Grinder backfires

[kotierratree]

When I start stump grinder it runs fine. When i engage cutter wheel and start grinding a stump it pops, backfires, and loses power. Any suggestions as to what would cause this?

 

[MOE]

Sounds like timing or bad coil. What kind of engine is it?

 

[Walt41]

Start with a fresh set of plugs, inspect the wiring for chaffing and if that does not cure it, wait till dark and fire it up while misting the ignition system with water from a plant sprayer, sometimes you get micro cracks in wires or distributor cap that are not obvious. From there a new set of points and condenser (if applicable)
Could also be a fuel issue, pull the bowl drain and see if it is flowing clean, check fuel filter as well, might try running it on straight sea foam for a few minutes if you are not comfortable with tearing into the carb.

If it is a smaller engine, check the flywheel keyway first!

 

[OLD MAN GRINDER]

Sounds like a fuel problem,,,probably dirty fuel filter....

Bob....

 

[kotierratree]

Sounds like timing or bad coil. What kind of engine is it?

it is a kohler 25HP ch730-0019

 

[Plyscamp]

It is possibly a lean fuel mixture causing the problem. The Kohlers are famous for the intake gaskets failing between the cylinder and intake manifold.

 

[ropensaddle]

Does it have auto sweep ?

 

[Walt41]

Is that the one with the odd looking fuel pump on top? I fixed a hydroseeder with a 25hp Kohler on it a while back and that that thing made me cuss like the father from "A Christmas Story" finally traced the issue to a corroded terminal that fed power to the fuel pump, if you have the same setup try to power the pump direct, another area of frustration is the oil level sensor, sometimes they go bad and don't quite kill the ignition but rather disrupt it...causing backfires and low power as they try to shut down the motor due to a perceived lack of oil.

 

[sticknstring]

It is possibly a lean fuel mixture causing the problem. The Kohlers are famous for the intake gaskets failing between the cylinder and intake manifold.

This is the most likely answer. I had a 252 with a Kohler that did the exact same thing. It would pop and backfire under WOT. I fought it for months and threw lots of parts at it in frustration. Ended up being a bad intake gasket on the front cylinder.

 

[NCgrinder]

Backfire

I'd bet my money on a blown intake manifold gasket.. I replaced a lot of them on my 252,so much so I'd buy them in packs of 10!!
I finally found a sheet of "dead-soft" .030" copper and cut them out of that. Also leave as much material as possible around the outside perimeter..The trick also is the torque the bolts evenly and with an inch/pound (or N/Meter) torque wrench..I think I've only changed them once since I did that
Kohler Command 25's are famous for that
Stan