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.

 

[SpringHollow]

if the engine was used with non-ethanol gas and now with ethanol, it would not be unusual for a load of crap to get dislodged and plug up things. I hate ethanol gas.

Ken

 

[Kent]

I think the problem is flooding.

I have the fuel injected 28 hp Subaru Robin in my PT425 and have been having the problem lately of what I think is a weakening fuel pressure regulator that is built into the FI throttle body. As far as I can tell there are no schematics, rebuild instructions, or replaceable parts for the throttle body. On hot restarts half the time the engine floods and won't restart. So I have learned to "simply" shut off the fuel petcock I had installed under the gas tank, crank a few times, and it starts right up. Open the petcock after the engine catches, and I am good to go.

I used to think it wise to turn the key and pause for a second to let the fuel pump get up to pressure at the throttle body on cold starts, and that worked for many months, but now all that does is flood the engine. There is just too much gas in the cylinders at startup, both cold and hot.

So rather than turning the petcock every time the engine floods I am contemplating mounting a switch on the dash to control the power to the fuel pump, turning it off until flooding is cleared.

The non-FI Robin has a the vacuum powered fuel pump. I am thinking a normally open solenoid valve inserted into the "pulse pipe" between the fuel pump and then engine would do it. Search EBay for "1/4 inch NORMALLY OPEN 12V DC Solenoid Valve" for samples. Also install a 12v switch to control the solenoid.

 

[MossRoad]

I know my Kohler floods easily, especially if the air filter gets dirty. It happens on hot starts if I shut off the machine for 10-20 minutes after long usage. When I try to start it, it floods. I know the air filter is dirty, so I clean it, then crank it with the throttle all the way off until it starts to sputter, then increase the throttle until it starts.

 

[Digger 258]

I thought it might be flooding at first, so I took off the air cleaner and cranked it a bit. after about 20 minutes of trying different throttle/choke arrangements, I went into panic mode and started checking the fuel pump, spark and compression. I hope when I get home tonight I crank it over and it just fires right up . . .that would be nice. But I suspect there's a problem with the carb. I'll post what I find out.

 

[cqaigy2]

If it's flooding, the spark plug will most likely be wet. While you have the spark plug out, double check for spark.

 

[Digger 258]

when I hold the spark plug against the head bolt and crank, I get a big fat spark. I have fuel spitting out of the fuel line downstream of the pump. I have 85-90 lbs of compression. I figured it's gotta be the carb. When I got home, I charged the battery, checked for spark again, and sprayed some carb cleaner right into the cylinder through the plug hole - then put the plug back in and tried to crank. Nothing.

So I started taking the carb off. When I got the carb off, I noticed a bit of fluid in the intake manifold. The carb was filthy on the outside. Took it to a clean bench with lots of tupperware containers . . .

 

[Digger 258]

The carb was so dirty on the outside, I was convinced something was sticking in there. I took off the accel pump on the bottom and separated the main carb body to get to the floats. It appears immaculate in there! I am completely stumped. I guess I should clean out the carb really good with fluid and air, and put it back together to see what happens. I'm not sure what the electrical component is on the carb that I had to unplug, or if it has any bearing on my problem. Haven't searched the engine manual yet though. (and because Murphy rules, I "temporarily parked" the PT in front of other vehicles I need to move!) It's gotta be either something tragic, or something simple . . .

 

[MossRoad]

That electric component may be your fuel shutoff solenoid.

 

[woodlandfarms]

The thing about a carb is that all it takes is something small... Really small. I would do the teardown just for good measure. And yes, you will soon learn that the only time the PT lets you down is when you desperatly need it or it is completely inconveniant to repair (Actually I think this is a rule for any tractor - Never had one break down in the shop, it was usually fully loaded in the back 40 in the middle of a muddy field).

 

[ponytug]

And snowing...with grizzly bears nosing around.
:laughing:

But yes, I once blew a wheel motor seal on a 35 degree angle, down the hill from the road. Not exactly the place that you would choose to try and do open heart surgery to replace the wheel motor.

But back to the OP questions:
I'd be checking that fuel solenoid to make sure it is functional and not sticking on you.

X2 on Woodlandfarms comments about how small a particle you need to gum up a carburetor jet. It can be really, really tiny, which means when you do the tear down and rebuild, the area has to be really, really clean and free of dust, including cleaning the fuel lines and solenoid so that you don't wash more crud into your nice clean carburetor.

All the best,

Peter


All the best,

Peter

The thing about a carb is that all it takes is something small... Really small. I would do the teardown just for good measure. And yes, you will soon learn that the only time the PT lets you down is when you desperatly need it or it is completely inconveniant to repair (Actually I think this is a rule for any tractor - Never had one break down in the shop, it was usually fully loaded in the back 40 in the middle of a muddy field).