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jimmyf21

craftsman with kohler cv15s won't run

Jimmy Forester
9 years ago

I have a craftsman lawn mower that won't run. It had been really hard to start and then one day wouldn't start at all. I did a compression check and it was showing about 60 psi. I figured out it had a blown head gasket. Im not real experienced with working on motors, but i tore the top end apart and replaced the head gasket. Did another compression check and it was only up to about 70 psi. I started it up and it ran really rough. It could barely could stay running at all. Now i just went out and bought a leak down tester. The gauge reads that it is good, but i could hear some air in the bottom end. Ive read that a little bit is normal, so im not sure if i have a normal amount or not.

Is 70 psi enough compression to run? Anything else i could try?

Comments (4)

  • tomplum
    9 years ago

    You will not get a true answer to your question due to the compression release. Plus, had you covered some of the basics here. IE is the choke closing? Tried a new spark plug or dropped the bowl to see what's in the carb? Try this. Remove the air filter and give a 2 second blast of carb spray in through the carb and crank. Does it try to up and run?

  • mownie
    9 years ago

    Your reading of 60-70 PSI on a compression gauge while cranking is only indicative of a properly operating compression release mechanism. The ACR is effective below 700 RPM and cranking speeds are are usually around 400 RPM or so.
    I think you have been chasing a red herring or a wild goose (regarding the compression).
    The ACR is why a leak down test is best for determining suspected compression losses.
    Did your engine seem to be cranking really fast? If compression loss was an issue, the engine would have seemed like it was really spinning fast when cranked, kinda like when you spin an engine with spark plugs removed.
    Have you tried spraying a 2 second shot of carburetor cleaner or pouring a spoonful of gasoline into the carb throat to see if it wants to start up and run well for a couple of seconds before it dies? Try that, and if the engine acts like it really wants to run well (for a couple of seconds), then you have a fuel delivery problem.
    Have you tried a new spark plug? Beware, testing plugs when they are removed from the engine can give false results.
    A bad plug might show a spark if removed and laid against the engine and the engine cranked. But the same plug might not be sparking at all while under the influence of compression in the combustion chamber.

  • mownie
    9 years ago

    tomplum types much faster than I do.

  • Jimmy Forester
    Original Author
    9 years ago

    I was chasing my tail on this one. Before I found the head gasket issue, I had tried messing with the spring that connects the throttle cable to the governer bracket. Turns out my "improvement" to the spring was the problem. After I replaced the head gasket it was running horrible and bogging and dying because it wasn't getting any throttle

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