Kohler K341 (16hp)

Jack345

Member
My K341 smokes right after starting when cold. I never see it smoke when warm and running, could this be worn valves/guides? I'm thinking when choke is used in cold starting its pulling oil past the valves. Are there stem seals on the valves?

I have a Gravely with a K301 that never smokes or uses oil it has about 2000 hrs on it, the K341 looks to be a low hour engine but this smoking on start up has me wondering what is going one. Any help would be great. Thanks
 
IMHO, valves in a "flathead" engine are not likely to be the source of lots of smoke on startup, as there"s not much oil in the valve stem area in the first place, and it has to travel straight UP to get past the stem and into the intake port, vs. a "valve-in-head" engine where oil is drizzled over the valvespring/valvestem area, and simply has to move DOWNWARD to get to the intake port.
 
Sorry but I have to disagree.

In Section 11, Page 6 of the Kohler Service Manual, it states: "If a valve guide is worn beyond specifications, it will not guide the valve in a straight line. This may result in a burnt valve face or seat, loss of compression, and excessive oil consumption."

There is plenty of oil available to be sucked past worn guides because the crankcase breather also serves as the cover for the valve stem/springs. You must remove this cover in order to set the valve lash. During operation of the engine, the entire crankcase area is awash with an oil mist thanks to the dipper on the end of the connecting rod splashing the liquid oil.

The up and down movement of the piston creates positive and negative pressures inside the crankcase and the breather assembly addresses those pressures to neutralize them. A faulty breather will allow engine oil to drool out of the vent.

It does not take a lot of oil in the combustion chamber to create a bluish tinge in the exhaust gasses.
Kohler Manual
 
I happen to agree with Tom Arnold here but there is no reason to guess. Start it up, wait for smoke then shut off. Remove the muffler and carburetor and look. If enough oil is passing the guides to cause smoke then the valve stems will be wet with it. Enough oil being pumped from any source will result is wet exhaust port so be careful how you analyze. Only takes another 15 minutes to remove the head. Look at the piston top, if there is a clean ring around the outer edge the oil is coming past the rings. Also look over the crankcase breather a reed valve, problems there can cause oil usage also. As said, Kohler sure has a nice manual and you can download it for free from their web site.
 
GOOD points, Tom!

Breather problems are certainly a possibility, or simply a worn bore/rings.

As we know, with a properly functioning breather and rings that seal well, the engine will operated with NEGATIVE pressure in the crankcase, making it tough for the oil to defy gravity and move UPWARD.

(Crankcase negative pressure/manometer test is covered in 4.2 and 4.3 of the manual... 5" to 10" water column.)

While it's certainly POSSIBLE the guides are at fault, oil migration past worn valve guides comes up #5 out of the list of 5 causes of oil burning in the official Kohler manual.

Start at the top of the list/most likely cause and work from there. (Occam's razor)
 
Thanks for all the info. A bit more history on the engine last spring when I got the tractor I did remove head to clean valves,piston & head.The engine showed no ring grove & factory machine marks were clear, the sparkplug had factory paint on it and was not too bad of condition.The engine had a bad flywheel.(pto shaft came off the mower deck & slapped the flywheel removing the fins) The Ariens S 16H sat for years in covered area.
 
Picture the should have been on last message.Tool carrier works off rear hydraulics & will lift & carry 300-400lbs.Dogs love it.
a134462.jpg
 

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