[Sloleaner]

I cleaned up this 50cc motor and got it started but after a minute or less the motor stops because the plug is fouled with crankcase oil and I have to drain the expansion chamber. Anybody know what causes this?

 

[StrokeitTwice443]

is it doing it just sitting there idling? if so, it sound like your pilot is too big, or your choke is on. does it leak gas from the carb vent line when it is sitting and not running?

either way, you are getting too much fuel for sure. if it's doin it under normal operations, then it could evn be that your needle is to high, or your main is too big.

 

[Sloleaner]

motor oil

It's not fouled with mixed fuel and 2 stroke oil, it's 30 wt crankcase oil that loads up the cylinder, smokes to beat the band and then comes out the exhaust pipe. Are my rings broken?

 

[stuntman88]

it is your crank seal on the oil side you have to replace it

 

[StrokeitTwice443]

wait, are you talking about a four stroke?

 

[2strokefan]

wait, are you talking about a four stroke?

What it sounds like to me??ope:

 

[Sloleaner]

No this a Yamaha YZ50, I keep saying crankcase oil cause I,m not that sharp, I'm trying to say is the oil you put in the oil fill plug that lubs... what the transmission and clutch and maybe the crank bearings?

 

[StrokeitTwice443]

that fluid will not foul your plug unless you have a leak between the gearbox and the crank case. does your exhaust smell bad, or different than the way it should with just mixed gas running through it?

 

[Sloleaner]

Seems like that crank seal makes sense to me except, would the motor run at all with a leak like that, It is very hard to get it started. Aw I think your right, I'm goin in...I think

 

[StrokeitTwice443]

Seems like that crank seal makes sense to me except, would the motor run at all with a leak like that, It is very hard to get it started. Aw I think your right, I'm goin in...I think

yes, it will run like that.

 

[Sloleaner]

Thanks you guys, allaya for giving it some thought, sorry I couldn't describe it better. Thank you Stuntman88 for nailing it so adeptly, gonna start it tomorrow. And I'm gonna find those Maico pics.

 

[2strokefan]

that fluid will not foul your plug unless you have a leak between the gearbox and the crank case. does your exhaust smell bad, or different than the way it should with just mixed gas running through it?

X2 on what Scott said.^^^^^