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Kohler CH20 Flywheel Compatibility

Discussion in 'Mechanic and Repair' started by Snyderserv5060, Oct 24, 2012.

  1. Snyderserv5060

    Snyderserv5060 LawnSite Member
    Messages: 194

    I posted a week or so ago about a leaf vac I purchased that needed a bunch of work. With some time and a lot of parts that I fortunately had from other motors in the shop I was able to get it all up and running.

    I know that piston slapper on here verified in the other post that most of the ignition parts would be interchangeable, at least enough to verify that the engine would still run (thanks for your help with that). After reading around the internet some last night I came to find that some of the kohler command flywheels are the exact same size but have slightly different timing than others do.

    Piston Slapper or anyone else who may know. Is it going to be a problem that the stock flywheel was a 24-025-55-S off the 20hp motor and I have a 24-025-58-S off a 27hp motor I had as parts? The 27hp had the smart timing (or whatever its called by Kohler) while the 20hp I do not believe does. I just dont want to put it all back together this week only to find out the difference in timing causes it to run hot and cause damage. Unfortunately the original flywheel is rough from mice, exposure to the elements and not all the magnets are on it. Id rather not drop $150 on a flywheel if the 27hp works fine/safely but id rather do it now than regret it later.

    Thank you
  2. piston slapper

    piston slapper LawnSite Platinum Member
    Messages: 4,329

    Kohler makes a bunch of different flywheels...
    The key is not to mix the flywheels with different coils...
    If you use the DSAI 27 hp flywheel...you got to use DSAI coils and harness
    The plain jane ignition that used standard inductive coils was available on 18 to 25 hp engines...
    Off the top of my head...here's how to identify the more common Kohler Command twin flywheels...
    Look a the flat area around the crankshaft hole..
    If it has no drill mark it is standard ignition
    If it has a slightly drilled hole...kinda like a dent..its DSAM
    If it is drilled all the way through its DSAI
    The newer DSAI flywheel has vents molded into it...not solid across the top.
    Posted via Mobile Device
  3. Snyderserv5060

    Snyderserv5060 LawnSite Member
    Messages: 194

    Ill have to look tomorrow when its light out. I did run the OEM CH20S version coils and NOT the CH740 coils/harness when reassembling it. The 20hp has far less wiring and has the key switch built into the motor shroud since its on a leaf vac. The 27 being off a Lazer Z had a wiring harness that goes into the mower and had a bunch more wires on it. Since I mixed the coils and different flywheel my guess is that im going to need to source the proper flywheel. Or alternatively find a 27hp motor that has the wiring harness made to clip into a key switch on the engine and go back to the 27 coils with 27 flywheel.

    I will lay them out tomorrow and look at them as you recommended. Thanks again
  4. piston slapper

    piston slapper LawnSite Platinum Member
    Messages: 4,329

    Easy enough to hook the 27hp wiring to the key switch...
    The back of the switch is labeled...either on the prongs or beside them..
    S. Start. R. Run....B..Battery...L..Line (keyed power). G...ground. (kill wire)
    Use a small screwdriver to release the wires from the plastic connector .
    Posted via Mobile Device
  5. Snyderserv5060

    Snyderserv5060 LawnSite Member
    Messages: 194

    Easy enough. Looks like I have some work to do tomorrow after work. I have the harness off the 27 so that would work.
  6. piston slapper

    piston slapper LawnSite Platinum Member
    Messages: 4,329

    If you have enough of the same flywheel magnets ....they made 2 or 3 different shapes and sizes....you may be able to repair the 20hp flywheel...
    Check the current kohler needs help thread...
    Posted via Mobile Device

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