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Kohler 20 hp no valve action

Discussion in 'Mechanic and Repair' started by peewee, May 22, 2004.

  1. peewee

    peewee LawnSite Member
    Posts: 43

    I just had a machine in use on friday. The guys called me and said it ran out of gas. they fueled it up and it wouldn't go. I asked if it was bone dry. they said only a small amount on bottom of tank. I figured it needed a prime or something. We put fuel in the carb intake, got no response. Checked for spark, all was well. Checked compression, 25psi. Uh Oh. Not just out of gas. So I pulled the valve cover and turned over motor, I could tell by the sound that it had no real pressure there. I noticed the push rods were not moving as the engine turned over. Is this a bad cam or something. Ideas would be helpful. Thanks.
  2. fixer67

    fixer67 LawnSite Silver Member
    Posts: 2,100

    Most 20 HP Kohler engines have hydraulic lifter like a car. You must use 10w-30 oil in them. If you use SAE 30 like you would in a Briggs the lifters will knock like the engine is going to fly apart. Try changing the oil and filter. And then try starting it. I have seen a cloged oil filter cause this because so after market filters do not have by-pass valves.Now it make take a bit for the lifters to pump up. Just remember not to burn up the starter. If the starter is too hot to put your hand on stop trying until it cools. Kohler starters have a duty cycle of 10 seconds on/ 2 minutes off. If the lifters are bad you can replace them with out engine removeal in most cases. You can download a free Kohler service manual at there web site. Good luck
  3. peewee

    peewee LawnSite Member
    Posts: 43

    Thanks fixer, I will get new oil and filter and give it a whirl.
  4. ducky1

    ducky1 LawnSite Senior Member
    Posts: 252

    I would say you have a cam problem if the lifters were not moving at all. Meybe need to have a look inside.
  5. hc841

    hc841 LawnSite Member
    from oh
    Posts: 10

    If your kohler shut down with no warning or unusual noices. And now has no valve movement. I bet you might find the crankshaft gear which is pressed on the crank got cracked and is spinning free on the crank..This is not unheard of on a kohler command with high hours...
  6. jrainw

    jrainw LawnSite Member
    from indiana
    Posts: 11

    I second hc841's comment. I have replaced cams on a few older command vtwins do to the pressed on cam gear cracking and then slipping.
  7. VegetiveSteam

    VegetiveSteam LawnSite Senior Member
    Posts: 297

    How many hours are on the engine? If it is a very low hour unit I would check for a possible flat cam. If it is a flat cam, make sure if you replace it that you replace the lifters as well. Also don't forget to use the Valspar grease that is included with the new cam. After you reassemble the engine fill it with oil and DO NOT run it above 1500 RPM for at least 5 minutes to run in the new cam. After that you can run it as normal.

    If this is a higher hour engine and you do discover a cam problem I wouldn't replace it without replacing the crankshaft as well. The crank gear and cam gear share a wear pattern which won't get along well with the new cam gear and will at minimum cause you to have a noisey engine and could also lead to the gear on the crankshaft cracking.
  8. AirCooled

    AirCooled LawnSite Member
    Posts: 30

    I agree as well. As long as both pistons are moving. Sometimes when a rod goes, the engine will run on one cylinder while slinging the broken parts around till the cam gets in the way.

    Its funny how many people don't want to admit they forgot to check the oil.

    Hope its just the crank gear. If so, replace the cam as well because the gear teeth break in together. If you don't, you may begin to loose teeth on the old cam and have more problems.
  9. peewee

    peewee LawnSite Member
    Posts: 43

    I pulled the motor today and opened up the side cover. The gear that drives the cam was cracked and spun off the crankshaft. I guess that means a new crank. :( Sounds expensive. I am waiting for a price from the dealer. You are suggesting that I also replace the cam? Sounds even more expensive:eek:
  10. peewee

    peewee LawnSite Member
    Posts: 43

    1500 hours approx. on this motor

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