I bought this used TT .46 pro, and am having problems.

It is getting hot, even at rich settings.

It gets just above 300 after landing and running.

I can hear it get hot on the ground......it will rev out quick, get hot, and lose rpm.

What could cause this, of course it is not the obvious to lean. Is this symtoms of a old worn out engine?

Maybe it could be something else alltogether?????????

It is inverted on a seagull pc9

Thanks for any help

871

Is it inside a cowl, or out? What kind of fuel are you using, and which plug is in it? How about prop, are you running something larger or smaller than recommended?

in cowl, 15% os#8. 10x6 prop was reccomended

Thanks

what sort of 15% fuel? I understand that some of the car fuels have low oil content..

Are you using one of those infra-red non-contact heat guns?

If so, just ignore that reading -- the numbers they return are affected by so many factors that they're only useful for making relative readings rather than absolute ones (ie: if your engine is running hotter or colder than it was yesterday).

If your engine is cowled it could be that you've got insufficient exit area for the cooling air. The rule of thumb states that the hole(s) where the air comes out of the cowl should be at least twice (and preferably three-times) the area of the hole where the cold air comes in.

Can you post a picture of your setup?

Got one that does pretty much the exact same thing. Ran it un-cowled. Tune it rich on the ground and put it in the air and it gets hot, tightens up, and slows down almost immediately. Took an OS off to try this engine so I know the fuel system was good. Engine looks and turns over perfect and still has a decent amount of pinch left in it. Right now its a shelf queen.

What fuel were you using?

It's my bet it was something without any castor in it -- right?

If it was CoolPower or some other fuel with a 100% synthetic lubricant then that's likely your problem.

Also, in its stock form it's been my experience that the TT46Pro runs best with nitro levels of 5%-10% rather than anything higher.

I agree...it might be inadequate air flow through the cowl? Have you tried flying it without the cowl?

Also, check all the screws...you might have an air leak at the backplate or a loose head? And make sure the carb is fully seated in the case and the O ring is still there and not damaged.

Also, I think maybe the 10X6 is a little small for that engine?

Actually the TT46Pro turns a 10x6 very nicely.

In fact, they'll turn almost anything from a 10x6 through to a 12.25x3.75 with no problems at all.

I agree...I have 3 TT .46's [8D]
Maybe in this case, a lighter prop load like a 10X6 is o.k. until he gets the heating problem figured out?
Afterward, I would use either a 10X7 APC in that airframe, or maybe an 11X5 if I wanted pulling power.

Another question for the O.P.
Which muffler are you using?

Temp gauge, Oh goody. There are no specs on the temp ranges for these engines. 300 degrees, whatever. I usually tell people to avoid those with a temp gun since they are pointing that thing at an item and it tells you nothing. Hows the airflow through the cowl.

I did notice you said it was inverted. if the fuel tank is mounted it the stock position, that is 1st on the list of problems and until you fix it, you will continue to have problems that a temp gauge willnot fix

I hear ya about the temp gauge, I bought it after I could not figure out why this thing would run great on the ground, but then slow down and lose power after 3-4 min in the air.

Any richer on the needle, and the plane will not takeoff!

I tightened the head bolts

I run 15% nitro 20% 100%syn oil

I bought it used, and it has a swept bact after market pipe on it

thanks

871

Oh yea, the cowl is only a half cowl, and the majority of the motor is exposed so I have great airflow

We had a problem where the fuel nipple in the muffler was almost completely plugged and after a few minutes it started pulling a vacuum in the tank and would lean out and get hot. Took a while to find that one and it was the nipple that came in the factory muffler. After running a drill bit through the nipple, the engine ran great.

Can you pull the muffler and look to see if the sleeve is properly lined up in the case? Perhaps it's been rotated or something?

Jezmo had a good suggestion, too - perhaps the muffler pressure nipple is plugged and it isn't breathing properly.

The TT46 carb has a screw and washer on the right side, about half way down the throat housing, that has been known to loosen up and cause the engine to run lean. Make sure it's tight.

Only thing I got left is that maybe the non-stock muffler is not providing enough tank pressure?

Thanks guys for giving me so much to check. I checked the small flathead screw, and it was a bit loose. also, the backplate bolts were just snug, so I tightened them.

I also stripped my carb, and there was a little piece of goo in the needle valve area.

Checked my pressure fitting on the pipe, and it was ok

I am going to bring another muffler to try at the field if all that does not work!

Hopefully this stuff will work, I will know tomorrow!

871

How did I know that'd be the case? :-)

You're killing that engine with 100% synthetic oil -- you *MUST* use some castor if you want it to last and perform reliably. It won't take much to change to a fuel with at least some castor in it -- try some 10% Omega. You might be very surprised at the results.

Sounds like a Mac's pipe perhaps? Try ditching that and fitting a Tower/GMS47 muffler. These will add up to 1000 RPMs over the stock TT muffler and make for a very sweet-running engine.

I will try a change in fuel too!

STOP FOOLING AROUND WITH ALL THAT STUFF, WHERE IS THE FUEL TANK LOCATED??? IF IT IS MOUNTED IN THE STOCK POSITION, THAT IS YOUR PROBLEM

Thanks cyclic, yea the tank has been lowered.....and replaced with a dubro 12 oz side mounted.

what specs should I make sure the tank position is in?

Thanks

871

CL of the tank should be in line with the carb.

Okay, how about this logic. You have a used 46pro in a 63inch wing plane at about 6lbs. Along with your altitude, that engine is performing closer to a .30 pulling a very heavy load around.

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