Scag Turf Tiger Kohler CH25S

[MHennel]

I have a Turf Tiger from 1999 with a Kohler CH25S engine. Unit has about 1900 Hrs. When cutting the grass the other day it started to run rough and stopped. When I tired to restart , it only backfired. I check the spark and was getting minimal spark on both cylinders. I replaced the plugs and the same thing, minimal spark. I replaced the coils a couple of years ago. This is a CH25S with the SAM module. SInce that is not available I purchased the replacement kit with the new flywheel and ignition coils. I get good spark on both cylinders now but when trying to start it tries to but just backfires. Looking at the plugs there is a little bit of soot on them. the backfire is from the air cleaner, not the exhaust. Any ideas what this could be? Could it be something simple or am i looking at replacing the engine.

 

[hlw49]

Check push rods or cam.

 

[MHennel]

I will check those over the weekend. I amalso going to verify the key didn't fall out when I put the flywheel back on.

 

[Tiger Small Engine]

I will check those over the weekend. I amalso going to verify the key didn't fall out when I put the flywheel back on.

1900 hours on a Kohler Command is about the life of the unit with regular maintenance. Your mileage may vary.

 

[hlw49]

Wow That isn't what the ones we have out there get I have seen them with over 8,000 hours on them and still going. I'd say 3,000 to 4,000 hour would be the average.

 

[MHennel]

Wow That isn't what the ones we have out there get I have seen them with over 8,000 hours on them and still going. I'd say 3,000 to 4,000 hour would be the average.

i think rather spend much time troubleshooting it, I am going to replace it. It shoudl be fairly easy so I am good for several years at least. The rest of the mower is in really good condition. It is one where everything is heavy guage metal, no plastic.

 

[bertsmobile1]

1900 hours on a Kohler Command is about the life of the unit with regular maintenance. Your mileage may vary.

the 19 Hp on the cub had done over 3000 hrs when the landlord got it.
did another 1500 before a screw came out of the butterfly ending up costing a pair of valves 5 years ago
The hour meter died shortly after that but it does 2 hours week every week cutting the 1/2 acre around the house and 14 hours a month trimming around the olives
We are currently doing new oil seals on one of the twins that went 15' under water
This one had 5000 hrs on the meter when the meter stopped working
It is replacing one with over 3000 on the meter when it was bought
That one was just going to get new rings but we found a crack in the liner when we honed it so that one is going to be a parts donner .
To be fair we have needed to replace the starters and one alternator but other than that nothing more than routine maintenance, annual oil change with new filters
Then there is the Dingos , Kangas , stump grinders & ditchers in my repair run
They all have astronomical hours on them
In fact some of the Kohlers are doing better than the Hondas which quite rightly was a surprise .
The customers with Kohler powered skid steers do seem to have a problem with alternators as gravel continually seems to get under the flywheel & messing up the stators & coils at a rate high enough to warrant one of the aftermarket suppliers getting flywheels made locally for them and a couple of other workshops doing exchange flywheels .

I would expect to get 1900 hrs from an Intek

 

[MHennel]

I verified that the flywheel is installed correctly and the key did not fall out during install. I also checked the compression in each cyclinder and I have right at 150 LBS in each. Any ideas what else could cause backfire when trying to start?

 

[MHennel]

Well I finally had a chance to get back to this. Per above suggestion I took the valve covers off to inspect the lifters. the first side looked fine and the moved easily. Whn I did the other side the problem was obvious. The rocker arm bolt had come loose and the rocker arm was no longer on the valve spring.put it back and torqued the nut down and the engine fired right up. It actually runs better now, so I am still glad a replaced the ignition coils and flyhweel from the SAM to MDI. Spent 2/12 hours cutting the grass no issues. Did break off one valve cover bolt that was a pain to get out, but I am good to go. Should have looked at this first, but everything pointed to an ignition problem

 

[Tiger Small Engine]

Well I finally had a chance to get back to this. Per above suggestion I took the valve covers off to inspect the lifters. the first side looked fine and the moved easily. Whn I did the other side the problem was obvious. The rocker arm bolt had come loose and the rocker arm was no longer on the valve spring.put it back and torqued the nut down and the engine fired right up. It actually runs better now, so I am still glad a replaced the ignition coils and flyhweel from the SAM to MDI. Spent 2/12 hours cutting the grass no issues. Did break off one valve cover bolt that was a pain to get out, but I am good to go. Should have looked at this first, but everything pointed to an ignition problem

Glad you found the issue. Sure some engines will go 5000 hours, just like some cars/trucks will go 425,000 miles. Total outlier time and mileage vs normal amount.
If the rocker arm stud backed out of cylinder head, it would be impossible to get a 150 psi compression reading, just saying.