Kohler K-series engine temperature

Troubleshooting, rebuilding, repairing Kohler engines.
User avatar
DavidBarkey Canada
Posts: 3108
Joined: Sat Mar 06, 2021 10:35 am
Location: Waverley On.
Has thanked: 17080 times
Been thanked: 10414 times

Re: Multi-function engine monitor gauge

Post by DavidBarkey »

So looking for ."what is operating temp air cooled engine " here is a few results .

Quote I recently installed an oil pressure gauge and a temp gauge on my 20hp Kohler engine (Craftsman tractor). I glued the temp sendor against the block (don't know how accurate that is, but it gives me a baseline). After running a while in 100 degree heat, I'll see 240F on the gauge. When I shoot the oil filter with my temp gun, I see 240-245F. Oil pressures run 35-40lbs. BTW, I'm running 15w40 Delo and an ST8 Supertech filter, (yes it't big and it fits!)

Quote : My John Deere runs at 200F in the crankcase with a 13 HP Tecumseh single cylinder using 0W30 GC. Outside air temp was 102F. This was during and after mowing 1/2 acre. I would stop in the middle of mowing and raise the hood and take the reading immediately with my IR temp gun.

Quote :Oil from the sump just after 2+- hour run is 250°on our Kohler Courage 25HP on Gravely ZTR. I used Rotella 10w-30 CJ4 since new. No oil consumption. I just switch over to Rotella T5 10w-30.

Quote :Normal for aircooled engines is generally below 260F. Ideal is about 220, that way it boils off moisture but it not too thin due to excess temperature. I generally use Mobil 1 15-50 for my air cooled engines here in Florida. I lost 2 Honda powered water pumps using conventional oils. The reason was, as you noticed, excess oil temperature. The switch to M1 15-50 did nothing to address the excess heat. However, the oil is able to handle the heat and remains in grade while hot. For engines that don't run as hot, I use M1 5-40 Turbo Diesel Truck. It is ideal for air cooled requirements, with plenty of ZDDP. As I keep saying, generators here in S. FL fail with alarming regularity using 5-30 oils. And, it's ABSOLUTELY an oil related issue. Thin, modern auto oils are not engineered to run at such high temps and the results are obvious. Put another way, air cooled engines with plain connecting rod bearings require a certain viscosity. Do you think 5-30 dino oil provides this at 290 degrees F?

Quote :OK Guys: I just spoke with a real, live Kohler Engine Tech and he informed me that 280-290 is "normal" for the CV730S 25 HP engine and will see temps up to 310! Guess I will let er rip and stop the worrying.

I know from my days in auto repair and racing that liquid cooled engines the oil runs hotter than he oil . That is why a lot of HD and performance engines run "oil coolers" . You are seeing them on air cooled small engines now as well to keep the oil from breaking down . That being said , as stated above in one quote , there is a lot to be said for not running hot enough or running long enough to dry out condensation . I personally have had my farmers JD gaters blow white smoke in the spring like it blew a head gasket on a liquid cool engine and it is air cooled . Check the oil and it is milky and over full due to all the condensation built up in it . Winter time they were doing short runs cleaning stalls and not letting in run long enough . Now water boils at 212F / 100C . So based on that , ideal oil temp in my mind would be between 225F and 250 F / 107C and 121C.

:hm:
Dave
Mad Tractor Builder
User avatar
propane1 Canada
Posts: 2428
Joined: Thu Dec 23, 2021 11:32 am
Location: PEI, Canada
Has thanked: 5741 times
Been thanked: 8671 times

Re: Multi-function engine monitor gauge

Post by propane1 »

I was looking for info on engine temperatures too. Didn’t find much thou. One I did find said 180 to 200 F. But not sure where that was measured at.
So if I think of it the next time I cut grass with the 224, I will test a few spots with my temperature tester. I don’t notice the 224 engine to be very hot, so I’m curious now. The one engine I had that was late in timing had the steel engine bonnet so hot you could not touch it. You could feel the radiant heat from the tractor when standing beside it. The other time was with my John Deere tractor. Was not roaring hot, but melted the decal a bit on the fibreglass hood. It lacked power and exhaust was louder and more pressure out the pipe than normal. Caused by late timing.


Noel
User avatar
Eugen Canada
Posts: 5141
Joined: Wed Mar 03, 2021 2:52 pm
Location: Port Mcnicoll, Ontario
Has thanked: 11934 times
Been thanked: 16195 times
Contact:

Re: Multi-function engine monitor gauge

Post by Eugen »

oh, Noel, I guess I didn't pay enough attention and I thought you're measuring the engine oil!! :rofl:

@DavidBarkey interesting data. I now recall reading stuff about air cooled engines head operating temperatures, but didn't remember the numbers, thank you for posting that here. Being an air cooled engine, there's probably a whole theory about where to actually measure the temperature.
Case 224, 444, 644, 680E
Kubota B26 :blush:
User avatar
Eugen Canada
Posts: 5141
Joined: Wed Mar 03, 2021 2:52 pm
Location: Port Mcnicoll, Ontario
Has thanked: 11934 times
Been thanked: 16195 times
Contact:

Re: Multi-function engine monitor gauge

Post by Eugen »

Found this very detailed info about single cylinder k-series and measuring engine temperature(s):

