New to helis, really need some engine troubleshooting!

[In2JeepN]

Hey all, new to heli's and the site. Im not new to R/C or nitro engines, have been playing with nitros for about 5 years now, but I am truly at a loss with this TT39 engine in my Raptor 30V2.

It runs hot, VERY hot. Hot like 280+ on my infrared gauge....it melted my exhaust deflector (which I have never seen happen before) in only 10 tanks of fuel, and the muffler is so hot that it has actually melted the rib of the frame nearby. The thing I cant understand is that I am running this engine SOO rich that the entire flying field has a smoke haze hanging over it, no joke. If the heli is sitting on the ground and I spool it up so that it is light on the skids, the heli cant even be seen, other than the blade tips and the tail rotor...lol it actually almost looks like the heli is on fire.

I took it to a very experienced guy here in the Toronto area (actually did a couple of hours of lessons as well) and he set up the mix a little better than I could, I am too inexperienced to be able to give it more than just hover throttle to get it tuned properly. While he was flying it and setting it up, the mix was changing on him and he said he thought it had a small air leak as it was hot even tho he set it a little rich. The next day I took it out myself, and it was super rich, richer than I think he had it, and hot. I have been making this thing richer and richer and I finally have it around 200 now, but I am just shy of 3.5 turns out on the high speed, which is giving me about 9-11 minutes of flight time (not sure what I should expect for flight times with a tuned motor?)

I have had this thing torn completely apart looking for air leaks 3 times now, and cant find anything...pressurized the tank and all lines underwater looking for bubbles, nothin...have taken the head, carb, and backplate off to make sure that all the surfaces are smooth/sealing/etc and cant find a THING wrong....any ideas???

One other thing to mention (sorry, this post is huge!) is that even with the fan tightened right down (just did it again last night to make sure) it looks like it touches the front bearing fine, but I still have a little end play in the crank, maybe not quite 1mm or so. It looks like the front bearing is allowing the play, between the inner race and outer race?

Anyways, I may scrap this TT and just get an OS like I should have done from the start...this thing may be crap now anyways, I cant even get the damn sleeve out of it, and the whole piston/sleeve are just black like I have never seen before. Does anyone have any ideas for me before I go blow a bunch of money? I would really like this to last a couple of gallons just so I can finish learning my nose in hovers and get into some basic FF if I can. Thanks in advance, sorry for the xtra large post everyone!

Tom

[SC Raptorman]

Sounds like you need to adjust the low needle , the low needle adjusts the fuel mixture to about 75% of the carb range and the high neetle does the last 25% or wide open . Hope this helps . :noteworthy

[Gunner]

Make sure you have a head gasket installed. I had a leak around the head. Bolts were tight, couldn't figure out why the engine ran so hot. After taking it out, checking everything, putting it back, still had a hot running engine. Determined that the leak was coming from around the head. After taking the head off one more time, I realized that there was no head gasket. It came that way from the factory. When I contacted OS, they sent me 3 free gasket sets. Once I installed the head gasket (I put a new bottom gasket on also), everything runs fine. Check it out, the head gasket may be your problem.

[In2JeepN]

Make sure you have a head gasket installed. I had a leak around the head. Bolts were tight, couldn't figure out why the engine ran so hot. After taking it out, checking everything, putting it back, still had a hot running engine. Determined that the leak was coming from around the head. After taking the head off one more time, I realized that there was no head gasket. It came that way from the factory. When I contacted OS, they sent me 3 free gasket sets. Once I installed the head gasket (I put a new bottom gasket on also), everything runs fine. Check it out, the head gasket may be your problem.

Damn Gunner I never even thought of that! I am at work right now so I cant say for sure, but now that you have mentioned that I dont remember seeing the gasket on this motor when I pulled the head...and that really is what made your engine run hot? weird... Thanks tho, I will sure check that tonight!

Tom

[Gunner]

In1j, The gasket is brass or copper and it may be on there. So look for a ring that looks brass in color. It may not be apparent that a gasket is in place because it is so thin that you can't tell. I took a sewing needle and picked at the inside edge to get it loose. Anything larger, like a small screwdriver, is too big. At least take it off and look at it. At any rate, my pre-flight check now involves making sure the head bolts are tight.

[In2JeepN]

In1j, The gasket is brass or copper and it may be on there. So look for a ring that looks brass in color. It may not be apparent that a gasket is in place because it is so thin that you can't tell.
Actually the head gasket is this motor is aluminum, silver in color, which is the reason I didnt remember seeing one. I have rebuilt many nitro engines over the years, and as you said Gunner, they are usually brass or copper...this is the first aluminum I have seen, but regardless its on there! :bomb:

Anyways, I digress, I finally got fed up with this thing, I am thoroughly stumped with it so I bit the bullet and bought the OS37 engine, which I will break in this weekend :mrgreen: My LHS is curious about the TT engine now too, so I told them that I would bring it to them so they could tinker and see if THEY can find whats wrong with it, I will update if I/they find anything so that it may benefit others. Thanks for the help guys!

Tom

[rpchus]

Hey, I have a TT39 that is giving me fits trying to fine tune. I just about had it, but had an unexpected run-in with the ground not long ago. Now, without changing any of the mechanical or radio settings, it is giving me problems again.
So, how well do you like your OS-37? I've been thinking along that route, but don't know if I can use the TT upgrade pipe (pv0102) with the OS-37 - assuming now that I can, just haven't checked into it yet.

[Ah Clem]

I am interested in how the OS .37 compares from a power standpoint.

I too, had trouble with my Thunder Tiger .39 running hot. In my case, I could not get it to run rich enough (it sounds like a different problem from the one you are having).

I got help from several people on several forums. Based on this advice, I set the main needle back to three turns (is was out to four) and the idle needle out to four turns. For the first time, I could get the motor to four cycle so rich that I could not get the helicopter to hover. I leaned out the high end and until it had a rich two cycle and gradually leaned the low end for a good idle and a fair transition. I had to richen up the high speed needle a bit after leaning the idle.

Carb design is like a Super Tiger. No nearly as good as an OS.

What fuel are you running?