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Reviveing Kohler CH25 wont start

Discussion in 'Mechanic and Repair' started by weldondl, Jun 3, 2012.

  1. weldondl

    weldondl LawnSite Member
    Messages: 33

    Kohler CH25-68613 METALCRAFT (25 HP (18.61 kW) SN#3105017571 on a Scag Turf Tiger STT61A-25CH SN# 6711333 approx yr model 2001. Trying to get the engine to just fire off not expecting it to run more than a few seconds on starter fluid then maybe a little gas trickled into top of carb all fuel lines disconected cleaning out tank, any way engine should start and run, it did when i parked it approx 5 yrs ago. Im going to itemize so I dont get confused.

    1. Unplugged eng to mower connector, to eliminate all saftey sw.

    2. Removed breather to gain access to carb throat.

    3. sprayed minimal amount starting fluid directly into carb shorted between terminals on starter with flat blade screwdriver (redneck way) got some life ran for couple seconds ok great. Little noise little debrie blowing around motor.

    4. Re-peated step 3 more debrie and little pop ok

    5. Re-peated step 3 and nothing. RE-peated Re-peated still nothing

    6. ok do something else pulled a spark plug wire stuck screw driver in end and held close to metal bolt on engine once again rednecked the starter ah haa no spark. No spark no startey.

    7. Read some posts on here decided to gain access to flywheel and ignition parts did so with help from parts manual from a previous post. Lo and behold. This is, Texas, looked like a mud-dobber apartment complex after a earthquake inside the blower housing, hence the noise and debrie field. Cleaned all that out. Also decided to purchase new plugs (probably no need but did $4.41) gapped at .030. Installed new ones just because so when i do get spark(positive attitude) it be good to go.

    8. Decided to adjust MODULE, IGNITION (what the Book Calls it) i call it the coils 2-each should be gapped at .013 to flywhell magnet. (redneck tip no feeler gages i used a business card) Kids dont do this at home! I will go to town to buy feeler gages soon. Wiggled wires on terminals of coils all felt snug.

    9. Now remember the kill wire (white) is disconnected as is the mower plug, as is all fuel supply.

    10. Left cowling and fan off.

    11. Put plug wires back on newly installed plugs.

    12. Relying just on the engine ignition itself with starter fluid.

    13. From what I have gathered from reading many posts from here, it should start and run in this configuration.

    14. sprayed a little starter fluid and rednecked the starter and nothing, re-peated another time still no go.

    15. Pulled 1 spark plug wire inserted screw driver rednecked starter got a spark put wire back on re-peated on other spark plug got spark.

    16 Correct me if im wrong please, the MODULE, SPEED ADVANCE only comes into play when the engine is running True/False.

    17. The REGULATOR/RECTIFIER has nothing to do with ignition True/False

    18. So that brings me to the possibility that the mud-dobber condominium (rock hard mud houses)that was in the cowling when i first started the engine may have caused the shear pin between the crank and flywheel to shear throwing off the timeing.

    19. I will patiently await the time for those of you, who so generously give of there knowledge and time to make this the best forum on the net. Thanks in advance to all.
  2. piston slapper

    piston slapper LawnSite Platinum Member
    Messages: 4,329

    Plug the engine harness back in....leaving the white wire loose..
    With no power to the carb or SAM module...it ain't gonna run...
    Check your fuses...
    Posted via Mobile Device
  3. weldondl

    weldondl LawnSite Member
    Messages: 33

    So that would make my #16 a False. Module,Speed Advance(SAM) does play a role.

    As for power to the carb what does that do? Fuel solenoid valve maybe? Piston Slapper I am so afraid of the carb at this stage, sitting there for 5
    maybe 6 years that is why I am hitting it with the starter fluid get results, then i'll do the gas down the throat for little longer run. Then I'll drop a fuel line with new filter connected to fuel pump (which works) into say a 1/2 gallon of gas in a can see how it does. I gotta clean that tank some nasty stuff in it.

