Spark Plug Specs for PT 425 w/ Robin EH72

[toolz_not_toyz]

From the Kohler FAQ I quoteth...

Q: Why does my engine backfire when I shut it off?
A: Your owner’s manual has proper shutdown procedures to avoid this occurrence. If your engine is equipped with a fuel shut-off solenoid, be certain to set the throttle between half and full throttle before turning the key switch "off."

These engines operate on vaccuum. There's no fuel pump. As Duane pointed out, the solenoid simply cuts off fuel to the jets.

The full FAQ can be found here:

Kohler Service FAQ

 

[Bird]

David, before fuel shut-off solenoids, I idled engines before shutting them down and only rarely had a "pop" and not a very loud one, either. But with this 14 hp Briggs in my Toro, I would literally be afraid of blowing the muffler off of it, or splitting the muffler. So I guess it depends on the magnitude of the "pop." /forums/images/graemlins/tongue.gif

 

[Barryh]

<font color="red"> </font> >> I guess I missed the point of why this is bad. What did folks do before fuel cutoff solenoids? Just asking... <<

Once had an older John Deere that would back fire at shut down. One day while shutting it down next to a pile of leaves, it back fired and shot a flame out setting the leaves on fire.

Didn't know I could move that quick running for the hose. I'm sure the neighbors got a laugh out of it. Not to say that the PT would have that problem. /forums/images/graemlins/ooo.gif But always something to think about.

 

[Phils]

Actually, MR, I had just accepted the "PTPop" until this thread began. I understand better what causes it now as I agree with the hot exhaust pipe theory. It's not a huge bang and I can live with it. I've got the timing down too and maybe will ask my wife to "pull my finger" just after shutting the machine down!

On another note: s'posed to be great weather this weekend and the truck was here an hour ago dropping off my grapple bucket and box bucket. Yay!

Phil