Is the Kohler Courage really that bad?

[chance123]

Mr Chance, each time we chat you emphasize that there are no heat problems in hot So Cal, but you mention failures that could be heat failures. For the benefit of the forum please tell us the brands you have and work on , and what kinds of failures you have, so there are some facts we can digest.

Heat failures can usually be seen by discoloration of the engine material. The old engines were made out of cast iron which dissipates heat "much" slower than today's alloys. In the 60's in my motorcycle days I had a Triumph 500 cc motorcycle with cast iron barrels and I remember running it in over 100 degree temps for more than a half hour standing still (0 MPH)! There was "no" air blowing across the cyl fins and no cooling fan. It never over heated. I also had an Ariel square 4 engine where there were 2 cylinders fore and 2 aft. "THOSE" 2 rear cylinders "would" overheat because of the lack of space between them. I also remember polishing the sand casting marks off of the fins on an aluminum head only to notice an increase in head temp. (I reduced the surface area) You must remember that if you measure the surface area of the top and bottom of "each" cooling fin on these engines we work on today, that adds up to a "lot" of surface area. On top of that, today's aluminum dissipates heat almost instantly with the cooling fans we have on the flywheels.
Now, with regard to "this" Kohler engine, with all the problems that are happening, if they "are" heat related, then there is a design flaw, because the older Kohler engines do "not" have those problems working under the same working conditions.
I work on B&S, Kohler, Wisconson, (and Robin), Suzuki, Tecumseh (RIP), Clinton (not many still running) Kawasaki, and never seen overheating problems even with debris clogging the fins. Yes they would get hot, but not overheat.

 

[motoman]

Mr Chance, Thanks for naming the brands you work on. Please know that this is only discussion and not some kind of contest. You seem to have the great advantage of doing repair as a living. So when I keep asking questions it is not personal.

Discoloration of steel can be quantified by temperature in degrees. If anyone is interested I will post the well know temper color charts. These colors can interpret heat on steel like catalytic mufflers, steel cylinder bores, and exhaust pipes. If you know of discoloration charts on aluminum please tell us as I believe that many of the problems on Aluminum aircooled mower engines are overheated engine heads. Why do I believe this. Certainly not from vast experience with tractors or lawnmowers, rather from being a moto nut and reading a lot.

If a valve breaks what exactly has happened? If valve seats loosen and pushrods are thrown or bent what exactly has happened. If a valve guide is "pushed" up into the head or properly torqued head bolts loosen, what has happened?

I notice that on my test mule, the INTEK 24, there is no oil feed to the exhaust guide, only a vapor for lubrication. So that guide is relying entirely on conduction and air to cool it. Some engine gurus have corrected overheating heads by finally piping oil over guides. Mr chance why don't you take some temps as you service these machines. I realize you are a businessman and not a hobbyist. Does't it bother you that you do not think of some reason for the failures you see? The word "design" must be defined for us. Again , thanks for participating in this dicussion and I understand if you think this is "much ado about nothing." :wink:

 

[chance123]

Mr Chance, Thanks for naming the brands you work on. Please know that this is only discussion and not some kind of contest. You seem to have the great advantage of doing repair as a living. So when I keep asking questions it is not personal.

Discoloration of steel can be quantified by temperature in degrees. If anyone is interested I will post the well know temper color charts. These colors can interpret heat on steel like catalytic mufflers, steel cylinder bores, and exhaust pipes. If you know of discoloration charts on aluminum please tell us as I believe that many of the problems on Aluminum aircooled mower engines are overheated engine heads. Why do I believe this. Certainly not from vast experience with tractors or lawnmowers, rather from being a moto nut and reading a lot.

If a valve breaks what exactly has happened? If valve seats loosen and pushrods are thrown or bent what exactly has happened. If a valve guide is "pushed" up into the head or properly torqued head bolts loosen, what has happened?

I notice that on my test mule, the INTEK 24, there is no oil feed to the exhaust guide, only a vapor for lubrication. So that guide is relying entirely on conduction and air to cool it. Some engine gurus have corrected overheating heads by finally piping oil over guides. Mr chance why don't you take some temps as you service these machines. I realize you are a businessman and not a hobbyist. Does't it bother you that you do not think of some reason for the failures you see? The word "design" must be defined for us. Again , thanks for participating in this dicussion and I understand if you think this is "much ado about nothing." :wink:

No offence taken. It would be hard to take temp measurements here in the shop. That would best be done in the heat of the day under heavy loads out in the field.
Sure it bothers me and I "do" have reasons for the repeated failures with only this "one" engine! I see it over and over here in my shop and on this board too in other parts of the country. I have spoken with Kohler about this and they said to me "in 2k13 we will be clamping down with our QC on the Courage engines. Over heating? Only on this one engine? I believe it is more than that. When the last valve broke, the machine was running in the mid morning when it was only about 70 degrees and overcast.
I was not making this out to be a contest. I am merely sharing my experiences which goes back to 1960 and never seen an overheating problem with these air cooled engines. Water pumpers? Yes! The Kawais with the FD 750D have their problems which result in warped heads and other problems that would "never" happen with air cooling. When bolts come loose, many times it is because the aluminum pieces and the steel bolts expand (with heat) at a different ratio and is why it is critical to torque in sequence to spec. I have seen loose (finger tight) case bolts on a brand new in the box Courage engine. Kohler "HAS" to be feeling the heat over this.
BTW, Hot steel turns blue/purple and aluminum turns black

 

[motoman]

Mr chance , some random thoughts...your stationary Triumph had oil jets trained on the valve guides . Then the oil was circulated thru a remote oil tank which took a while to heat up.

