Predator smoking on start-up

[Minibike Mogul]

Hi everyone! My predator 212cc engine has been smoking (white) on start-up since the last few days. (It goes away when i turn the choke off). I was wondering if this was dangerous or just what is going on with the engine. Other than that it runs just fine. Thanks in advance!:laugh:

 

[noseoil]

How old is the motor & how many hours. White smoke is oil burning inside the combustion chamber. It could be rings, did you overfill crankcase with oil, could be seep from the valve guides (did it fall over recently on its side for a while?), etc. Is it a lot of smoke or a little?

 

[Minibike Mogul]

How old is the motor & how many hours. White smoke is oil burning inside the combustion chamber. It could be rings, did you overfill crankcase with oil, could be seep from the valve guides (did it fall over recently on its side for a while?), etc. Is it a lot of smoke or a little?

The engine is about 4 months old and i have probably run it for less than 20 hours. I am guessing it would be rings maybe?, but as i was saying the smoke goes away when i turn the choke off (when the engine gets hot). On start-up, there is quite a lot of smoke.

 

[SAS289]

Has the amount of smoke on startup stayed the same over multiple cold starts or has it changed in any way?

If this was a car engine I would be concerned that one or more valve seals are going bad. When the car is shut off hot oil could seep down into the combustion chamber ready to be burned up on the next cold startup.

You may think about disconnecting the crankcase breather from the airbox (if you are still connected) to see if the symptom still occurs. Run the engine then disconnect the hose. Then see if you get smoke on the next cold start.

I don't think piston rings would cause smoke only on startup. You should also try to remember if you made any changes just prior to when this was first noticed.

 

[creia]

Pull the spark plug and take a look at the color and if there are any deposits (e.g., oil, carbon, etc.) on it, which will give you some direction on what is going on.
Michael

 

[Minibike Mogul]

Has the amount of smoke on startup stayed the same over multiple cold starts or has it changed in any way?

If this was a car engine I would be concerned that one or more valve seals are going bad. When the car is shut off hot oil could seep down into the combustion chamber ready to be burned up on the next cold startup.

You may think about disconnecting the crankcase breather from the airbox (if you are still connected) to see if the symptom still occurs. Run the engine then disconnect the hose. Then see if you get smoke on the next cold start.

I don't think piston rings would cause smoke only on startup. You should also try to remember if you made any changes just prior to when this was first noticed.

Do you think this could be a warped exhaust valve? I have been running a very short header (2 inch) while waiting to get a new one.
I will also try disconnecting the breather tube.
Thanks a lot!:thumbsup:

 

[SAS289]

Not sure on the valve itself.

The breather tube idea is just a troubleshooting thing in an attempt to eliminate one possibility.

What would you observe if you got the engine hot, shut it down, then choke and start? Smoke or not?

You said the smoke stops when the choke is opened. Does the smoke continue if you leave the choke closed for a longer amount of time than normal? Most people open the choke just after startup.

 

[Minibike Mogul]

I checked the spark plug after letting the engine sit overnight and there definitely was some oil residue on it.

I will try turning the choke back on once the engine is hot to see if the smoke comes back.

Again, thanks a lot for the help!

 

[deezildennis]

Probably just running fat when the choke is on. Slide choke to the off position once engine is running.

 

[DeadPixel]

Maybe try to start motor and shut it back off before the symptom clears up and then pull the plug. That way you can see if it is oil or fuel. Like SAS298 said, this is usually a symptom of a bad valve stem seal on a car but on these motors I know most people don't use seals. Could be a worn valve guide. Have you lost power? Try starting motor with out the air filter and see if it still dose this.