove and kill off the engine power and run. seen it happen way too many times, I explain it in detail in the Engine article at the opening of this page.
It also does bad thing to the top of the rod :-(

Regards
Randy

Matter of interest is there any particular reason you are using an R/C carb on a controline model or did I miss something.
 First thing I would do is toss the carb in your spare parts drawer and get a venturi  assembly from one of the many people that make and sel them on this board, I really believe your running problems will be over at that stage.