"Thermal Runaway?!?!?" Revving on Muffs

[ShellBack101]

Question I read in a post her by JTEXAS saying not to rev an engine on the muffs as it will create "thermal Runaway" and damage your engine. Well last night I was trying to adjust my carbs and keep the engine running and you Guessed it....revved the engine on the muffs. Have I ruined my engine? I did have trouble starting it after it quit, can anyone elaborate on Thermal Runaway, and what exactly happens if you rev it up on the muffs? ( I did not have it in gear.)

 

[Gary H NC]

Re: "Thermal Runaway?!?!?" Revving on Muffs

You are ok, Runaway is when the motor revs itself up very high and turning the key off does not shut it down.You would know if that happens!

 

[F_R]

Re: "Thermal Runaway?!?!?" Revving on Muffs

I've never crawled up inside a motor that was doing it to see what is gong on, but it is a memorable event isn't it?

Actually I don't think it is the result of the same cause in every kind of motor, and "thermal" probably isn't an accurate term in many cases. The old Big Twins did it all the time and killing the ignition would stop it, so they weren't actually in thermal mode. Just flywheel action and high vacuum. The throttle plates don't shut completely closed on a two stroke, or it couldn't run.

My understanding of thermal runaway would be like a model airplane engine that runs without spark once you get it going with a glow plug. The fuel ignites just from compression and heat. So do Deisels.

Wish I understood everything I know.

 

[Theoutdoorsman]

Re: "Thermal Runaway?!?!?" Revving on Muffs

Tashasdaddy's reply to another individual, concerning this matter, summed things up pretty good. Here's a link to a clasis runaway condition............

http://forums.iboats.com/showthread.php?t=194958

If it ever happens, you'll no doubt know it happened.

 

[ShellBack101]

Re: "Thermal Runaway?!?!?" Revving on Muffs

Thanks Guys I can sleep tonight. Now I jsut have to get this thing running....