My name is Mark and I am new to this site and have been in lawn care for 25 years. I am struggling with 2018 Scag Turf Tiger 52 in with a kohler 26 hp efi bogging down in all sorts of grass conditions. Also I have 2 Tiger Cat 2s that were new last year and one has the hurricane mulching kit that worked really well last year but this year bogs down even sitting on the trailer (joke). Any suggestions on how to alleviate these problems? One of the suggestions was to raise rear portion of deck 1/4 inch?? Any help would be greatly appreciated. The 2 tiger cats have 26 hp kaw efi's.
Lawnprolincoln
Same with dull blades, first thing I would've checked if that mower had came to me for repairs.
It's been doing this with two engines evidently so I would almost have to rule out an engine issue. The original engine was replaced at 675 hours? What happened to it?
Is the engine light on? If not then it's probably running on both cylinders. If it were only running on one cylinder the O2 would get fooled into thinking it was running lean do to the cylinder that isn't running would basically be an air pump. The O2 sensor would read that as lean and have the ECU add more fuel and that should trigger a lean code.
One thing to remember when checking RPMs. Let's just say this engine is set to run at 3600 RPMs. Depending on your tach it might only read 1800. With most engines tachs are designed to ignore one spark because most engines fire at TDC every time. That gives you a wasted spark on the exhaust stroke. With this EFI there is no wasted spark and the ignition modules only fire at TDC on the compression stroke so don't be surprised if you are only seeing around 1800 RPMs.
This is something that may be hard to do on some units but I've actually tied a string or wire to the governor arm and taken the unit out and mowed heavy grass. When the engine bogs down I pull on the string to see if there is anymore throttle left. If the governor is working correctly I shouldn't be able to get anymore throttle out of it. It should be wide open. If I can speed up the engine then I start looking at governor adjustment. Someone with the EFI diagnostic program and hook up to your engine and see how long your engine is running at specific RPMs and throttle position. If it bogs down often, the program should show that the engine has spent a lot of time a high percentage of throttle open.
Like I mentioned though if it's done the same thing with two different engines it's probably not an engine issue. I don't recall which manufacture it was but a few years ago someone put on the wrong diameter pulley or clutch I don't remember which but that was causing power issues. If affected a pretty significant number of units.
Is the engine light on? If not then it's probably running on both cylinders. If it were only running on one cylinder the O2 would get fooled into thinking it was running lean do to the cylinder that isn't running would basically be an air pump. The O2 sensor would read that as lean and have the ECU add more fuel and that should trigger a lean code.
One thing to remember when checking RPMs. Let's just say this engine is set to run at 3600 RPMs. Depending on your tach it might only read 1800. With most engines tachs are designed to ignore one spark because most engines fire at TDC every time. That gives you a wasted spark on the exhaust stroke. With this EFI there is no wasted spark and the ignition modules only fire at TDC on the compression stroke so don't be surprised if you are only seeing around 1800 RPMs.
This is something that may be hard to do on some units but I've actually tied a string or wire to the governor arm and taken the unit out and mowed heavy grass. When the engine bogs down I pull on the string to see if there is anymore throttle left. If the governor is working correctly I shouldn't be able to get anymore throttle out of it. It should be wide open. If I can speed up the engine then I start looking at governor adjustment. Someone with the EFI diagnostic program and hook up to your engine and see how long your engine is running at specific RPMs and throttle position. If it bogs down often, the program should show that the engine has spent a lot of time a high percentage of throttle open.
Like I mentioned though if it's done the same thing with two different engines it's probably not an engine issue. I don't recall which manufacture it was but a few years ago someone put on the wrong diameter pulley or clutch I don't remember which but that was causing power issues. If affected a pretty significant number of units.
2 machines with similar symptoms makes me wonder if maybe bad gas. Or maybe someone is messing with you and sabotaging your equipment.
Looking at Turf Tiger first, have you changed the fuel filter under the engine? another thing to look for is the fuel cutoff valve coming out of the tank gets plugged with grass and other debris very easily. Shine a light in the tank and if see if it has junk in it.
Now Tiger Cat does the problem do it on both tanks? Change to OEM Fuel filters that are rated at !0 microns not cheaper after market if you haven't already. What are the fuel pressures Should be 39psi on both engines. Be aware that the electric pump also has a non-serviceable filter in them that might also be plugged.
Are either of them throwing codes when they start acting up?
Now Tiger Cat does the problem do it on both tanks? Change to OEM Fuel filters that are rated at !0 microns not cheaper after market if you haven't already. What are the fuel pressures Should be 39psi on both engines. Be aware that the electric pump also has a non-serviceable filter in them that might also be plugged.
Are either of them throwing codes when they start acting up?
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