Tmaxx Engine races

[mrcknlps]

I finnaly go the 2.5R engine running, but I flipped the truck and the engine started to race and would not shut off. what makes this happen???



tony

 

[Zdragon71]

Maybe the throttle servo stuck in wide open position or went bad at time of crash. The servo is the only thing that can open carb body full throttle and when your batteries are dead or the servo goes bad it will go WOT on you for no reason. Check batteries first.

 

[*madmaxx3.3*]

This happened to me one time only to find the engine mount screws were loose.

 

[SchrodeMode]

How high did it rev? Being upside down leans the engine out and will cause it to race, did it fix itself when you flipped it back onto it's wheels?

 

[mrcknlps]

Ok I pulled off the Engine and there was a hole worn on the botton of the engine. I replaced the old 2.5 Engine with a New 3.3 engine, now the Engine gets stuck at the top, After I pulled the engine off and pulled the heat sink off. I got it working, the piston moves up and down. But when I put the heat sink back on it still gets stuck on top. What is causing this???

Tony

 

[Nitro4910]

You need to preheat the engine during break in with a hair dryer, the pinch in the 3.3 is really tight on a new engine.

 

[REVO-5309]

all new engines are tight. my lrp z.28r is still tight and get stuck and iv put half a gallon through it.

 

[Zdragon71]

+1 On the pre heat with hair dryer before trying to start your 3.3. Hell i still do it on every new start up of my 2.5R after 2 1/2 gallons of fuel. It just causes it to loosen the pinch up enough to start alot easier. Sometimes during breakin it will get stuck tdc and heating with dryer is the only way to unfreeze it for starting without breaking the rod! After every run you need to turn flywheel by hand to bottom dead center also. This will help in the matter of getting stuck tdc when engine cools down between runs.