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Losing power momentarily

#1

S

scgarrett3037

Hello,

I have a 2008 Grasshopper 227 mid-mount mower with a Kohler Command Pro 27 Gasoline engine. Totals hours are 580.

My problem is.....I lose power during operation. The engine RPMs will reduce about 25% and of course the blades slow down movement of the mower is slowed. It doesn't matter if the PTO is engaged or not. Then all of a sudden it seems to clear itself up and everything is fine until the next time. Sometimes this reduction in power lasts a few minutes and other times it might last 30 minutes.

I have replaced the fuel filter, both air cleaners, and I also replaced all three belts and the problem still exists. Tonight I'm going to replace the spark plugs. I've check fluid levels and all are ok.

Does anyone have any thoughts or ideas on resolving this issue.

Many thanks,

Steve


#2

Ronno6

Ronno6

I had experienced similar problems with a Briggs Vanguard V-twin.
It would have 1 cylinder drop out, but usually came back after a few seconds.

I finally was able to determine that I was losing spark in one cyl.
I ultimately replaced the coil for the intermittent cylinder as well as the other one "for good measure."

YMMV


#3

S

scgarrett3037

Thank you Ronno6 for your suggestion. I will check my coils at the earliest opportunity and report back.
Steve


#4

Ronno6

Ronno6

The Kohler ignition is considerably more sophisticated than the Briggs.
Your coils are connected to a module which controls the timing of the spark depending on RPMs.
The kill wire appears to connect to the module rather than the individual coils, so I would not suspect the kill circuit.
But, there could possible be a problem with the wiring between the module and each coil?

Problem is that troubleshooting an intermittent problem is always difficult.
I was only able to get a handle on mine when the cylinder dropped out ling enough so that I could investigate.

I have no experience (yet) with Kohler engines (got one coming on a new Hustler mower.)
I'm sure there are many members who have experience with Kohler.


#5

S

scgarrett3037

Just wanted to update on my problem...
I have now replaced both air cleaners, cleaned carburetor, replaced fuel filter, replaced spark plugs, and replaced all three belts. The engine now doesn't reach full power at all and when engaging the PTO it really struggles to turn the blades. I'm worse off now than I was before! Belts are adjusted to specs. Accessing the coils/modules requires more disassembly than I want to do at this time. Could this be clutch related?


#6

Ronno6

Ronno6

How freely does the deck system (pulleys,spindles,clutch and belts) move when not engaged?
It is possible that a spindle bearing or idler or tension pulley has tightened up as a prelude to seizing.


#7

B

bertsmobile1

scgarrett3037 said:
Just wanted to update on my problem...
I have now replaced both air cleaners, cleaned carburetor, replaced fuel filter, replaced spark plugs, and replaced all three belts. The engine now doesn't reach full power at all and when engaging the PTO it really struggles to turn the blades. I'm worse off now than I was before! Belts are adjusted to specs. Accessing the coils/modules requires more disassembly than I want to do at this time. Could this be clutch related?
Click to expand...

Well you have either not cleaned the carb, reassembled the carb wrong or hooked it up wrong.
Commands have hydraulic lifters which don't need adjusting but they still have pushrods that bend and valves that stick.
If the engine does not come up to full revs with no load then it is not going to be any better when you engage the blades.

So why are you bothering to to even think about the clutch.

You have made a mistake when you did the service, we all do that from time to time because none of us are God so go back & recheck what you have done.


#8

S

scgarrett3037

"How freely does the deck system (pulleys,spindles,clutch and belts) move when not engaged?" ..... The pulleys, belts, blades turn easily when not engaged.

"Well you have either not cleaned the carb, reassembled the carb wrong or hooked it up wrong." ..... I didn't remove the carb, I just sprayed cleaner down the throat.

Does anyone know if there's any way of checking the fuel pump for proper operation? I forgot to mention that I have blown out all fuel lines when I replaced the fuel filter.


#9

Ronno6

Ronno6

Does anyone know if there's any way of checking the fuel pump for proper operation? I forgot to mention that I have blown out all fuel lines when I replaced the fuel filter.
Click to expand...

If your engine is running, I personally would not suspect the fuel pump.
But, as your problem now appears to be continuous, it may be easier to diagnose.
As Bert indicated, since it is worse since you worked on it, you may have affected the troubled part, albeit in a negative manner........


#10

dfbroxy

dfbroxy

Ronno6 said:


If your engine is running, I personally would not suspect the fuel pump.
But, as your problem now appears to be continuous, it may be easier to diagnose.
As Bert indicated, since it is worse since you worked on it, you may have affected the troubled part, albeit in a negative manner........
Click to expand...


If it is running on all cylinders, try checking and adjusting the governor.


#11

S

scgarrett3037

update on problem.....

I checked for spark on both plugs using an in-line spark plug tester. The spark plug on the left side appears good, however the right plug seems intermittent or goes so weak you can't see it during the day. I also found out the hard way that during the periods of weak or nonexistent spark the coil/ignition module (wire) is grounding to the engine block. So I'm guessing that a plug wire or connection wire has frayed and touches the engine block.

To reach these ignition modules, you have to pull the engine shroud......in order to do that, it looks as though the engine has to be pulled. My Kohler CH740 is a horizontal shaft and there is just no room in the Grasshopper to work on it.

Can anyone provide a picture of my engine (Kohler CH740S) with the shroud off and showing the ignition modules?


#12

willys55

willys55

scgarrett3037 said:
"How freely does the deck system (pulleys,spindles,clutch and belts) move when not engaged?" ..... The pulleys, belts, blades turn easily when not engaged.

"Well you have either not cleaned the carb, reassembled the carb wrong or hooked it up wrong." ..... I didn't remove the carb, I just sprayed cleaner down the throat.

Does anyone know if there's any way of checking the fuel pump for proper operation? I forgot to mention that I have blown out all fuel lines when I replaced the fuel filter.
Click to expand...
spraying carb cleaner into the carb is not cleaning it or helping it in anyway.........remove it, disassemble and replace all parts including the float, soak it over night in a cleaning solution...reassemble and adjust the metering screw.............then you will see a difference.


#13

EngineMan

EngineMan

This may help you

Attachments







#14

S

scgarrett3037

Thank you all for your responses and suggestions. They were very helpful. Tomorrow I will disconnect the engine and pull it to get at the engine shroud. Once that shroud is removed, I'll be able to get to the ignition module.
Steve


#15

S

scgarrett3037

In Conclusion......

I replaces the two DSAI ignition modules with new MDI modules plus a kit which comes with the new modules. Tightened every thing up and added oil and it fired right up. Sounds great and is providing full power. Issue resolved. Thanks to all for your suggestions. Steve


#16

EngineMan

EngineMan

Well done and thank you for the feedback.:thumbsup:


#17

Ronno6

Ronno6

I love it when a plan comes together.......

We appreciate your appreciation.


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