Revo 2.5 running hot, don't know why

[vwdave]

Posted this on the Traxxas forum, want to see what info I can get here. My 2.5 Revo has decided to run hot (around 280 with tempgun). I've used the tuning guide and leaned out, no help. Then went slightly rich and still to hot. I've ran it like that twice, hope it didn't cook the engine. I first noticed it because the truck was running fine then just slowed. Put the temp gun on it and got a 290 reading. Of course shut ti off right away and let it cool down. Doesn't seen to have a leak around the header. Could the resonator cause it? The exhaust (resonator) reads 200 when I check it. What is the best way to check a Nitro motor for air leaks?

 

[outlawbrett]

what i wud is just pop the motor out and start by taking the carb off an checkin orings. make sure there not torn anywhere. specially the one down the throat of the motor, where the carb slides in. gets some RVT silicone, i use black, or u can use copper too, and spread it around the base of the carb were the top oring is. u dont need alot. also take put on both sides of crimp nut(where u tighten down carb) take off ur ez start or pullstart and then take off backplate and do the same with silicone on both. take off exhaust header an put some there also. make sure oring is good. make sure ur head bolts are tight. exhaust rubber coupler isnt ripped. tear down ur carb an check orings on fuel outlet an HSN. u can use a product called green slime on the needles to help it seal. the resonator cud be plugged, but doubt it. i usually dont test my motors too see if there leaking, i normally just seal them before i break them in. but u can take a piece of clean fuel hose an attach it to fuel outlet on carb. plug carb throat an exhaust with ur fingers or whatever. blow into the hose an use soapy water an brush around the carb, exhaust, backplate, bottom of head. I've seen it done that way.

 

[Rolex]

Before going through all that, overheating is usually a tuning issue.
Try richening your LSN slightly. Too lean on the LSN and the HSN adjustments won't do much to cool it down.
If it's not the tune it could be too tight of a mesh between the pinion and spur or a bad bearing causing more resistance.

 

[hulkmaxx]

What the others said. But it never hurts to re seal your engine. Copper seal works best for me. It sounds like an air leak to me, check fuel lines to see if there are air bubbles in the line going to carb that usually meens an air leak.

 

[joshman1204]

Sounds like a bad tune to me ... an air leak will usually lead to temps much higher than 280. Follow rolexs advice for leaning the needles and see what that does.

 

[REVO-5309]

If its been running well without any recent needle changes I'm going with extra resistance somewhere

 

[pitluver52]

+1 revo 5309