Got a TT Pro .46 in my space walker 2. Engine is mounted almost 180 but not quite. The travel of the throttle arm on the engine to me
doesn't seem as much as say an OS engine. Was having some problems with it at the field. Screwed with the high needle, leaned out the low end about an 1/8 turn. While flying the plane, had it at low throttle and then went to full and the engine quit giving me a very nice dead stick. I'm gonna have to take the cowl off and re-check the throttle linkage as the rod may be hitting the cowl when I give full throttle. Engine just don't seem to have the "nads" it had a month ago. Running Cool Power 15% nitro in it. I even changed glow plugs and it seems to be cutting out a bit. The plug is an OS A3 (only new one I got left).

Dave...

Base setting for TT46Pro is about 2.5 turns out for the HSN and about 1.5 turns out for the LSN (carb must be closed), its a base only and gets you to a better start for tuning. If your engine cuts abruptly when you throttle up then the low end is probaby too lean. Another easy way to test for LSN is to let her run on idle then do the pinch test, pinch the fuel tubing and see how the engine quits. If it picks up by a fair before quitting bit then its too rich, if it drops RPMs before it quits then its too lean.

If it dies suddenly when going from idle to open your idle mix may be too lean (the little screw inside the barrel). Turn it about 30º counter clockwise.

The manual has good instructions on how to adjust the idle and full throttle mixes. It's a good little engine when you get it set. You are correct that it has a shorter throw between closed and full open. But it still goes full range and you can adjust the servo linkage (or set the travel on a computer radio) so that you still get the same sensitivity of the OS.

I sucked some dirt (oops) and must have missed some. Lost compression & found the cylinder scoured. I sent my .46 back for repair (it was two years old) TT replaced the piston & sleeve free, even though I admitted full responsibility.

low end could also possibly be way to rich. mine did that at one point. it would go real real rich on the bottom end, load up, then die when i popped throttle to fast

TT .46 Pro --- my favorite 46 size engine (got 5 of the little rascals) [sm=thumbup.gif].

Mine usually run 2 - 2 1/4 turns open on the HSN. LSN setting is variable, but usually 1 - 1 1/2 turns open from bottom, with the throttle closed.


In your case, we need more info --- you can do a few tests to help us.

First -- get your linkage sorted out. Next, peak the engine at full throttle with the HSN & back off a couple of clicks (should be somewhere near 2 turns open). Close the throttle & let it run at idle (ensure correct throttle trim setting).

Does it idle at all?

If it will idle, does it slowly begin to stumble & then die, or does it just die away at idle without stumbling?

If you advance the throttle smoothly from a prolonged period at idle, does it quit sharply, or does it sputter a bit and quit?

If it idles without stumbling & slowly dieing, & then quits sharply upon opening the throttle, the LSN setting is too lean. Open it (anti-clockwise) in 1/8 turn increments until the engine will accelerate smoothly from a long idle. Reset the HSN & do the whole test procedure again.

If it won't idle at all, the LSN is probably much too lean -- open it (anti-clockwise) in 1/4 turn increments until it will run at idle. Reset the HSN & go to idle. If it then stumbles at idle, follow the procedure above. If it idles OK, but dies away as you open the throttle smoothly, it is still too lean. Open the LSN (anti-clockwise) in 1/8 turn increments until it smoothly transitions to full throttle. Reset the HSN & do the idle test again.

If it idles & slowly stumbles & quits, the LSN is too rich. Close the LSN in 1/8 turn increments until it will accelerate smoothly from idle. Re-set the HSN & repeat the idle test.

Remember that both HSN & LSN settings are interactive changeing one will affect the other to some extent.

Ooops!

Your engine is out of tune and if it is inverted or a few degrees off and your fuel tank is in its original slot, your compounding the problem and no matter how well you think your engine is dialed in, unless you lower the tank, your going to have problems.

I have several glows of all sizes and inverted and no deadsticks in a few years, its not a gift, I just pay attention. If you want a perfectly tuned engine. Then while the engine is at an idle, remove the fuel line from the carb or pinch off the fuel line. Listen to the rpms as the engine quits running.

If the rpms increase, your low end setting is to rich. If the rpms just go down and quit. to lean. I set mine for a very slight increase. Once set, you should not have to mess with the low end again unless some other thing happens or a change of season.

I can be this easy.

Thanx all! Going to take the cowl off and check the throttle linkage first. Get that squared away. I will start fiddling with the needles next. The engine ran real good a few months ago with no problems on transition from low to high. Then, the weather got really hot and I had to lean out the high end a bit. Also gonna re-check the tank position too whilst I'm in there along with all the servo screws etc.
Might as well do some preventive maint. once I have it apart. Which is what you should be doing anyways every so often.

Dave...