2.5R won't hold a tune...

I'd check the O-ring on the fuel tank. Revo's are known to chew those from time-to-time and it'll cause the problems you are describing. Best bet may to get a tank rebuild kit and give it a whirl.

Ok, first and easiest thing to do is to do like th Monkey says and check the o-ring under the cap on the tank. If it's blue replace it with the new orange ones #5362. If it's orange, look it over real good to make sure it's not cut. Moving on:

1. what kind of temps are you getting?
2. with the pinch and new rod, did you run through break-in again?
3. Have you tried going back to stock settings and working from there?
4. New seals doesn't neccessarily mean the engines sealed good, check for leaks using WD-40
5. When you say you are adjusting, how much are you adjusting? 1/8th turn, 1/12th turn, 1/4, 1/2? Remember these are small engines and small adjustments go a long way, I recommend thinking of the needle as a clock and using 1 hour (1/12th) adjustments
6. How good is the compression? warm, not cold
7. What glow plug are you using and how old is it?

Answer these question and you can help us help you!

I had the same problems not to long ago. I thought it was a compression issue so i sealed everything with silicon. Then as the guys above mensioned replaced the gas tank seal. Then i met a guy at the lhs that said the traxxas carb is a P.O.S. so i bought a o.s. that he said was the best. 50$ later and it runs like a champ. So i recomend a carb swap. Worked for me so if you get desprate try it.

Bryson Molesky said:

I had the same problems not to long ago. I thought it was a compression issue so i sealed everything with silicon. Then as the guys above mensioned replaced the gas tank seal. Then i met a guy at the lhs that said the traxxas carb is a P.O.S. so i bought a o.s. that he said was the best. 50$ later and it runs like a champ. So i recomend a carb swap. Worked for me so if you get desprate try it.

Click to expand...

Would help if ya specified the OS mill you got it from!!! Interesting mod. Never heard that. Than again, only had two Traxxas rides.

Thanks for the input. I did upgrade to the orange tank seal and have checked it for cuts and nicks.

Jetmech
I am trying to keep the temps around 240 and I did re break-in the motor. with RayA's recomended break in process. I absolutely go to the stock settings then work back from there. And when I am at whits end I go to stock and start over. I am using a new MC9 plug and I have changed it out occasionally with another new one to see if there are differneces in performance or tune (None). My adjustments are typically 1/8-1/12 turn for either needle then run look and listen to performance. The compression when warm is very good now that the sleeve has been pinched. That leaves the WD40 test you mentioned...What would I do to perform it?

M

I have looked into getting the carb and I think it may be my next option a 10D and 11K have been posted..

Well, your plug isn't helping. MC-9 is a cold plug, you should be running Hot plugs, either MC-59's, LC3's or the Traxxas plug. WD-40 goes as so:
With the engine running, spray WD-40 on selected areas (the carb base, the backplate, under the head) one at a time. Spray a liberal amount. If the engine quits or starts to sputter, you've found a potential source for a leak.