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Problem with a Kohler on a Walker Mower? Help?

Discussion in 'Mechanic and Repair' started by TOSLC, Oct 29, 2006.

  1. TOSLC

    TOSLC LawnSite Member
    Messages: 175

    I have a 99 Walker CGHS that has a 16HP VTwin Kohler. About 1700 hours and has run perfectly up to this point. I mowed two weeks ago and brought the mower into the shop hot, shut it off, and it Back fired. No big deal I went into the house not giving it a second thought. Well the next time I go to use it the mower only wants to run on one cylinder. To make a REALLY long story short I'll list what I've done to this point, and hope that someone has some idea's.

    Two new Kohler Coils
    Two new spark plugs (Swaped them from Cyl to Cyl - no change)
    Flywheel Key is fine
    Compression Checked (Cyl #1 = 120psi, Cyl #2 = 100psi)
    Cylinder Leak Down - Moderate range (good for 1772hrs)
    Cranked over engine with valve cover off - Both valve's moving

    I'm at a loss here, and could really use some advice before I throw any more $$$ at it. Like I said I think it might of had something to do with the back fire because it ran perfect to that point. It's cylinder #2 that's missing out, and one more thing to add is if I cover the exaust port while it's running, it trys to fire that cylinder more often?

    16Hp Vtwin Kohler
    Family: TKH574U1G2RA
    Model: TH16S
    Spec No: 52518
    Displ (cc): 520
    Serial: 2816000761
  2. tomo

    tomo LawnSite Senior Member
    Messages: 660

    hello, although i am not familiar with the 16hp twin if it is the same as 20--25--26 hp spray carb cleaner over inlet manifold where it joins to clinder head . This can be done while engine still in machine . This checks 4 vacumn leaks at the relevant cylinder .

    Other way is also balance check . Principle is to see which cylinder is doing the most /least work .
    1/ leaving both plugs in
    2/connect inductive tacho to cyl to cylinder AA
    3/ remove opposite cylinder spark lead and install spare plug .Earth to ground the body of the plug eg using jumper lead. Cylinder BB
    4/ start engine and take reading of tacho
    5/the cylinder BB work rate can now be checked note rpm drop compared to idle
    6/swap tacho ,reconect BB ,install tacho BB, earth plug lead AA as described b4
    7/ note rpm drop compare readings and you will find the cyl doing the least work

    COMPRESSION CHECK --found best/consistant results if both plugs are removed first. Crank an even number of times. 130--150 would be nice.
    7--9 compression strokes.

    Check 4 presence of vacumn in crank case ,only small amount required if positive pressure, compression pressure is in the crank case via rings or head gasket .

    Remote possibility is blocked exhaust on that cylinder

  3. TOSLC

    TOSLC LawnSite Member
    Messages: 175

    I'm 99.7% sure that cyl#2 is the one not firing. The engine actually runs better with the #2 plug wire unplugged, than it does with it plugged in. It won't run at all if you unplug the #1 wire (with #2 plugged in of course).

    Spraying carb cleaner around the intake is an interesting idea though. Maybe the backfire blew out part of the intake gasket and it can't get fuel like it's supposed to? I'm at work right now, but I'll try it as soon as I get home . . . at this point I'm up for about anything.

    Any help is appreciated and I will post back what fixed it.
  4. pugs

    pugs LawnSite Gold Member
    Messages: 3,024

    This engine is not like the 20...25...30 whatever. This is Kohlers Overhead Cam engine. Honestly I have only ever seen one. It resides down the street from me on a Walker. Heck of a time finding the right air cleaner for it...LOL

    Unfortunately I know very little about that engine. It could be an intake leak but its hard to say. 120 vs 100 for compression is a decent enough difference to be a bit concerned.

    What type of leakdown tester are you using. What percent was the leakage. Moderate isnt really detailed enough. And where is the leakage air going? Intake, exhaust or crankcase?
  5. topsites

    topsites LawnSite Fanatic
    Messages: 21,653

    You might not want to do this yet but before you give up, and you also need to do this during the early afternoon due to noise but...

    Seeing how it backfired (through the muffler, yes?), it is possible something came off inside the muffler and is clogging...

    So, remove the entire muffler but before you play with it, with the muffler off first inspect the exhaust port to make sure it is clean but WAIT!

    - Look IN the port and make sure you see the Cylinder WALL!!! If the wall of the cylinder is not completely covering the hole, turn the engine over by hand (a little cranking) until the wall of the cylinder completely covers that hole!
    - Then, blow it out with compressed air and maybe take a screwdriver to scrape some things but watch it do NOT touch that cylinder wall!

    Now, with port clean and muffler off the engine, start it and RUN but ...
    well it's kinda loud lol
    But, if it runs ok with the muffler off, then your problem is a clogged muffler.
    see what that does thou, it eliminates one more possible problem.
  6. walker/redmax

    walker/redmax LawnSite Senior Member
    Messages: 366

    Was your mower running low on oil? I know it sounds obvious but one time I had a 20hp that was burning oil and I let it get too low and the second cylinder ceased up. I ended up having to replace the engine. I hope that its not anything as serious as this!:waving:
  7. TOSLC

    TOSLC LawnSite Member
    Messages: 175

    Pugs - Yes the engine is OHC and kinda hard to find parts for. One dealer I went to looking for the coils wanted to argue that the model number was wrong. But it's an engine Kohler builds for Walker. I wasn't that concerned with 20psi difference since they are both over 100 . . . but I'll consult the dealer about maybe a "minimum"? Also I'm not sure what brand the leak down tester was (borrowed from dealer), it just had a gauge that read "Good, Moderate, and Fail". Also not sure where it was going, but I'll do more tonight.

    Topsites - I had the muffler off when I put a rag over the exhaust port to see what the pulses felt like. That's when it tried to fire more? And with it being overhead cam and valve I'm not sure I'll be able to see the piston or wall. But I'll look at that as well when I get home.

    Walker/Redmax - It could have run low on oil (because it does burn some) but I check it everytime before I use it. I added some before that run. And added some (maybe 2 or 3ozs) before the problem occured, but I don't remember it being an excessive amount (more than usual anyway). Also I know the piston is moving because I checked TDC before the leak check. But it could be scuffed and causing drag?
  8. pugs

    pugs LawnSite Gold Member
    Messages: 3,024

    Ummm...you will never see the cylinder wall. Its a 4 cycle engine. It has something called valves....

    Kohler didnt make it just for walker but it just never caught on. They had some issues when they first came out and didnt sell and eventually were just phased out.

    Kohler doesnt have a minimum compression. 20psi is a decent difference though.
  9. tomo

    tomo LawnSite Senior Member
    Messages: 660

    hello, as i stated not familiar with that engine but , being that it is OHC[over head cam ] does it have mechanical tappet [valve ] clearance ,spec should be available .Tappet may be riding cam [leaves valve slightly open ] Check clearances with feeler guage as per manual either under cam side or valve side .

    Second time compression check as i mentioned then 4x squirts of oil in to cylinder and recheck comp .If comp comes up probaly 50 psi or more it is rings ,if it does not it is valves ,not sealing . Maybe due to as i mentioned above .
  10. ducky1

    ducky1 LawnSite Senior Member
    Messages: 252

    About the only thing left would be a head gasket maybe?

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