PT425 ran great yesterday, won't start today and backfiring through the carb

[NC1]

Quick update-

She is running as good as new for now! I ended up replacing the spark plugs and she cranked right up and runs great.
She will run on one cylinder, so I am a little stumped as to what caused it. The right side plug was very fouled, did not get a chance to see the left side plug, as I was taking it out, it slipped out of the socked and got wedged between the head and heat shield, spent 30 minutes trying to get it out, heat shield would have to come off and since its not hurting anything, its going to stay there until I have a reason to take the shield off.

Thanks for all of the advice. I'll put her through her paces and keep you posted.

 

[ponytug]

@NC1 Congratulations on getting it running. If only one of the two plugs was fouled badly, I would suspect that valve clearance was off or intermittent electrical contact on the wiring. As you know, spark plug wires do degrade with time, as do the boots.

Personally, I would replace both wires and plugs just because you have had trouble. When you get a moment and have valve cover gaskets, I would also take a peek at the valves and clearances.

I realize that it is a pain, but I wouldn't leave the plug in the heatshield, if it were me. Parts have a way of migrating to inopportune locations, at least in my experience.

All the best,

Peter

 

[MossRoad]

If I'm not mistaken ( that's a 50/50 ) I don't think the spark plug wires are removable from the coil-end, only the spark plug end. At least, that's the way it is on the Kohler. Kinda weird if you ask me.

 

[ponytug]

If I'm not mistaken ( that's a 50/50 ) I don't think the spark plug wires are removable from the coil-end, only the spark plug end. At least, that's the way it is on the Kohler. Kinda weird if you ask me.

As I have zero experience with the Kohler engine, I am sure that you are right. A bad coil would also explain a fouled plug. I forgot that some of the Kohlers have coils on each spark plug lead.

All the best,

Peter

 

[TwinOaks9]

I have a 2018 PT 425, with a Robbins, in the 3 years I have chased all the symptoms above and on the attached link, it wasn't till I replaced the coils, did my problems go away. Now she runs like a top and even starts in cold weather.

 

[agjones]

I have a 2018 PT 425, with a Robbins, in the 3 years I have chased all the symptoms above and on the attached link, it wasn't till I replaced the coils, did my problems go away. Now she runs like a top and even starts in cold weather.

Same except then mine blew and I replaced it with a Kubota. Runs like a top, even in cold weather. Haven't stalled it in several years...not even sure I can.

 

[Lnk]

I have a 2018 PT 425, with a Robbins, in the 3 years I have chased all the symptoms above and on the attached link, it wasn't till I replaced the coils, did my problems go away. Now she runs like a top and even starts in cold weather.

Can you tell us what the part number of the coils, price, and where you got them. I would love to have mine start easier in colder weather.

 

[TwinOaks9]

I had a local tractor shop do the work as I don't have the equipment or the tools to pull a motor, the work order says the part number is 263-78203-01 and they were $270.00 each. The work was done is July so the prices are probably out of date. I also installed an electric fuel pump last year and that really seems to help with the cold start as well. If it is really cold I use a block heater on the hydro oil tank and a Energizer Multi Function jump starter to give the battery some extra kick.