Is my motor bad?

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, and others.
I

Ides28

Well-Known Member
Messages
104
Reaction score
41
Hi, longtime lurker. can't get my king motors baja to start. i used it a few months ago and it seemed fine. i did a lot of drifting around a baseball field near the field where i run my rc's and it's really sandy and dusty. went to start it yesterday and couldn't. i tried resetting the carb to factory, a new spark plug, it has spark, the fuel line wasn't clogged, i tried with the choke on and it off, i tried giving it some throttle when pulling, i tried the oil in the cylinder test twice, i tried putting gas in the cylinder twice, i took the air filter off, tried leaning it half a turn from factory, richening it half a turn from factory, made sure the kill switch was working ok, reset the gap for the coil (it was ok), and i took the carb off and cleaned it with carb and choke cleaner and lots of compressed air. now, when i took off the air filter i noticed a whole lot of dirt on the velocity stack, which means a lot of dirt made it into my motor and ruined it? anyway, please have a look and see if you guys think it's ok. there are no major scratches but the plating appears to be worn off in a tiger stripe pattern but still feels smooth. can the plating be gone and the motor still work ok? is it ok for the top of the piston the be discolored like that?20201008_212631.webp20201008_213057.webp20201008_213407.webp
 

Attachments

  • 20201008_214031.webp
    20201008_214031.webp
    38 KB · Views: 7
  • 20201008_214048.webp
    20201008_214048.webp
    39.1 KB · Views: 11
  • 20201008_214128.webp
    20201008_214128.webp
    37.1 KB · Views: 11
Ides28 said:
Hi, longtime lurker. can't get my king motors baja to start. i used it a few months ago and it seemed fine. i did a lot of drifting around a baseball field near the field where i run my rc's and it's really sandy and dusty. went to start it yesterday and couldn't. i tried resetting the carb to factory, a new spark plug, it has spark, the fuel line wasn't clogged, i tried with the choke on and it off, i tried giving it some throttle when pulling, i tried the oil in the cylinder test twice, i tried putting gas in the cylinder twice, i took the air filter off, tried leaning it half a turn from factory, richening it half a turn from factory, made sure the kill switch was working ok, reset the gap for the coil (it was ok), and i took the carb off and cleaned it with carb and choke cleaner and lots of compressed air. now, when i took off the air filter i noticed a whole lot of dirt on the velocity stack, which means a lot of dirt made it into my motor and ruined it? anyway, please have a look and see if you guys think it's ok. there are no major scratches but the plating appears to be worn off in a tiger stripe pattern but still feels smooth. can the plating be gone and the motor still work ok? is it ok for the top of the piston the be discolored like that?View attachment 64532View attachment 64531View attachment 64536
Click to expand...
I doubt the ring is sealing with all those markings and stuff in the cyl, but I'd try a new ring and see if it will go, cuz if you tried everything ( which it seems you have) I'd think it's compression.
 
Either way you need a new air filter . I ran mind in very dusty conditions a few times and no issues. Worst comes to worst you need a new top end , they are cheap as chips for those motors. Or a zenoah longblock.
Ides28 said:
that's what i thought too but the oil test didn't work
Click to expand...
I don't think oil would have helped. Maybe for a compression test, but for actually running I don't think it will seal long enough. Correct me if im wrong someone.
 
yeah, after this happened i'm going to buy a genuine hpi one. i was told that if compression was the problem you put some oil in the cylinder and it would run for a few seconds or something and that's how you know if you have no compression
 
Ides28 said:
yeah, after this happened i'm going to buy a genuine hpi one. i was told that if compression was the problem you put some oil in the cylinder and it would run for a few seconds or something and that's how you know if you have no compression
Click to expand...
Pretty sure no manufacturer truly has their own "line" of gas engines but id get a zenoha based engine for budget sake
 
there was a lot of dirt in the velocity stack, that means my engine has had a lot of dust through it and it's shot? i'm a little newb about these motors. when i pulled the pull start it did give resistance, like a good amount, like my arm is strained from doing it so much. thanks for the help
 
yeah i'm probably going to do exactly that. i'm just scared that it's something else and i will have wasted all my time and money
 
Ides28 said:
there was a lot of dirt in the velocity stack, that means my engine has had a lot of dust through it and it's shot? i'm a little newb about these motors. when i pulled the pull start it did give resistance, like a good amount, like my arm is strained from doing it so much. thanks for the help
Click to expand...
I've gotten blisters in between my fingers from yanking the cord before... whats the engine type you have and @dougstar is correct head kit is the easy way out
 
You can get a top end rebuild kit for that engine for £22 in the UK, so probably about $28 in the states. They come with piston, ring, e clips for gudgeon pin, head, gaskets and spark plug.
They are a good kit and its a simple change over. I did it with my KM engine 3 times before I broke it properly.
I suspect all you've done by putting oil in the head is made the dust into a grinding paste hence those marks.
Its worth trying a rebuild, if nothing else its experience.
Also try removing fuel cap, you said you ran in lots of dust, maybe the breather is clogged, clean the carb out too.
Here you go.

https://www.kingmotorrc.com/product-kmkg290-01
 
Last edited:
You need to check out the bottom end as well, of it ate that much grit then the bearings got it in them as well. See how it turns over without the top end on it. Should be silky smooth, no discernable play. Looks like it was pig rich as well.
 
so can a motor have a loss of plating like that and still run ok? what else could it not starting be?
 
pull the plug , stick your finger or thumb in the hole pull the cord if it does not push out you do not have compression , replace the top end
 
Back
Top