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Discussion Starter · #1 ·
Hello,

I have a kohler CV15S on a craftsman mower that is giving me issues.

symptoms:

It surges and puffs black smoke out the exhaust and only levels out when i shut the fuel off right before it runs out if gas.
Fuel in oil
compression is at 60PSI


Configuration of motor:

gravity fed fuel with no ignition module. Just a coil and a plug. Right now i have the shut down lead off the coil.

attempts to repair:

New Plug
brand new carb
oiled cylinder and re checked compression - still 60PSI and holds there- turned the motor over 5 cycles to try to get accurate reading.
changed oil - no change
New Coil - set clearance with business card - no change.
the valves seem to be operating correctly (no valve noise) - use 10w-30 oil
governor spring still attached
took off air cleaner - still getting too much fuel

can anyone help me out, i am completely out of ideas....
 

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sounds as if there is something stuck in float valve or a hole in float alowing fuel to enter decreasing bouyence and not letting the valve close properly. check,repair, rebuild or replace carburator.
 

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If you had same problem [black smoke and flooding], with both the old and brand new carburetor, and sure seems like a carb problem....It's possible you have more 'crap' in fuel line, and it's preventing both needles from fully seating....Remove carb, blow out back thru fuel inlet, and replace and flush fuel lines...sometimes tiny "slivers" of flaking fuel lines find their way to the needle...add new filter too...!
 

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:ditto: I had a similar problem and it finally leveled itself out once I replaced the carb. But soon after found I was getting little pieces of rubber from the inside of the fuel cap I decided to replace my fuel line and completely drain the fuel tank. While I was in the process I decided it was also a perfect time to install a fuel cut-off switch. All in all it's hard to narrow it down sometimes until you try process of elimination such as yourself. Even then it can be kind of a head scratcher. :dunno:

Hopefully it will help trying this. Be sure and let us know how it turns out... :help:
 

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Discussion Starter · #5 ·
Fuel lines are clear, fuel tank was cleaned, new filter is on, another new carb(by some miracle the company i bought the first new one from took it back). same problem.

60 PSI sounds low, even with an ACR. Could it be that the intake valve is not opening all the way, or not enough? Or that the engine is not able to compress the mixture completely and its leaving unburnt fuel go out the exhaust? I oiled the rings and the compression value did not change so does that mean the leak is at the valves or head?
 

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I changed the head gasket on one of these and the compression was at 70 even with the blown head gasket, severely blown in fact. 60 is a little too low
 

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If 60-70 psi is way too low compression with CR "ON"...would that not translate to roughly over 100# when CR stops...Confusing [to me] is just what reading do our members consider to be needed for normal running ?
 

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Discussion Starter · #11 ·
I have not checked valve clearance. Are you referring to the lifter clearance or the clearance from the valve to the seat? I have not pulled the head on this motor yet. I am sure it was running rich when i got it because the spark plug was black. Perhaps the valves are carboned up?
 

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I'm talking about the clearance between the rocker arm and the valve stem. This is important on OHV engines.

If 60-70 psi is way too low compression with CR "ON"...would that not translate to roughly over 100# when CR stops...Confusing [to me] is just what reading do our members consider to be needed for normal running ?
60 is low even with ACR.
 

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I'm no expert, but I've never seen 60 psi [while on CR] be soooo low that it prevents engine from running...But, what do I know...Heck, I'm still trying to figure out how YOU have adjusted the valve lash on these hydr lifter Kohler engines..??
 

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Sometimes the lifters get clogged or worn, putting the valves out of spec. They may be self-adjusting, but they're sure not foolproof. :rolleyes:
 
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