many problems with engines
 

I have a 2.5 tmaxx it wont start and is not sucking fuel. Problem 2 i bought a sirio tx-18 engine to mount in truck but the piston and sleeve seems to be to tight. When i manually turn the motor over piston pushes sleeve out of cylinder.




purchesed of somebody brand new no refunds please help

RE: many problems with engines
 

When you have a new motor, it will push the sleeve out if you try to turn it with no head on it. Since these are ringless engines, the pinch between the cylinder and piston are what creates the compression required to run.

When you say not sucking fuel, how do you mean, it isn't supposed to suck fuel, it's supposed to get pushed in my exhaust pressure. Have you checked your lines for leaks and tried turning the motor over with your thumb over the exhaust?

RE: many problems with engines
 

An engine sucks the fuel in to the engine as well as the exhaust pressure pushing.

Also give the engine some throttle to help out.

Ryan

RE: many problems with engines
 

yeah with out the head on it will push the sleeve out of the crankcase. Just put the head on and make sure you tighten them the right way and you'll be fine. Also when you decide to break that engine in you can try heating up the engine with a hair dryer and that will alleviate some of the pinch. Now this is when your ready to break in this engine. And as fare as the first question try putting your finger over the exaust stinger and then try starting the engine. This should push some fuel into the carb. And you can also try appling some throttle this will also help get some fuel into the engine.

Or you could try taking off the air cleaner and plugging the carb opening with your finger and trying to start it. This does the same thing as putting your finger over the exaust just instead of pushing the fuel it will cause a vacume and will suck the fuel into the carb. You can also try appling some throttle when doing this. Just make sure your fingers are clean and make sure no foreign debree gets in the carb.

well i hope i helped you in some way

RE: many problems with engines
 

thanx i'll try it today

RE: many problems with engines
 

Yes it will, but very little and actually none at all until it gets running because of the lack of vacuum in the design. It will run extremely lean if allowed to suck only.

RE: many problems with engines
 

Actually i have seen people run there vehicles in races and in normal bashing without the back preesure line from the exaust to the tank. And they say you gain a ton of power and the one guy said he had several gallons through his. Now im not going to do what i just said but yes with the way that 2 strokes work there is some suction and it will run without the line from the exaust to the tank. It can and i have seen it done. And yes it will run lean a little bit lean but not the way that slodsm is describing it. It will run lean but with some little adjustments you can make it work and it wont destroy your engine.

RE: many problems with engines
 

lol when i was a noob and i got my first rc. a rc10gt. i didnt have that fuel line that went in the exhaust. i had only 1 line which went to the carb. i didnt know that there was supposed to be another line until i saw it on the internet. but other then that it ran fine.

RE: many problems with engines
 

I don't quite understand what you mean here. "untill it gets running because of the lack of vacuum in the design."

You do realize the whole point of the venturi design on a carb is to suck fuel and the engine must "get running" in order to provide exhaust pressure as well.

The first few Nitro engines never had exhaust pressure lines. When tuned properly they will never run lean, same with current setups as long as the tank height is not lowered.

Ryan