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Exmark Lazer Z Kohler CH740 problems

#1

N

NxtGoRnd

Hi everyone thanks in advance for any help. I have a Exmark Lazer Z with Kohler Command SP27 model CH740s Spec PS-CH740-0045 serial 3416109201. Sometime around 2015 it started blowing oil and skipping so I put it in my building and started to use and older mower I had. I had been through cancer and chemo and dealing with chemo brain lol. Pulled it out couple weeks ago and dug in , the oil was leaking from the gasket at the crank case vent. I replaced gasket and filter, installed new plugs, oil change serviced it and fired it up. It ran for about 30 minutes of cutting doing excellent then lost power.

I took it to the building and it would idle but at full throttle pop through the carbs like maybe no timing advance. I ordered and updated the coils to the new Kohler style and removed the DSAM ignition and coils. It was still doing same thing. Checked Leak down and both cylinders were 80/75 and compression on both was 150 with engine cool, I would think even higher on a warm engine. I ordered a carburetor and installed same results with both carbs. Any pointers or suggestions would be greatly appreciated still dealing with chemo brain and old age so cognitive skills not what they used to be. Thanks again Tony


#2

M

mechanic mark

www.kohler-engine-parts.opeengines.com

Free Kohler Service Manual Downloads - OPEengines.com

Listed below are Kohler engine service repair manual in Adobe PDF format that you can download for free. Below we have provided a link to these manuals which can also be download. Click on your engine listed below to download. These service manuals provide general information, adjustment...
www.kohler-engine-parts.opeengines.com
See page 18 in CV740 Service Manual above, Troubleshooting Section. Please take your time & let us know how it goes, thanks Mark


#3

S

slomo

NxtGoRnd said:
Hi everyone thanks in advance for any help. I have a Exmark Lazer Z with Kohler Command SP27 model CH740s Spec PS-CH740-0045 serial 3416109201. Sometime around 2015 it started blowing oil and skipping so I put it in my building and started to use and older mower I had. I had been through cancer and chemo and dealing with chemo brain lol. Pulled it out couple weeks ago and dug in , the oil was leaking from the gasket at the crank case vent. I replaced gasket and filter, installed new plugs, oil change serviced it and fired it up. It ran for about 30 minutes of cutting doing excellent then lost power.

I took it to the building and it would idle but at full throttle pop through the carbs like maybe no timing advance. I ordered and updated the coils to the new Kohler style and removed the DSAM ignition and coils. It was still doing same thing. Checked Leak down and both cylinders were 80/75 and compression on both was 150 with engine cool, I would think even higher on a warm engine. I ordered a carburetor and installed same results with both carbs. Any pointers or suggestions would be greatly appreciated still dealing with chemo brain and old age so cognitive skills not what they used to be. Thanks again Tony
Click to expand...
I feel you are way above most of the unsick cancerless folks we get on here. Cheers to you and keep up the good fight!!!

Popping through the carb is either early ignition timing, water in the gas or a blown head gasket. I'm not a Kroller expert like several others on here. Sticking intake valve??? Valves out of spec?

Verify good clean fuel from an aux fuel tank and lines to the carb. Rule that out. Then do a valve adjustment or yours might have hydraulic lifters maybe. Check your engine manual.


#4

N

NxtGoRnd

slomo said:
I feel you are way above most of the unsick cancerless folks we get on here. Cheers to you and keep up the good fight!!!

Popping through the carb is either early ignition timing, water in the gas or a blown head gasket. I'm not a Kroller expert like several others on here. Sticking intake valve??? Valves out of spec?

Verify good clean fuel from an aux fuel tank and lines to the carb. Rule that out. Then do a valve adjustment or yours might have hydraulic lifters maybe. Check your engine manual.
Click to expand...
Thanks for the reply it has hydraulic lifters a new carb and two tanks of ethanol free gas couple weeks old. Have wondered if it could be a lifter and checked the push rods they are straight and undamaged. Sticking lifter still a possibility. compression and Leak down test should rule out head gasket but I replaced both cylinder head gaskets just because LOL. Thanks and Cheers.


