Now I have a problem

[Digger 258]

So after bringing my PT-425 (Kohler Command Pro 25) home and changing the engine oil (synthetic - 2 quarts), the fuel filter, the hydraulic filter, cleaning the air filter, as well as greasing all the zerks, I began using the PT to move some heavy stuff around the yard. I ran her for about 2 hours on and off with no problems - until I went to temporarily park it. I moved the throttle down to idle and it shut down instead of idle. Wouldn't start again. Smoke out of the exhaust when cranking. I immediately checked the engine oil, which showed me it was a bit over filled (it was just a hair above the full line when I changed it, even higher on the dipstick after running.) I checked the spark plugs - they are black, but not wet. I checked for spark - it's there. I checked if she was getting fuel by disconnecting the fuel line at the carb, and after a few cranks - fuel shot out. I tried starting fluid, nothing.

I cranked it with both plugs out, and I can feel compression with my thumb over the plug hole on both, though the passenger side had a touch of oil on my thumb. Nothing sounded bad when I was running her, the only other thing I noticed is the carb is wet when I look down inside. Could it be that I put synthetic in it after 650 hours of running I don't know what in there? Could I have overfilled it and broke something?

So my first day really using the PT has been frustrating. I drained some oil so it's reading in the middle of the dipstick fill level, and I'm gonna get new plugs tonight. Other than that, I have no clue what to do. Any ideas?

 

[Digger 258]

I just checked the compression with a gauge - 90 psi on the left, 85 psi on the right. so spark, fuel and compression . . . maybe the carb is not working right.

 

[woodlandfarms]

Carb is my guess. Either something got into it or it is gummed up.

quick question, what kind of fuel are you using? Recommend you finding a local source for non ethanol if you can.

Carbs aren't very scary, just a PITA. not sure what kind of carb you have but maybe this will help.

https://www.youtube.com/watch?v=s7Mxp1X7BnU

 

[woodlandfarms]

Let me ad I am pretty sure you didn't break anything. Pretty common issue you are working on. You did a good job of doing an initial diagnosis. There can be other culprits but given what you have said, this is a good jumping off point (the carb).

 

[Digger 258]

I just ran 7 octane local gas station gas in her. Thanks for the link - I'll investigate the carb tonight. I think the machine sat for a long time before I brought it home, but not sure.

 

[Rustyiron]

Some type of safety switch?? Seat, pto,etc. Maybe low oil alert not working? I would think that this would not be the problem because you say you have spark. Dry plug and an engine that has sat, I'd say Woodland farms is on track with the carb.

 

[woodlandfarms]

Yeah, new gas (with ethanol) is bad for small engines, especially if they sit for more than 3 months. It tends to varnish up really quickly. You said you did the filter, while it is not your issue one day you will want to clean the strainer in the gas tank.

Carb is no big deal, don't be intimidated. Clean work area is essential, lots of light, and plenty of clean bins to keep parts in.

 

[Rustyferrious]

Sometimes the float get stuck in the carb due to varnish buid-up. Happened on my mercurser 3.0 IO last spring. Try tapping on the side of the housing with a small plastic mallet to see if you can free it up. Don't use anything metal like a hammer - you may damage the housing.

 

[Digger 258]

I'm thinking you guys are right - it's something with the carb, since when I sprayed starter fluid in the carb, nothing got into the cylinder, where I am sure I have spark and compression. I pulled the plate off that holds the air cleaner to the carb, and it's packed with oil caked dirt. It looks a little complex and intimidating, but tomorrow I'll try first tapping on the float bowl, which I assume is on the bottom somewhere, and if no luck there, I'll try to figure out how to get that carb off and on to a clean workbench. I sure hope that it's a simple issue - I am itching to get back to using the machine! In the meantime, work gets in the way of my grand plans for the PT. . . Wont be able to do anything until tomorrow night. Wish I broke down in a more convenient spot! Thanks agan.

 

[MossRoad]

There's a rubber breather tube, about 3/8 ID, that sticks up through the Air Cleaner Base (part H on page 21 of that service manual I linked to) on my Kohler. It comes up through the base and sits right over the throat of the carb. If I move it away from the carb throat, the tractor dies and if I move it to close to the carb the tractor spews smoke. It part E on page 79.

Also, look on page 25 for troubleshooting carb issues.

There's some good stuff on page 32 for spark plug conditions.