Kaw 13HP Twin Cycl. Starts Hard

Discussion in 'Mechanic and Repair' started by ed2hess, Feb 25, 2013.

  1. ed2hess

    ed2hess LawnSite Fanatic
    Posts: 13,079

    FH381V AS29-R. The machine doesn't want to start after sitting over nite. If I put a small squik of quick start away it goes. And it will start on almost the first pull the rest of day. New plugs, new gas filter, valves set, carb overhaul last year.

    As an experiment I shut off the gas from the tank and let the machine run until it died. The fuel filter was on the pump side of the cut off and it was not sucked dry when engine stopped:confused: Then I opened up the fuel cutoff and the machine wouldn't start until I hit it with quick start. I am leaning heavy to fuel pump, am I correct? Unit is going into fourth year. Both spark plug coil replaced last year.
     
  2. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024

    Ed,

    The fuel filter will not empty because you closed off any way for the pump to suck any air, It's got to get air to empty a filter. The fact it wouldn't start after you reopened the valve is because you ran the float bowl empty, Otherwise it takes a half dozen pulls to re-fill the bowl for start-up.

    Check the choke butterfly and make sure it's closing FULLY when choke is applied.....
     
  3. ed2hess

    ed2hess LawnSite Fanatic
    Posts: 13,079

    Ok that all makes sense. The chokea is dead closed absolutely necessary
    on this unit. I can pull until I get tired and it will not start. One little bitty squirk of ether and away she goes. And I can shut if off and on at intervals of about 10 minutes and it starts right up. But after 12 hours no startee. Fuel filter is new.
     
  4. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024

    Take a look inside the spark plug boots and see if there's any rust or corrosion.....
     
  5. ed2hess

    ed2hess LawnSite Fanatic
    Posts: 13,079

    I will look but this unit had the spark plugs replaced and I use a diaelectric when I put the wires back on. The wires are less than a year old but I will take another look. At least one side should fire.

    I am hoping you don't suggest I go into that carb. It has that little hidden chamber that you have to pry the lid off then glue it back. I don't like gluing inside a carb. By the way I checked to be sure it wasn't leaking fuel into the carb overnite but it was dry as a bone.
     
  6. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024


    Huh, I've never heard of such or done anything like that ?

    Is it shown in this pic ?

    [​IMG]

    How many hours are on this engine..... Guestimate ?

    There's a few things that could be causing this, Low/weak compression (not pulling enough fuel when cold), Slightly restricted main circuit in the carb, Weak spark when cold even though the coils were replaced. Leaking intake manifold gaskets, It's just going to be a process of elimination until you find the culprit.....
     
  7. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,240

    As RestroRob stated...without knowing the hours on the engine...its a tough call....
    Being that it is a Kaw Twin...I would check the valve adjustments..
    Adjusting the valves seems to fix a lot of different problems...
     
  8. ed2hess

    ed2hess LawnSite Fanatic
    Posts: 13,079

    When I get unit back to my place I will pull carb and take picture of chamber.
    Hours about 700. Temp here is aroun 60F. On the intake manifold gasket is it possible to get ether spout near them to squirt when running?


    I did adjust the valves this winter. Don't know if it was starting hard
    all summer and not reported to me. I will recheck the valves.
     
  9. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,240

    Ed....adjusting the choke has fixed 90% of the kaw engines I have come across that are experiencing the problem you have...
    It might also be an intake gasket leaking...is one or both of the sparkplugs whitish.??
     
  10. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,240

    Another thing to check is the airgaps on the coils...
    If the coils are too close to the flywheel...you will have a weak spark when the engine is cold..
    When the engine warms up...the engine expands the airgaps from .002 to .004.....allowing the engine to start every time...
     

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