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Ah Clem
06-01-2007, 03:22 PM
I recently purchased a Raptor .30 with a Thunder Tiger .39 installed (brand new ARF).

I started out with 30% nitro fuel, as that is what I had for my OS .50 Hyper. The motor started easily and idled with no problem, from the beginning, but I could not get the top end to richen up. There is a lack of smoke and a definite clean (lean) two cycle sound when I punch it).

I switched to 15% fuel to see if that would make a difference, but it has not changed things much.

The motor/muffler is actually hot/smokey when I land.

Low end and mid-range seem to be rich enough, but high end is a problem. Transition from low to high throttle is very good-no loading up or hesitating.

I have swapped out all the fuel lines, and will be checking for leaks at the head and backplate, but I do not think that I will find anything.

I am about ready to take the carb apart to look for obstructions.

Is this a common problem? The motor runs fine, but will not last this way. I am wondering if the carburator is like the old Super Tigers, where the bottom end mixture can effect the top end (those things used to drive me crazy). OS carbs used to be the best.

Back up plans are to try to retrofit an OS .40 FSR carb, or replace the motor with an OS (I would like to avoid that last one, if I can)

I should think that the TT carb will work, and that I am just missing something.

Any assistance would be greatly appreciated.


Thank you all in advance.

chevpro
06-05-2007, 05:34 PM
I'm running a carb from an OS46fxh on mine. First tuning was tough, but been running good ever since.

Todd

Ah Clem
06-05-2007, 06:32 PM
Chevpro,

Was the OS46fxh carb a direct fit?

I finally go the Thunder Tiger carb working, with some help from several people on the RCGroups forum. I also took it apart to see how it was made.

Why Thunder Tiger copied a Super Tigre design, instead of an OS design is beyond me.

BarracudaHockey
06-06-2007, 12:03 PM
What you are experiencing is exactly why people prefer os 37s, carb consistency.

chevpro
06-06-2007, 02:37 PM
The 46fx carb was a direct fit. No mods needed. :D

Todd

bmlasater
06-22-2007, 11:53 PM
fwiw..

Change the fuel tubing in the tank!...This tubing is not thick walled enough to avoid pinching down when fuel is pulled through it...Replace ALL the tubing with medium Aerotrend..Start at 3 1/2 turns open on the main, keep the idle needle rich enough that the motor will barely keeep running with a full tang...Lean as necessary, but be careful...much under 3 turns and you're getting lean...This is a good motor if tuned correctly..Runs best on 30% nitro, however...

John.

bmlasater
06-22-2007, 11:53 PM
fwiw..

Change the fuel tubing in the tank!...This tubing is not thick walled enough to avoid pinching down when fuel is pulled through it...Replace ALL the tubing with medium Aerotrend..Start at 3 1/2 turns open on the main, keep the idle needle rich enough that the motor will barely keeep running with a full tang...Lean as necessary, but be careful...much under 3 turns and you're getting lean...This is a good motor if tuned correctly..Runs best on 30% nitro, however...

John.