A site I quoted in the K thermocouple thread (gasket manufacturer) stated that its alleged gasket failures were due to softened aluminum heads which "gave" under the head torqueing sequence. The heads had been overheated

My Intek guide which pushed could not be bought. Why ? Briggs Stratton knows that oversized guides will also push due to weaken aluminum (overheat). I had to buy new heads complete.

I recently bought "reman" brake calipers from Autozone. They would not accept the required threaded hardware to proper torque-the fasteners pulled the threads right out. Reason: the prior owner had overheated the aluminum caliper and Autozone's supplier did not perform hardness test on incoming cores.

Known "tempering" colors. These are used by blacksmiths who are quenching to desired toughness and by home hobbyist who are retempering screwdriver tips after regrind. "Fingerprints" for carbon steel temperatures . Browns 420-480F, Yellows 490-520 F, Purples 530-550F, Blues 560-610F. I see these colors on my headers, catalytic converter, overheated grinder workpieces. Aluminum ,like steel comes in 57 Heinz varieties of alloy. I only know the trick body guys use who work aluminum. If it work hardens from forming and must be reformed they go with a sooty oxyacetylene coating and then go 50-50 until the black burns off which indicates the Al is annealed-temp unknown.

Corvair and VW engines are notorious for loosened valve seats due to overheated heads.

Don't know where all this is going , but others may feel like chiming in.
:biggrin:

 

[chance123]

Mr chance , some random thoughts...your stationary Triumph had oil jets trained on the valve guides . Then the oil was circulated thru a remote oil tank which took a while to heat up.

A site I quoted in the K thermocouple thread (gasket manufacturer) stated that its alleged gasket failures were due to softened aluminum heads which "gave" under the head torqueing sequence. The heads had been overheated

My Intek guide which pushed could not be bought. Why ? Briggs Stratton knows that oversized guides will also push due to weaken aluminum (overheat). I had to buy new heads complete.

I recently bought "reman" brake calipers from Autozone. They would not accept the required threaded hardware to proper torque-the fasteners pulled the threads right out. Reason: the prior owner had overheated the aluminum caliper and Autozone's supplier did not perform hardness test on incoming cores.

Known "tempering" colors. These are used by blacksmiths who are quenching to desired toughness and by home hobbyist who are retempering screwdriver tips after regrind. "Fingerprints" for carbon steel temperatures . Browns 420-480F, Yellows 490-520 F, Purples 530-550F, Blues 560-610F. I see these colors on my headers, catalytic converter, overheated grinder workpieces. Aluminum ,like steel comes in 57 Heinz varieties of alloy. I only know the trick body guys use who work aluminum. If it work hardens from forming and must be reformed they go with a sooty oxyacetylene coating and then go 50-50 until the black burns off which indicates the Al is annealed-temp unknown.

Corvair and VW engines are notorious for loosened valve seats due to overheated heads.

Don't know where all this is going , but others may feel like chiming in.
:biggrin:

I don't know where this is going either LOL makes for interesting talk, but with the Mazda Rotary engines, it is "normal" for the exhaust pipes to glow red hot.

 

[metz12]

Mine isnt bad. Actually its pretty nice. I dont mow with my craftsman though i just use it as a tractor. i dont think that would have anything to do with it though.

 

[kevicarlson]

My kohler experience -

Bought a ryobi riding mower with courage 19hp sv590-012 engine. Ran it for two seasons on better than an acre and some misc hauling of small trailer around with dirt and wood. It's a 2006 that i bought used from a shade tree guy in in early 2011.
It has run great with little maintenance as I "rookie" my way through owning first riding mower. Then it started spitting oil out breather. Replaced head gasket, valve gasket and valve adjustment andi t has resolved and is running well.
Considering the maintenance neglect on this motor I have either lucked out or not run it hard enough to damage it worse? in my two years with it I would suggest I have overr 100 hrs per year on it for 200+ by me and no telling what it had before I got it.
It's hard to find much discussion on the Internet on this engine or parts for that matter - maybe the extreme nature of the noted failures has people in an unwarranted frenzy about its reliability? Just sayin.

 

[possum]

The frustration is a perfectly good tractor that still looks and runs like new with a destroyed engine along with a replacement cost that prevents the re engine of the tractor. There has to be many that do well as they are on OPE all over the world.

 

[edd]

have a 23 horse courage on a toro timecutter.......roughly 500 hrs and not a problem yet.......ran a courage on a craftsman rider for 3 years and it still runs good

 

[066]

In the past 5 or 6 years i've seen 4 or 5 cracked courage blocks, all cracked on the exhaust side & underneath & all on rear engine zero-turn machines, i managed to get a warranty claim for 1 that had 120 hrs on it & was well out of it's warranty period, i couldn't believe the claim was approved, our Kohler agent in this country seems to be switched on & they went to Kohler in Italy who approved the claim.
We have also sold many Husqvarna front engine mowers with the courage engine & have never had a cracked block.