Help with TRX 2.5, High Idle and High Heat

[Dreadx]

Hello, I have a Tmaxx 4910 that I bought used a few months ago. It has the TRX 2.5 engine. The guy said he put only about 5 tanks of fuel through the motor after break in and then parked it. Based on the condition of the truck and the engine I think this is true. The engine had been treated with after run oil and was not frozen. I did sit for unused for a few years. I replaced the dry rotted tires and malfunctioning radio. Then did a complete tear down and cleaning of the engine. I have had Nitro cars before so the engine disassembly and cleaning went smooth.

The engine wont idle at a decent speed no matter what. The carb gap is correct and its set to a rich factory tune. The compression seems good. No matter how much I reduce the idle via the screw it will run hard. I am thinking it has to be an air leak. The fuel tank and lines are air tight and has a brand new exhaust and a new back-plate and back-plate seal. The head gasket looks good and glow plug is new and the gasket is intact. Any ideas or help would be greatly appreciated. Here is a video of the truck running

 

[cbaker65]

You need to start tuning the engine ,the gap doesn't matter at this point in time because when you start leaning the HSN .
you will have to adjust the idle gap accordingly!...meaning you may have to re-adjust it
if it starts to idle too high or too low!...

 

[Rolex]

Above post is correct. Once it's been run through it's basic break-in tanks it will NOT run with factory settings. When the LSN is leaned, the idle must also be lowered. The HSN is for WOT running.
Do you have the manual?

 

[Certified Mike]

The idle gap should be set to approx 1mm. and 'set to forget'. The idle gap is more of a mechanical setting based on the idea that your radio and physical servo setting does not control your idle setting. Setting it to 1 mm. Is the first place to start. After that, as above states, the tuning is likely where your issues lie.
To avoid any confusion regarding the high temp... To start, you should be tuning without a body in place. After you get it back to running right, start running with your body on and check your temps often to be sure this is not an issue of poor air flow thru the body itself.
After a rebuild, I recommend treating your engine as tho it is new and needs to be brought thru a break in session.
Good luck!

 

[Rolex]

The of legal

Not sure what that was supposed to mean. Auto-correct?

 

[Certified Mike]

'The idle gap'
Thank you! I REALLY don't appreciate the way this phone 'corrects' what I say, despite it being spelled correctly because it doesn't understand the terminology. This happens a LOT to me and I often miss it. I am sorry for the confusion.
================================
I corrected it for you...
Rolex

 

[Certified Mike]

Lol! Thank you again! I took the time to explain and then forgot to edit! Go me!!!! Lol!

 

[Rolex]

Lol! Thank you again! I took the time to explain and then forgot to edit! Go me!!!! Lol!

Not a problem. You're not the only passenger on the short bus...but then....it's not THIS one, is it?

 

[Certified Mike]

That could explain why sometimes I feel like a S**T HEAD!!!! Lol!!!

 

[cbaker65]

I've gotten stuff that was second hand before in nitro cars!....

The stuff that I got was from people who failed to tune the engine after break in!....LOL I think in my opinion is
the best stuff to get because its basicly still like new stuff.
For one thing ,LOL ....its not going to run very well with a filthy rich carb setting in which the people latterly
give up on the rc.

I have in my possession a nearly new MMgt. that the tune was untouched by someone that did not
know what they were doing!

Total cost to me....NOTHING!

 

[Rolex]

Not only are the carb settings factory rich, but old fuel is gummed up in there.
On the bright side, if it was never tuned, it was never run hot and lean.

 

[Dreadx]

Got it fixed. Turns out the carb needed a rebuild. I got a rebuild kit and replaced all of the o-rings, now its running right as rain. Thank you all for the help.

 

[Certified Mike]

Glad it's all fixed up!!!

 

[Rolex]

Glad it's all fixed up!!!

Yeah! Now get out there and break something!