engine high temp

[avelciario]

Hello guys, I had a Axe rossi mamba .21 nitro engine and he runs great but I am worried about the temp it goes upto 317F . but there's enough smoke, actually if you just see its still on the rich side. Once I want to richen it more to a lower temp 275F it boggs and sometimes off. And I check the plug enough fuel in it. Ussually all my other engine 3 LRP, 1 picco, 1 sh, and 1 xtm they only got 220F max. Any input guys? Thanks. By the way outside ambient temp is 38C here in Dubai.

 

[Rolex]

Centigrade? Your engine goes to 317 degrees CENTIGRADE?
That's 602 F. That doesn't happen.

 

[olds97_lss]

Barf: What the hell was that?

Lonestar: Spaceball 1.

Barf: They've gone to plaid!

That be HOT!

You sure your gauge is working right?

 

[avelciario]

Hi Rolex, Sorry sorry 317 degrees F . Am very sorry.

 

[olds97_lss]

Could be an air leak somewhere in the tank, lines or engine itself. Do you see any collection of oil/dirt on the engine anywhere?

Getting temps that high can be hard on things. If your richening it and it bogs, then that would suggest it's getting more air somewhere that it shouldn't be.

I get leery of temps above 275F even on an 80F day. I know you will read/find info stating that "you tune for smoke and sound, temps are not important", but once you get up near 300F, your burning the oil in the fuel vs letting it remain as lube and spit out the pipe. The only time I've seen temps that high was when something in the drivetrain was causing excess drag or an air leak was present via a bad seal or crack in the crankcase.

 

[avelciario]

That's why I just removed the engine from the rig, to fully check, only on the front bearing but that one before I run on lower temp, but after I lean it out no more leak on the front bearing. And the fuel tank is new. But I will try more to check for the leaks.

 

[avelciario]

I've just finished checking for air leaks with soap the only air leak I can see is in the rubber on the slider of the carb. And regarding the drag, I just find out my inner clutch bearing was bad. Thanks for the inputs. I will try again to run next week. If any ideas just let me know. On the slider of the carb there's no o-ring I just put a silicon gasket on both ends. any ideas how to fixed it? Cause I am sure I can't find it here in our place replacemnets for this engine.

 

[Extreme RC Mods]

How much fuel have you run through the engine?

 

[Rolex]

Often overlooked is a 10 second fix. It might be your LSN. If it's too lean, nothing you do with the HSN will bring your temp down.

 

[Extreme RC Mods]

A rich HSN will cool the engine while throttle is applied, but it should be dropping in temp slightly while idling.

 

[avelciario]

When its idling perfect once I give rev zero to half then leave the throttle he we let the idle hang first for 3seconds then drops to low rpm, and same once I run it full throttle after released the throttle hang for 3 seconds then drop the idle, supposed to be it should be a little bit longger. and all have smoke.

 

[Extreme RC Mods]

How much fuel has been run through it?

 

[avelciario]

How much fuel has been run through it?

almost 12ltrs, this is a new engine, and I just finished open all, check the piston and the pinch, and its all good, inside enough fuel coated on the parts, same as new the parts inside.

 

[Extreme RC Mods]

How big is your idle gap? I would set it to .5mm and re-tune, a big idle gap will often cause some of the problems your having. Also what fuel and % nitro/oil are you running and what plug?

 

[avelciario]

idle gap is less than 1mm already, I use RAPICON 25% nitro and 9%oil. Same fuel I used in alll my engine but they got no problem. That's why next friday I will try to tune it again for 1mm idle gap and try not to touch again so that I can richen up a more my LSN but as far as I remember the engine doesn't run well with a bigger gap and too very rich LSN just to lower the rpm on idling. But I will try again. It seems It's opposite on my case....hehehehe.

 

[avelciario]

Hello Guys, I just tried aain to run today. I make my idle gap to 1mm and back to factory setting all the needle the adjust the LSN 1/8 of a turn counter clockwise untill I got a good acceleration and after I adjust the HSN untill he got enough top end that suit in our tight race track. And good news later I check my temp for almost two tanks and I got only 245F. but my idle a little bit higher and enough smoke. Thanks for all the help. One thing I learn every engine has its own characteristics, picco engine tuning style does not apply to my Axe Rossi engine.

 

[Rolex]

They all have a "Happy Spot".
Sounds like you found it.

 

[avelciario]

Yes, finally I found it, and maybe resealing again the engine gives a big help. Thanks again for the help.