Carb icing on the Kohler 25HP

[Geoff]

Ahh winter is almost upon me.  We're dealing with near freezing temps & high humidity which is leading to a bunch of problems with the sawmill engine.  Carb icing is the number one problem, but the line coming up from the base of the crank (at the reed valves) which comes up just beside the choke on the carb was kicking back oil.

Had the valves replaced and am now trying to find an easy solution to the carb icing problem.  Kohler wants way too much money to put the icing kit on it.

Suggestions or experiences anyone??

Thanks,

Geoff

PS,  got a lead on a diesel genset and plan on sticking it out with the gas engine until I can switch to 3Phase electric.  Had electric before and LOVED it.

[smwwoody]

did you think of trying some type of heat gathering box around the exhaust then plumbing it into the air cleaner or around the carb?

[Kevin]

If you can use a tarp or something similar over the engine without making any contact the engine heat should keep things toasty.

[smwwoody]

yea maby even a cardboard box untill the motor warms up

[Tom]

Kohler !!!   I'm so disgusted and frustrated that I want to shoot my 20 horse kohler that is in a Craftsman lawn tractor/mower.  As soon as the maintenance contract was up with sears it started bending push rods. It would back fire before but nobody could find anything wrong with it. Now it backfires and the pushrods get bent. It has been to a Kohler dealer twice with no results and to a small engine repair several times with no results and I'm no mechanic. I'm definitely not going back to Sears and Kohler dealers are at a premium around here.  The next closest one is 50 miles away.

My admiration for Kohlers is fast disappearing.  If I hadn't spent $2500 for this confounded thing to begin with, I wouldn't feel so bad.   If my wife doesn't kill me first, the next mower will be some kind of professional model with a "real" engine.

No, Kohler won't talk to me and they won't talk to the small engine repair place.  It has to go to a Kohler dealer. $$$  grrrr

[Geoff]

Your idea of the shroud around the exhaust is exactly what Kohler wants to sell - for about $500 Cdn.  Frustrating when you've got logs to saw.

Tom,  you're correct about the distribution problems.  Getting parts are next to impossible.  I personally just love the $20 oil filters...come on!

[Kevin]

A fuel additive is something else that might help.

[Tom]

I added fuel to an engine one time and it ran longer. :P

[Kevin]

That`s a ...
 GROANER[/size][/glow]

[Bibbyman]

I had a similar problem with the 18 hp B&S that came on our 94 model mill.  It would round rough at temperatures under 50 and not run at all below 32.

B&S said to cut two holes in the shielding between the carburetor and muffler.  I did this with a conduit hole cutter.  

They also recommended removing the air tube from the shield to the air cleaner and placing tape over the hole in the air cleaner.  The air cleaner had two holes open on the backside that would draw air from near the muffler.

The above made little improvement.

My local small engine mechanic suggested the next hotter plug and using higher-octane gas.  That helped a little also.

I finally got desperate and duct taped a 12"x12" piece of cardboard over the shield in front of the engine about 2" in front of the fan shield.  This must have restricted the airflow enough to bring the engine temperature up.  It ran pretty good in cold weather after that.

We too have went to 3ph.  But we have a rotary phase converter.

P.S.  We have a 25hp Kohler Commander on our Blockbuster firewood processor and it has ran great right down to 0 f.

[ARKANSAWYER]

  "Wanda" is cold natured and if it is rainy and 35 degrees she will freeze up.  I have a piece of aluminum that is made to lay over the muffler and is kept in place by the wing nut of the air cleaner.  I helps keep heat in the area of the back of the carb.  Also when loading the next Iog I turn the engine off and let it heat soak while I load and level the log then fire up and saw.  If I think of it tomorrow I will mount it and take a photo to post.
ARKANSAWYER

 ps  oil filters are $7.50 and I can buy them in Yellville.

[Doeslyr]

Hook a 3/8 copper line to exhaust either by running it in end of muffler or braze it on. Route it to the carb icing spot and let er go. We had to do that to VW Dunebuggy. Ice was no good on the side of a pine needle hill. 

[SawyerTed]

Randomly dredging up 18 year old posts!  Wow!

[jmouton]

wow just noticed that sawyer ted

[JoshNZ]

Can you not just put a piece of hose over the air box intake and place the other end somewhere warm?

The only carb icing I've ever experienced is in Robbi helicopters and they have a shroud around the exhaust, and a lever you pull that diverts air from this shroud instead of from the side of the fuselage or wherever it is...

Procedure is only when you need it, as it robs a bit of power. One of startup checks is to use it while idling and observe a drop in RPM to confirm it's working, and you do see it it's pretty significant. Maybe interesting maybe not, but "when needed" is during low power manoeuvres descents/simulated engine failures where it'd be idling - i.e. when the throttle butterfly is closed. The ice is created when there is a large pressure differential across the butterfly, dropping pressure, dropping temperature, causing ice behind butterfly.

So perhaps a solution for you is to avoid idling too long. Leave your throttle half open if it's safe to do so.

Maybe/maybe not interesting again, the range in the manual that specifies to use it is -10C to something, let's say +12C (I forgot =/.) The idea being below -10C everything is frozen anyway, dry ice will go right through the carb, using carb heat could bring you back into that range where it's turned back into water vapour and could be a problem crossing low pressure Venturi/butterfly. So if it's super nuts cold, you're better sucking cold air.. Apparently...

Next model of robi is injected and is immune, so maybe that's a solution too lol. Presumably with no atomised cold air/fuel mix going past butterfly it's not a problem.

And that is my story... Sorry for the spiel xD

If your air box has a single intake port you could put a piece of vacuum cleaner hose or dust extractor hose etc over it, and poke the other end into your cooling shroud or close to cylinder fins, I guess it's air cooled? Or if not, ziptie it pointing closely to cylinder block or head/radiator/whatever so it has to draw air from across hot area.

[JoshNZ]

Agh. Should've noticed date lol. Sucked in

[donbj]

I read most of it too before catching the date thing. Still interesting read though