    After I posted earlier I had to re-think some stuff (mud-dobbers) so I went and examined the blower and housing it being all plastic man if something like a dobber nest was gonna shear a pin then it should have broken those fan vanes no damage there so I pretty much ruled out key way. Tomorrow I will get back on that connection after I make a run to town for some feeler gages and reset those ignition modules by the book, and probably pick up a remote start sw just in case i need it so i can quit red necking that starter. lol.

    P.S. 2 fuses both good but I will double check them. oh hell I'll buy new ones.

    Thanks for your time and your help.
  4. BigFish

    BigFish LawnSite Platinum Member
    Messages: 4,068

    The reg/rect. has nothing to do with the ign.
    The SAM module has EVERYTHING to do with the ign.!
    A business card is pretty much the standard for settin coil gaps. No need for fancy brass feeler gauges.

    Yeah the fuel solenoid needs 12V to allow fuel to reach the main jet. It's a good bet that after sitting for so long its a gummed up mess. Just unscrew it and test it with 12v, the plunger should retract. Or just snip the plunger/tip off and be done with it. ( most everybody does)
    Your prolly gonna have to pull the carb to clean it.
    Hit the Kohler website and download a shop manual.
  5. weldondl

    weldondl LawnSite Member
    Messages: 33

    Thanks BigFish. Yea Buddy I am running scared on the carb issue I know im gonna have to pull it and clean it. I think I had nightmares of that last night. First I gotta get all that dirt and grimm off the engine its a mess. I think maybe power wash it today. Just gotta keep the water out of carb/engine. I'll get back out on it sometime today.
  6. weldondl

    weldondl LawnSite Member
    Messages: 33

    Ok guys went ahead and power washed it at least now I can see the bolts that hold carb on and lots other things. lol After reading lots of posts on here concerning the Tigers plague with fuses and holders and since Big Fish mentioned the fuses I decided after the power wash I would just take a good look see. well I pulled the fuses looked good but not positive, My volt meter not handy so I stuck fuses back in pushed the seat button down and hit the starter sw hey the starter kicked in did it again good one more time nothing. pulled fuses didn't look so good. pulled the four bolts to gain access to controls and fuse holders took a close look could see problems of over heating. So off to town Got a slew of things 2 new fuse holders + 20 amp fuses it had 30A installed manual calls for 20A. Got oil,filter, to change soon after i have it running. new fuel filter, fuel line, still gotta clean the tank.

    Installed the fuse holders, then check with ohm meter to ground to insure no direct shorts to grnd all was good, installed fuses re-connected batt, hit the seat button starter works well no safety sw probleums re-connected white wire disconnected in first post, starter still working fuse holders was a Home Run out of the Park. Now the big test hit the carb with some start fluid walla we have ignition and short run. next poured a little gas into carb hooray ran a little longer. Thanks to BigFish and Piston Slapper for there direction. Next will pull carb and clean. Should I pick up a carb kit or just good cleaning any new gaskets. Luckilly im not relying on this equipement its just something was abandoned by family members lawn business and im resurrecting it to use on my 2 acres. I take my time.
  7. piston slapper

    piston slapper LawnSite Platinum Member
    Messages: 4,329

    You can do a quick clean on the carb by removing the screws and pulling the top off the carb....be very careful to note the position on the short brass tube with orings on each end....do not spray cleaner on the orings or top cover gasket...
    Posted via Mobile Device
  8. weldondl

    weldondl LawnSite Member
    Messages: 33

    Thanks piston slapper I got around to it late this evening pulled the fuel selonoid and the top off didn't look to bad in carb, worked the float up and down while I sprayed the needle valve, cleaned out the bowls, but the fuel selonoid was a little gummy so cleaned it well sprayed directly into hole it came out of. re-assymbled hooked up fuel lines a shot of starter fluid and waaalaaa. We now have a running engine and it sounds good, no smoking no knocking just need re-assemble cowling parts, change oil and filter, clean out fuel tank Then i'll take a look at hydraulics probably should do a filter and oil change there also. Thanks again for all the help.

    oops one other thing the shop this mower used to go to turned down the rpms on the motor i need to get it back up to speed at top end looks like they may have just moved the governor spring any thoughts. There are 4 holes looks like it may have been moved from the 3rd hole to the 2nd hole, 1st hole being the fartherest from the governor.

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