#5

N

NxtGoRnd

mechanic mark said:
www.kohler-engine-parts.opeengines.com

Free Kohler Service Manual Downloads - OPEengines.com

Listed below are Kohler engine service repair manual in Adobe PDF format that you can download for free. Below we have provided a link to these manuals which can also be download. Click on your engine listed below to download. These service manuals provide general information, adjustment...
www.kohler-engine-parts.opeengines.com
See page 18 in CV740 Service Manual above, Troubleshooting Section. Please take your time & let us know how it goes, thanks Mark
Click to expand...
I will check that out thanks! I have downloaded the service manual and parts manual for the CH740. Thanks again.


#6

V

VegetiveSteam

NxtGoRnd said:
Hi everyone thanks in advance for any help. I have a Exmark Lazer Z with Kohler Command SP27 model CH740s Spec PS-CH740-0045 serial 3416109201. Sometime around 2015 it started blowing oil and skipping so I put it in my building and started to use and older mower I had. I had been through cancer and chemo and dealing with chemo brain lol. Pulled it out couple weeks ago and dug in , the oil was leaking from the gasket at the crank case vent. I replaced gasket and filter, installed new plugs, oil change serviced it and fired it up. It ran for about 30 minutes of cutting doing excellent then lost power.

I took it to the building and it would idle but at full throttle pop through the carbs like maybe no timing advance. I ordered and updated the coils to the new Kohler style and removed the DSAM ignition and coils. It was still doing same thing. Checked Leak down and both cylinders were 80/75 and compression on both was 150 with engine cool, I would think even higher on a warm engine. I ordered a carburetor and installed same results with both carbs. Any pointers or suggestions would be greatly appreciated still dealing with chemo brain and old age so cognitive skills not what they used to be. Thanks again Tony
Click to expand...
It almost acts like there is an exhaust restriction but let's start simple. Can you give us the part number you used to update the ignition coils? It should have been a kit with two MDI ignition models and a white wire pigtail for the kill.


#7

H

hlw49

NxtGoRnd said:
Thanks for the reply it has hydraulic lifters a new carb and two tanks of ethanol free gas couple weeks old. Have wondered if it could be a lifter and checked the push rods they are straight and undamaged. Sticking lifter still a possibility. compression and Leak down test should rule out head gasket but I replaced both cylinder head gaskets just because LOL. Thanks and Cheers.
Click to expand...
Cylinder leak down test and compression test may not show either one of these even a crankcase vacuum test will not do it. In my experience with Kohler engines these test rarely do. Due to area they blow. The best indicator of a blown head gasket is the plugs will be black and oily and my use oil or may not. They blow between the oil return hole and the cylinder a very small area. Sometimes they blow outside the cylinder in the exhaust port area. Did you lap the heads down so they are flat? Could be an air leak.


#8

N

NxtGoRnd

hlw49 said:
Cylinder leak down test and compression test may not show either one of these even a crankcase vacuum test will not do it. In my experience with Kohler engines these test rarely do. Due to area they blow. The best indicator of a blown head gasket is the plugs will be black and oily and my use oil or may not. They blow between the oil return hole and the cylinder a very small area. Sometimes they blow outside the cylinder in the exhaust port area. Did you lap the heads down so they are flat? Could be an air leak.
Click to expand...
The factory gaskets were in great shape i found no evidence of any leaks, I installed the new gaskets it has same condition. I did not lap I have taken the engine back out again and will go back over everything. I did hook a remote to starter while it was on the bench this morning and turned it over with a car battery while listening with stethoscope (plug wires off). the number 2 cylinder plug has been a little black compared to the #1 cylinder every time I have checked. It will run with either plug disconnected and makes a difference when you pull either one. Thanks for the input will keep all posted as I go.


#9

N

NxtGoRnd

VegetiveSteam said:
It almost acts like there is an exhaust restriction but let's start simple. Can you give us the part number you used to update the ignition coils? It should have been a kit with two MDI ignition models and a white wire pigtail for the kill.
Click to expand...
I actually put new old stock replacements then went to 25-707-03-S Came with Kohler sticker said genuine Kohler parts. I removed the old dsam and followed directions it did have the ground wire and disconnect 12 volt wire. Thanks for the help for sure and and you are correct on exhaust restriction. Oh sorry for the delay in answering. Cheers Tony