"Hi, A pyrometer with the thermocouple under the spark plug would provide more information than an oil temp gauge. When we do the temp testing of our kits for Kohler sign off, we have thermocouples under the spark plugs, 4 thermocouples at 12, 3, 6 and 9 o-clock 1/2 inch back and 1/2 inch in from the blower intake. 1 thermocouple in the crankcase near the oil pump pickup for oil temp. They don't use the crankcase holes because a large portion of an air cooled engines cooling is transfer of heat though the crank case walls. Hence the ribs in the new castings and bases on the new generation engines. When you use a drain hole for the oil sensor the sump reduces the oil temp. Maybe less so on a dipper engine, but this is why we use oil pump pick up temp. Then a thermocouple in the float bowl of the carb and 1 in the venturi. 2 on the bottom of the hood. The muffler pipes have a tap welded into a straight portion of the pipe as close to 1 inch from the head as possible. These are connected to 2 manometers to monitor back pressure at each cylinder. If back pressure spec is exceeded it throws the emissions out of spec. This qualifies for a 34500.00 fine for every one you sell, if the EPA finds out about it. When have our mufflers made, the first 3 we back pressure test with the largest engine we will use and run for 30 minutes wide open full load on a dyno. When we got our first 3 samples for our JD 318 kits, one of the 3 was out on 1 cyl. we cut it open and found the problem. Contacting our mfr, we made a correction so it won't happen in future production. This is a 3 hour temp run on the dyno in a "hot room". A rep for Kohler comes in and takes the readings. If we pass it we can sell our kits any place in the world and not have to worry that an engine failure can result in a refused warranty with the engine mfr saying contact the people that built the kit. They have heat recirculation or other cooling problems. Now that you asked what time was and I got carried away and tried to tell you how to build a watch. Sorry. To sum it up, head temp would provide more valuable info."

sounds good! :rofl:
Case 224, 444, 644, 680E
Kubota B26 :blush:
User avatar
Eugen Canada
Posts: 5141
Joined: Wed Mar 03, 2021 2:52 pm
Location: Port Mcnicoll, Ontario
Has thanked: 11934 times
Been thanked: 16195 times
Contact:

Re: Multi-function engine monitor gauge

Post by Eugen »

Given all this info about temperature of air cooled engines, it seems to me that a monitoring the temperature via gauge that goes under the spark plug would be the most informative.
Screen Shot 2022-07-06 at 11.58.46.png
Case 224, 444, 644, 680E
Kubota B26 :blush:
User avatar
DavidBarkey Canada
Posts: 3108
Joined: Sat Mar 06, 2021 10:35 am
Location: Waverley On.
Has thanked: 17080 times
Been thanked: 10414 times

Re: Multi-function engine monitor gauge

Post by DavidBarkey »

Agreed , the head temp is of concern . And would be good to know and be able to monitor . A base line would be helpfull . Me I am more concerned with oil temp . Too low and you will not burn off condensation contaminating oil and causing damage . Too high oil will fail and so will parts . Again a base line would help. But we know the boiling point of water . If the head temp is to high for what ever reason the piston will be too and so will the oil . Now that being said , being able to monitor head temp will give you an early warning before oil gets too high . So Both have there importance . My new tractor , the snow blower project will have an array of analog gauges so I can look at all at same time . Besides it looks cool and is a good way to teach the young man . Engine oil pressure and temp , RPM, Volts, Hydra pressure and temp. CO for safety . Fuel gauge for convenience. That head temp gauge would be nice for diag purposes.
Dave
Mad Tractor Builder
User avatar
Eugen Canada
Posts: 5141
Joined: Wed Mar 03, 2021 2:52 pm
Location: Port Mcnicoll, Ontario
Has thanked: 11934 times
Been thanked: 16195 times
Contact:

Re: Multi-function engine monitor gauge

Post by Eugen »

Propane57 wrote: Wed Jul 06, 2022 4:54 am Did you check your timing yet on that engine ? :45: :giggle: :giggle:

Noel
Cannot find the S mark on the flywheel :43:
Case 224, 444, 644, 680E
Kubota B26 :blush:
User avatar
propane1 Canada
Posts: 2428
Joined: Thu Dec 23, 2021 11:32 am
Location: PEI, Canada
Has thanked: 5741 times
Been thanked: 8671 times

Re: Multi-function engine monitor gauge

Post by propane1 »

It’s there. Also a T.

Noel
User avatar
Eugen Canada
Posts: 5141
Joined: Wed Mar 03, 2021 2:52 pm
Location: Port Mcnicoll, Ontario
Has thanked: 11934 times
Been thanked: 16195 times
Contact:

Kohler K-series engine temperature

Post by Eugen »

Propane57 wrote: Thu Jul 07, 2022 4:42 am It’s there. Also a T.

Noel
Thank you Noel, I'm sure it's there, just could not see it through the opening in the cover. The flywheel is pretty rusty on that area so I might have to take off the cover completely and cleanup the flywheel hoping to uncover the marks.
Case 224, 444, 644, 680E
Kubota B26 :blush:
User avatar
Eugen Canada
Posts: 5141
Joined: Wed Mar 03, 2021 2:52 pm
Location: Port Mcnicoll, Ontario
Has thanked: 11934 times
Been thanked: 16195 times
Contact:

Re: Kohler K-series engine temperature

Post by Eugen »

I have a 444 that's running really well and I use at the moment just for mowing, that never overheats. I will check the temperature on it with the IR thermometer on the head, right around the spark plug so we can use that as a base line. There's a digital thermometer with a k-type thermocouple hidden somewhere among all my junk, when I find it I'll install the thermocouple right next to the spark plug and get some more precise readings.
Case 224, 444, 644, 680E
Kubota B26 :blush:
Post Reply