can a worn backplate bushing cause lean conditions

[TypeONegative]

Hi i have quite a few revos (5) only ones brushless and many other electric/nitro rcs, but the one i been runnin in the snow has the old 2.5r in it, god only knows how old it is i can see mar marks all over inside the block from someone inexperienced changing out bearings, had an extra piston and sleave so put it in all was perfect till now, it will run perfect at 5 turns out at 25 degrees Fahrenheit but its on the lean side where its pulling wheelies, trouble is few minutes into a tank it gets hot and i tried turning out to 6 turns and it got leaner! Took engine apart cleaned and disassembled carb, had some dirt in it but i noticed the one way shaft in the backplate had a bit of play, i had a brand new one from an engine that got cracked and it had no play in it, could this have veen my problem? I set the hsn at 4 turns out assembled everything and will try it tomorrow, i have a few new 2.5s but i like to run them till the bearings go then i use em for parts and toss in the new engine, checked fuel lines and tank, in my many years doing this (started running nitro rcs by myself and tuning at 7) i never had this happen but only once a similar case, on a pro.15 t maxx i bent the hsn but it was a bit different than what I have here, thanks in advance and sorry for any improper grammer, trying to get better at it! Anyways hope everyone has a great day, burnt flowers fallen, TypeONegative

 

[Certified Mike]

I would look for an air leak causing your lean issue. Unless the play has somehow worn the sleeve out of round, I'm not seeing how it would effect it like that. I would also be looking at the carb and the needles/o-rings. The way you describe the lean condition as you're backing out the screw leads me to believe something else (in the carb) is the real issue. I'm curious to know what you find. Please post back!
Good luck!

 

[olds97_lss]

If there was a lot of play, it could cause your issue. The only thing keeping that sealed is oil from the fuel, but once there's slop in the input shaft, it will suck air in there all the time and make it run poorly.

 

[Certified Mike]

I think I agree. I read too quickly and thought you were saying that the bearing had already been replaced prior to the leaning with the carb adjust. An air leak anywhere in the case can Def cause your lean issues!

 

[TypeONegative]

I think I agree. I read too quickly and thought you were saying that the bearing had already been replaced prior to the leaning with the carb adjust. An air leak anywhere in the case can Def cause your lean issues!

Thanks! So i ended up running it anyways for anothet two quarts of bashing and it blew, it was the front seal new engine same carb workin great

 

[cbaker65]

Thanks! So i ended up running it anyways for anothet two quarts of bashing and it blew, it was the front seal new engine same carb workin great

Don't quite understand your wording! You say that the engine blew up ,or the bearing blew out?

 

[TypeONegative]

Don't quite understand your wording! You say that the engine blew up ,or the bearing blew out?

Couldnt tell what it was, ran the heck out of it and the piston shattered, when i pulled it apart the front seal had pieces missing, this engine had two p/s put in and one set of bearings and over 40 gallons, money well spent

I built an engine braak in stand, but it requires new shoes afterwords lol worked great was able to ball park turn it before putting it in the truck to.

 

[cbaker65]

Couldnt tell what it was, ran the heck out of it and the piston shattered, when i pulled it apart the front seal had pieces missing, this engine had two p/s put in and one set of bearings and over 40 gallons, money well spent

I built an engine braak in stand, but it requires new shoes afterwords lol worked great was able to ball park turn it before putting it in the truck to.

Ah ,ok!...nothing like giving an engine a proper last death run!....

 

[TypeONegative]

Ah ,ok!...nothing like giving an engine a proper last death run!....

Absolutely, when it flipped on its lid i held it w.o.t for around 20 seconds, then pop lol after all the use i got from it the block internally was beat and the crank, the ps was newer but got scored from running lean so said let it rip! New 2.5 running great

 

[Certified Mike]

Ah yeah... Well, now you've got more parts! When you roll, it's gonna likely lean out your engine anyways... The fuel is highly unlikely to flow properly. From the sound of it, you weren't looking to save it anymore anyways!

 

[cbaker65]

Ah yeah... Well, now you've got more parts! When you roll, it's gonna likely lean out your engine anyways... The fuel is highly unlikely to flow properly. From the sound of it, you weren't looking to save it anymore anyways!

I have the solution for that ,just do an airplane tank style with fuel tubing an fuel clunk ,it allows the
fuel filter to move up or down inside the tank!...

 

[Certified Mike]

I would never have thought of that as a solution. Of course, I have yet to get the urge to tach out anything after a roll either! Lol!