Sorry for the long post, but I wanted to be as thorough as possible. (Summary of work at bottom if you want to skip.)
I'm at a loss and could use a little help here; I have a nice CC I bought back in 2015 and it ran like a champ. It has electric PTO (the wife insisted) and the Kohler KT735 24hp v-twin motor in it.
Fast forward just a little bit to right about this time in 2017; we had a tornado (microburst?) absolutely pummel my house and property ($140k worth of damage) which included ripping the carport I used to park my little riding mower under into shreds and flinging the resulting shrapnel for hundreds of yards. The mower appeared to have superficial damage (the entire hood assembly was ripped off and flung to who knows where and the seat was ripped up.) I put the key in and to my surprise it started right up! Unfortunately shortly after we got it going, the hydrostatic transmission died in it (it was still within warranty) so that had to be replaced at the shop.
However during the ensuing short drive once we got it back, the leads to the LED headlights were ripped from the frame and shorted out, resulting in a blown fuse. In my panic, I put in too large of a fuse and proceeded to melt the entire main harness. (Yep, that was my dumb move of the century.) I parked it in my barn and forgot it about it for several months.
Last year the grass finally grew too high and we got a notice from the city (that we don't live in, so I told them to stick it where the sun doesn't shine) and realized it was probably time to fix it. My Kubota tractor can mow for sure, but is really difficult to mow around the house with the 5' finish mower on the back. I bought a new wiring harness and replaced it, along with a new battery. Drained the gas, cleaned the carburetor and replaced the spark plugs, fuel filter and air filter. Changed the oil and filter. Bought an entire new hood assembly and replaced it. To my delight, it fired up (but not without assistance from some starting fluid.) Once it started running, it would surge, and turning on the PTO just dragged it down really bad. I checked the spindles and most of them felt like they were in bad shape so I replaced all of those, along with the belt. PTO engagement improved but still surges. It seems to idle fine hot or cold, but once you engage PTO it can't handle much grass at all. It just bogs down. With PTO off and just riding around, it seems fine.
I've since taken the carburetor off at least two more times to clean it - it doesn't appear dirty at all. Note that I'm extremely thorough at cleaning carburetors; I have an ultrasonic cleaner I sit it in for at least 30 minutes (the first run got a LOT of crud out) as well as some extremely fine needles used for cleaning 3D printer nozzles to clean the little jets in the throttle bore. The fuel cutoff/backfire preventer solenoid works as it should and the float/needle all appear in great condition. I've removed the center jet and all the little orifices are completely clean, I've also hosed it down and blasted all the little orifices with carb cleaner to ensure they're not blocked.
I did notice some oil leaking from one of the valve covers, so I took both of them off and used that opportunity to check valve lash - to my surprise three of the valves were fairly well out of clearance; anywhere from .010" to .015" which is far outside the .003" to .005" specs. Got the feeler gauges out and reset all of them to within spec and now it cranks a LOT easier and seems to have improved power a little, but still surging and still doesn't start right off the bat like when it was new.
One other area I had touched was the gas tank itself; it originally came with a strange little filter that was built-in to the tank itself, if you took the hose off the tank it was part of the nipple the hose attached to but was easily removed. This appeared to be a restriction and I noticed that crud would accumulate around the hole leading to the nipple which seemed to starve the motor a bit. I have since removed that tiny filter and upgraded to a larger fuel filter that would catch anything coming through, as well as lightly drill out the hole so that smaller particles could pass and be caught by the filter. Seems to be working well in that respect. The little nipple that passes up through the air cleaner assembly and vacuums vapors from the gas tank broke off during the storm, so I 3D printed a new one and replaced that with no affect either.
I also looked up how to adjust the governor (the external part anyhow) and did that. Didn't seem to affect anything at all. I've moved the spring up and down the different points to little effect, too.
As an additional troubleshooting measure I've ordered a new fuel pump and will replace the fuel lines just to be sure, but outside of that I'm at a loss. One other thing I haven't tried yet is to look for a vacuum leak so I'll give that a shot as well. Everything points to it running lean.
Unfortunately the hour meter was shattered during the storm too, and while I've replaced it I have no idea how many actual hours were on it.
Again, it runs great in idle with only a little surging, but lacks the power it used to have when it was new. Considering everything this poor little mower has been through (and all the extra $$ I've spent trying to get it going again!) I hate to just ditch it. Fuel pump arrives on Thursday and I'll give that part (along with a few squirts of carb cleaner to test for vacuum leak) a chance. I can mow with it, but it doesn't have the power it used to by any stretch - even on fairly short grass.
Summary of work:
New wiring harness
New hood (replaced via insurance $$)
New plugs (properly gapped at .030")
New (larger) fuel filter
New oil & filter
New air filter
FRESH gas
Seafoam through intake (smoked like crazy!)
New battery
New spindles
New deck belt
New transmission (replaced under warranty)
Cleaned carb (three times now!)
Adjust governor
Adjusted valve lash to within spec (.003"-.005") - this helped with starting and power, but still surges
3D printed gas tank vapor nipple
Enlarged gas tank orifice/removed tiny internal filter for more flow
Any thoughts or advice are appreciated. I'm just at a loss as to what could cause all this and I've been chasing it for better than 2 years now.
