dumb 2.5 question

[th3j3sus]

i bought a trx 2.5 off craigslist and i can't seem to get it to start, i feel it doesn't have much compression but i am also comparing it to a 5.9 big block. my main question is that i bought a new piston and sleeve along with the o-ring kit for the carb, should i get anything else for rebuilding this motor and is there any tips for rebuilding it? i set everything to factory and it seems to wanna start but bogs instantly. installed a new glowplug yesterday but it didnt seem to help much. Its retarded but to get it to fire yesterday i pretty much had to flood the engine to the point that fuel was spitting out the carb. i left the glow plug on for 20 sec n then tried to start it. It fired up but went full throttle and then stalled. the fuel tank and lines are in good working order.

 

[mtaylortank]

You might need to seel the engine, there might be an air leak...

 

[Snook Man]

Were you sure to install the piston in the correct direction? Cutout on the piston skirt faces the front/carb side of the engine. The oil hole in the bottom of the con rod also should face the front.

 

[th3j3sus]

I did not check for leaks, what would be best? Soap and water? I didnt install the new piston and sleeve yet thinkin this may be a easy fix n jus have that as a spare. I dont see fuel leaking out anywhere around the carb and exaust port.

 

[ckblood05]

i just sealed my 3.3. i used high temp rtv gasket sealer. i put it around the carb, the backplate, the header pipe where it bolts to the engine and the fuel inlet port and hsn needle valve.

heres a good video on how to check for air leaks-

[ame="http://www.youtube.com/watch?v=epEGetU7NFU"]How to test a nitro engine for air leaks - YouTube[/ame]

 

[th3j3sus]

thanks, i will tackle that tomorrow. i dont exactly know what you mean with sealing the lsn, how would i go by doing that?

 

[th3j3sus]

So i was watching a video on youtube from thetoys about sealing a engine n he was using some poop he was calling green goop. What is it? Lol he used it to seal the lsn and whatnot

 

[Metalhead Matt]

Green Slime. Team Associated makes some.

 

[ckblood05]

yea, most people just use rtv gasket sealent. you can get it at autozone, o'reily's, advance autoparts, etc....

 

[2revo1maxx]

Lucky seven works very well, and you don't have to dis-assemble the engine to use it.

 

[th3j3sus]

Is there any kinda stuff i could pick up at a autopart place for thethe lsn needle along with the gasket seal i need?

 

[ckblood05]

Is there any kinda stuff i could pick up at a autopart place for thethe lsn needle along with the gasket seal i need?

yes just get some high temp rtv silicone gasket sealent.

 

[th3j3sus]

And i just put that on the threads of the lsn when i pull it out?

 

[2revo1maxx]

No! LOL, Use di-electric grease or associated green slime on needle o-rings.
The rtv is for sealing the backplate, carb thoat, and carb pinch bolt.

 

[th3j3sus]

So i put a new sleeve and piston in and sealed the entire engine along with a oring kit from traxxas for the carb. i tried to start it and it would not fire. the glow plug is new, it sounds like it wants to but just can't. Can anyone help me out with this?

 

[2revo1maxx]

Make sre the needles are at default and warm it up with a hair dryer first.