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Kawasaki FH721 got gas and spark but no start

Discussion in 'Mechanic and Repair' started by Mashburn, Mar 14, 2011.

  1. Mashburn

    Mashburn LawnSite Member
    Posts: 3

    I just bought a bush hog M2561K zero turn mower from an auction a few days ago. The mower would not start before the auction and I thought that it was severely flooded but the plugs were firing. There was gas sitting in the carburator when I took off the intake hose but when the plugs were removed they were bone dry. A cup full of gas was dumped into the carb. and it fired right up and ran fine. Next day.... same thing, except harder to start. Any ideas? Engine has 430 hrs and I figure that the valves have never been adjusted. Also the solenoid on the carb. is working, at least I can feel it clicking. Any help will be appreciated.

    FIXDISS LawnSite Senior Member
    Posts: 445

    If it will fire up when you put gas in the carb then you have a fuel delivery issue.If the unit has sat for a while then chances are the carb is gummed and will need to be cleaned.You might be able to just remove the bowl and clear it out as well as checking the operation of the float,needle and seat. Also use s blast of carb cleaner to clear the main jet.
  3. weapons of grass destruction

    weapons of grass destruction LawnSite Member
    Posts: 228

    Yes clean the carb go to advance or a auto parts store and get a carb cleaner that is in a 1 gallon paint can. Take all gaskets and take out the float.
    bowl and all jets let sit for 1 hour and blow out with some air and reinstall on mower.
  4. Mashburn

    Mashburn LawnSite Member
    Posts: 3

    When I place my hand over the intake of the carb, I get gas sucked up into the carb. The problem is that it seems like the fuel isn't getting from the carb to the cylinders. Even pouring gas into the carb didn't make it start right away, actually it wasn't until I sprayed starter fluid directly into the cylinder via the spark plug hole that the engine started. Once the engine starts, it idles and runs very well. Something just isn't adding up. Today I am going to clean the carb and adjust the valves. Any other ideas?
  5. RickyDL77

    RickyDL77 LawnSite Senior Member
    Posts: 431

    since you purchased second hand
    1. new plugs
    2. new oil/filter
    3. drain gas and add premium to ensure good fuel
    4. new fuel filter and air filter

    no telling how long this machine sat up or how well it was maintained.

    Start by cleaning the carb, more than likely it's mucked up. And make sure the choke plate is adjusted correctly (closes all the way with choke on)

    Valves just a little bit off can cause it being hard to start. also if the starter acts like it's dragging it will make things difficult. Usually those kawasaki's backfire when the valves are off enough to cause issues....but only while starting in most cases.

    Can check the intake gaskets to make sure they arent sucking air, once you get it running.... with some carb cleaner spray, i wouldnt use Ether..just spray arround the gaskets lightly @ low idle and see if rpms change.

    it can be a number of things..start with the carb and gas so we can rule out the most likely culprit. Goodluck.
  6. Mashburn

    Mashburn LawnSite Member
    Posts: 3

    OK, I adjusted the valves to .004"IN and .006"EX, the intake valves were very close but the exhaust valves had about .015" clearance. I'm not sure that this had anything to do with how poorly it has been starting. It's got fresh filters and fresh gas and oil. I took the bowl off of the carb and it was very clean, no sign of old gas or varnish. After that I tried to start it with no luck until I poured a couple of tablespoons worth of gas directly into the carb. The engine spit and sputtered and puffed black smoke just like I expected it to but any smaller amount of gas and it wouldn't hit a lick. The plugs don't look like they are firing as strongly as they should but once the engine starts, it runs very well. I can't see where the carb has any kind of adjustment besides idle...never seen one that didn't before. Ignition timing has to be ok or else it wouldn't run right? If anyone has had a similar problem, please post!

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