I'm at a loss and could use a little help here; I have a nice CC I bought back in 2015 and it ran like a champ. It has electric PTO (the wife insisted) and the Kohler KT735 24hp v-twin motor in it.
Fast forward just a little bit to right about this time in 2017; we had a tornado (microburst?) absolutely pummel my house and property ($140k worth of damage) which included ripping the carport I used to park my little riding mower under into shreds and flinging the resulting shrapnel for hundreds of yards. The mower appeared to have superficial damage (the entire hood assembly was ripped off and flung to who knows where and the seat was ripped up.) I put the key in and to my surprise it started right up! Unfortunately shortly after we got it going, the hydrostatic transmission died in it (it was still within warranty) so that had to be replaced at the shop.
However during the ensuing short drive once we got it back, the leads to the LED headlights were ripped from the frame and shorted out, resulting in a blown fuse. In my panic, I put in too large of a fuse and proceeded to melt the entire main harness. (Yep, that was my dumb move of the century.) I parked it in my barn and forgot it about it for several months.
Last year the grass finally grew too high and we got a notice from the city (that we don't live in, so I told them to stick it where the sun doesn't shine) and realized it was probably time to fix it. My Kubota tractor can mow for sure, but is really difficult to mow around the house with the 5' finish mower on the back. I bought a new wiring harness and replaced it, along with a new battery. Drained the gas, cleaned the carburetor and replaced the spark plugs, fuel filter and air filter. Changed the oil and filter. Bought an entire new hood assembly and replaced it. To my delight, it fired up (but not without assistance from some starting fluid.) Once it started running, it would surge, and turning on the PTO just dragged it down really bad. I checked the spindles and most of them felt like they were in bad shape so I replaced all of those, along with the belt. PTO engagement improved but still surges. It seems to idle fine hot or cold, but once you engage PTO it can't handle much grass at all. It just bogs down. With PTO off and just riding around, it seems fine.
I've since taken the carburetor off at least two more times to clean it - it doesn't appear dirty at all. Note that I'm extremely thorough at cleaning carburetors; I have an ultrasonic cleaner I sit it in for at least 30 minutes (the first run got a LOT of crud out) as well as some extremely fine needles used for cleaning 3D printer nozzles to clean the little jets in the throttle bore. The fuel cutoff/backfire preventer solenoid works as it should and the float/needle all appear in great condition. I've removed the center jet and all the little orifices are completely clean, I've also hosed it down and blasted all the little orifices with carb cleaner to ensure they're not blocked.
I did notice some oil leaking from one of the valve covers, so I took both of them off and used that opportunity to check valve lash - to my surprise three of the valves were fairly well out of clearance; anywhere from .010" to .015" which is far outside the .003" to .005" specs. Got the feeler gauges out and reset all of them to within spec and now it cranks a LOT easier and seems to have improved power a little, but still surging and still doesn't start right off the bat like when it was new.
One other area I had touched was the gas tank itself; it originally came with a strange little filter that was built-in to the tank itself, if you took the hose off the tank it was part of the nipple the hose attached to but was easily removed. This appeared to be a restriction and I noticed that crud would accumulate around the hole leading to the nipple which seemed to starve the motor a bit. I have since removed that tiny filter and upgraded to a larger fuel filter that would catch anything coming through, as well as lightly drill out the hole so that smaller particles could pass and be caught by the filter. Seems to be working well in that respect. The little nipple that passes up through the air cleaner assembly and vacuums vapors from the gas tank broke off during the storm, so I 3D printed a new one and replaced that with no affect either.
I also looked up how to adjust the governor (the external part anyhow) and did that. Didn't seem to affect anything at all. I've moved the spring up and down the different points to little effect, too.
As an additional troubleshooting measure I've ordered a new fuel pump and will replace the fuel lines just to be sure, but outside of that I'm at a loss. One other thing I haven't tried yet is to look for a vacuum leak so I'll give that a shot as well. Everything points to it running lean.
Unfortunately the hour meter was shattered during the storm too, and while I've replaced it I have no idea how many actual hours were on it.
Again, it runs great in idle with only a little surging, but lacks the power it used to have when it was new. Considering everything this poor little mower has been through (and all the extra $$ I've spent trying to get it going again!) I hate to just ditch it. Fuel pump arrives on Thursday and I'll give that part (along with a few squirts of carb cleaner to test for vacuum leak) a chance. I can mow with it, but it doesn't have the power it used to by any stretch - even on fairly short grass.
Summary of work:
New wiring harness
New hood (replaced via insurance $$)
New plugs (properly gapped at .030")
New (larger) fuel filter
New oil & filter
New air filter
FRESH gas
Seafoam through intake (smoked like crazy!)
New battery
New spindles
New deck belt
New transmission (replaced under warranty)
Cleaned carb (three times now!)
Adjust governor
Adjusted valve lash to within spec (.003"-.005") - this helped with starting and power, but still surges
3D printed gas tank vapor nipple
Enlarged gas tank orifice/removed tiny internal filter for more flow
Any thoughts or advice are appreciated. I'm just at a loss as to what could cause all this and I've been chasing it for better than 2 years now.
