I need help with my engine , it does not like nitro i run 5% in it flys fine but wont drop back to idle for agers sits there barking at me and is very hard to tune does not peak before going lean have been trying different top and bottom end tuning with no result oil is also black coming out exhaust this is a new motor with about 20 flights , pulled it down today every thing seems ok inside.i have two other planes and none of them give me any problems
please help with some tips please.

G'day Mate,
Need some more info, what plug, what prop, what oil in fuel? Every TT Pro 46 I have seen run's great with 5 to 10% nitro, coolpower oil, 11x6 prop & OS #8 plug. What are you using?

Allan, Mick,


I don't think all-synthetic CoolPower oil is the best choice for this engine...

Even Morgan Fuels, its manufacturer, recommend Omega fuels for ABC/ABN type engines, which the TT Pro is.


The prop and glow-plug recommendation is spot-on, however.

About the phenomenon; I have seen this happen; you throttle down and the engine hangs at 4,000-4,500 RPM for some 10 seconds, before dropping to idle...

I think the engine I saw do this was too rich on the low-end mixture.

In most cases, this only causes a fading idle and a 'burbly' recovery to max RPM (if it eventually happens), but that engine had that 'hanging' before drop-down.


Mick; it certainly is not a nitro related problem!

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It sounds as though someone either forgot to put in the head gasket, or they removed it before you got to it. The engine sounds over compressed. I would check to see that there is a head gasket (shim) in place. And I wouldn't run it much as it is until I knew one way or the other.

Highly over compressed engines will never get to their peak rpm because the timing is too far advanced.

You champion your right there was no shim or head gasket there when i pulled it down yesterday makes perfect sense thanks heaps will go serching for one.

You can cut them fron beer or soda aluminum cans with a small circle cutter you may need 2 or 3 thick the stuff is about .005 or .005
martin

[quote]ORIGINAL: dieseldan

You can cut them fron beer or soda aluminum cans with a small circle cutter you may need 2 or 3 the stuff is about .004 or .005 thick
martin

I don't recall my TT46Pro having a head-gasket -- mind you, it's been a while since I pulled it down to do the bearings.

Sorry for not mentioning the size of it (thunder tiger pro 91) i looked in the manual and it is supposed to have a shim in the top and gasket in the rear seal as well both are missing they are sold as one part PN0194 gasket set ,local hobby garage also said to use coke can as well but for one i dont have a circle cutter and i dont know what part of the head it goes yet. will go see the bloke i buy my parts from tommorow he is a jack of all trades.
thanks for all your advise will let you know once i get a gasket of soughts in there.
The motor goes in my pheonix extra 300 its a 46 size plane and was ok with the motor running bad but cant wait till its tweaked.

try www.ehobbies.com for you tt parts. they took care of me when i needed it for my tt.