Unexplained Thing

[andyfen]

Guys. Something unbelievable happen to me. I was flushing my 720cc Engine, and the engine start increasing the RPM by self until (+- 5000RPM).

I removed the Digital Key and still running.
I shut down the DC Main Power and still running.
I was so scare that I start hitting with a wood stick the Spark Plug's Cable and finally I remove the Spark Plug's Cables (both) and the "stupid" engine still running.
Then I put the maximum throttle and the engine shut down.

I can understand everything, but, Engine Running without Spark Plug Cables!!!!!!!!!!
Does any body has an idea what happen? I don't want to have that experience again on the water.
:cuss:

 

[Coastiejoe]

It basically turned into a Diesel. Compression was high enough to combust the fuel. Normally. Pulling the choke out will kill a run-away 2-stroke.

 

[Ankeneyou]

It also means you have an air leak somewhere. Carbs, fuel selector, crank seals, etc.

 

[XP 787]

Air leak. As stated above pull the choke to shutdown.

 

[andyfen]

Oooooo that Right I never figure out like that, because Diesel it just need fuel and good compression.....Thank a lot..

I will put an Fuel Valve near to the carb to cut the fuel just for emergency...:thumbsup:

 

[andyfen]

Thank...:thumbsup:

 

[andyfen]

I check that but I will check again.:agree:

 

[BoLongo]

I had a runaway on the trailer about three weeks ago. Mechanically the engine survived but the hi-revs took out my rectifier that ended up taking out my MPEM. I pressure tested the engine after the run away and it held air. The air leak must have come for the carburetor base gaskets. From here on out I will only use OEM carburetor base gaskets about $10.00 each. Expensive, but the engine runaway will end up costing me over $1,500.