#10

N

NxtGoRnd

As VegetiveSteam correctly suggested exhaust restriction. I turned it over with the valve covers off and #2 Cylinder head exhaust valve was not moving so yep restriction. I tightened the rocker bolt another 10 in lbs and when I turned it over the exhaust valve was opening. All bolts including rockers had been torqued to spec not saying my torque wrench was dead on. Put everything back and attempted to run it it ran same as before I removed the valve covers and the same #2 exhaust was not moving. I removed the rocker and pushrod pulled the lifter and bench bled it in the press put it back torqued it up same results. I have a set of lifters on order but concerned there was not much oil spillage when running at idle with rocker covers off. I checked the oil pressor sensor and it was working correctly. I have fuel service gauges, leak down gauges, compression gauges and others but nothing to check oil pressure with will get something this afternoon. I can push the valve in by hand and it springs back in place once i release it so failed lifter ? Once again thanks to everyone! Tony


#11

V

VegetiveSteam

If you're not hearing the lifters clattering your oil pressure is probably okay. On the Command twins, lifter tick is usually the first sign of low oil pressure. You also won't see much oil running with the rocker covers off. There is no pressurized oil in the upper end. Are you torquing the rocker arms to 160 in lbs?

If you turn the engine over by hand do all of the rocker arms seem to move the same amount once you re-torque them? I doubt this would be your issue but check if they all move the same so you can rule out a flat cam lobe.


#12

N

NxtGoRnd

VegetiveSteam said:
If you're not hearing the lifters clattering your oil pressure is probably okay. On the Command twins, lifter tick is usually the first sign of low oil pressure. You also won't see much oil running with the rocker covers off. There is no pressurized oil in the upper end. Are you torquing the rocker arms to 160 in lbs?

If you turn the engine over by hand do all of the rocker arms seem to move the same amount once you re-torque them? I doubt this would be your issue but check if they all move the same so you can rule out a flat cam lobe.
Click to expand...
The other intakes are moving the same the other exhaust seems fine I pulled the lifter and the cam does not look very worn. Saying that I know it is not proper measurement the plug on #1 side looks normal and the #2 side is black. I think the cam is okay. I did torque to 160 inch pounds.


#13

N

NxtGoRnd

Installed new lifter still getting same results swapped the rocker pushrod and lifter from a different valve same results. I believe I have a worn cam lobe on #2 exhaust man wish I had started there LOL. As said first post cognitive abilities have definitely gone down hill, thinking I will put in a cam but apparently there are no oil pumps available. Seems discontinued and no replacement hate to install cam and not oil pump. Pump #2401226S have not been successful at finding aftermarket either.


#14

V

VegetiveSteam

NxtGoRnd said:
Installed new lifter still getting same results swapped the rocker pushrod and lifter from a different valve same results. I believe I have a worn cam lobe on #2 exhaust man wish I had started there LOL. As said first post cognitive abilities have definitely gone down hill, thinking I will put in a cam but apparently there are no oil pumps available. Seems discontinued and no replacement hate to install cam and not oil pump. Pump #2401226S have not been successful at finding aftermarket either.
Click to expand...
The 24 012 26-S should be the camshaft. The oil pump # should be 24 393 53-S and like you mentioned it is discontinued. The only way to get an oil pump from Kohler now it to buy the complete closure plate assembly. Might check ebay for the pump. If I hadn't thrown them away I would have given you an oil pump. I had two from one of my schools brand new in the box sitting around for a few years. After I retired I got tired of looking at them and cleaning up some junk in the basement last year they found their way to the trash. I guess I should have put them on ebay. Being NLA they would have probably gone fast.


#15

V

VegetiveSteam

If you do find out it is a flat cam lobe and you are the original purchaser and you have a receipt showing the purchase date, I'd contact Kohler tech service and explain everything just like you did here. You can call them at 920-459-1579 or you can go to kohlerengines.com and leave them a message there. They will get back to you.

I'm guessing the unit has the same amount of hours on it as it did when you stopped using it in 2015? Your engine was built in June of 2014 and you stopped using it in 2015 so you can't have but maybe 50 hours on it if that many unless you were using it commercially. There is nothing a user can do to cause one flat cam lobe. If you can do the work yourself, see if Kohler will do a Policy Adjustment for parts only. The worst they can do is say no but I feel it's worth a shot.


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