Engine temps Kohler K Series

[sgtsampay 117]

So what is the correct temps one should be seeing on a kohler K series engine when using an infared gauge? What place is the best place to check on the engine? Spark plug? If so, what is the temp range it should be at? Should I bother with a spark plug temp sensor and if so what would I be looking for? I have a K341 for reference. Thank all for your time. 

[Snoopy11 5,714]

5 minutes ago, sgtsampay said:

So what is the correct temps one should be seeing on a kohler K series engine when using an infared gauge? What place is the best place to check on the engine? Spark plug? If so, what is the temp range it should be at? Should I bother with a spark plug temp sensor and if so what would I be looking for? I have a K341 for reference. Thank all for your time. 

Well, I think the first variable is outside ambient temperature. Aircooled engines usually run below 250-260 degrees... anything more than that needs more fuel in my opinion.

 

Also, just keep in mind the temperature is not consistent across the cylinder head as the cool air/fuel mix enters at the intake valve, and the mix is still burning as it exits the exhaust valve right beside the intake valve.  You could pull 250 over the intake valve, and 300+ over the exhaust valve.

 

If you wanted my opinion, the best temperature advice that you will get on one of these small engines is oil temperature.

 

Don

[sgtsampay 117]

5 minutes ago, Snoopy11 said:

Well, I think the first variable is outside ambient temperature. Aircooled engines usually run below 250-260 degrees... anything more than that needs more fuel in my opinion.

 

Also, just keep in mind the temperature is not consistent across the cylinder head as the cool air/fuel mix enters at the intake valve, and the mix is still burning as it exits the exhaust valve right beside the intake valve.  You could pull 250 over the intake valve, and 300+ over the exhaust valve.

 

If you wanted my opinion, the best temperature advice that you will get on one of these small engines is oil temperature.

 

Don

How would you get the oil temp on one of these?

[Snoopy11 5,714]

4 minutes ago, sgtsampay said:

How would you get the oil temp on one of these?

Drill and tap the block. Preferably the side cover. Buy a gauge like this with a mechanical sender:

 

 

Don

Edited January 28, 2022 by Snoopy11

[Snoopy11 5,714]

7 minutes ago, sgtsampay said:

How would you get the oil temp on one of these?

You could also drill and tap the block and use a Harley Davidson type gauge. OR replace your oil dipstick/fill cap altogether with it...

 

 

Don

 

 

[Snoopy11 5,714]

14 minutes ago, sgtsampay said:

How would you get the oil temp on one of these?

 

Somebody hit the rock-and-roll for me, won't you?

 

They also have... digital...

 

 

Don

 

 

[Snoopy11 5,714]

Imma' see if any other guys here might have some ideas/feedback...

 

@squonk @Handy Don  @pacer @kpinnc Among many others...

 

 

 

Don

 

 

[kpinnc 12,175]

45 minutes ago, Snoopy11 said:

Imma' see if any other guys here might have some ideas/feedback...

 

@squonk @Handy Don  @pacer @kpinnc Among many others...

 

I have to say, I've never checked my Kohlers. So long as they are clean and full of oil. I regulary check the carb adjustment too.

[Snoopy11 5,714]

Just now, kpinnc said:

carb adjustment

Yeah... I think... carb adjustments are more about the sound of the motor... moreso than heat. That is, unless your exhaust is glowing... then you should be... a bit concerned.

 

Don

[sgtsampay 117]

2 minutes ago, kpinnc said:

 

I have to say, I've never checked my Kohlers. So long as they are clean and full of oil. I regulary check the carb adjustment too.

what do you do for this check?

 

As for as the oil temp guages, it seems a bit over kill to drill and tap the block.. 

[Snoopy11 5,714]

1 minute ago, sgtsampay said:

it seems a bit over kill to drill and tap the block

I would agree... especially if it isn't something that you are comfortable doing.

 

I have been told that you 'could' take an infrared reading of the oil itself (and oil filter if applicable)... but that is not something that I have personally done on a Kohler. I did it once on a briggs v-twin... and got a false reading...

 

Don

[kpinnc 12,175]

2 minutes ago, sgtsampay said:

what do you do for this check?

 

With them being splash lube, there isn't much you can do to affect it if all other requirements (fin cleanliness, oil level, correct fuel mix) are where they should be. If the engine has a tendency to run hot, you'll see it on the dipstick. Most oil turns dark brown (if changed regularly) when exposed to high temps.

[Snoopy11 5,714]

Just now, kpinnc said:

 

With them being splash lube, there isn't much you can do to affect it if all other requirements (fin cleanliness, oil level, correct fuel mix) are where they should be. If the engine has a tendency to run hot, you'll see it on the dipstick. Most oil turns dark brown (if changed regularly) when exposed to high temps.

You can play with carb adjustments... but if it isn't hunting/surging/backfiring/popping/glowing/valve pinging... or any of those things... it should be fine.

 

Don

[kpinnc 12,175]

The only other thing I've seen that made a K run hot was points way out of adjustment. That was a K181, and it ran like it was under load all the time.

[Snoopy11 5,714]

1 minute ago, kpinnc said:

The only other thing I've seen that made a K run hot was points way out of adjustment. That was a K181, and it ran like it was under load all the time.

Valves out of adjustment would be another.

 

Don

[kpinnc 12,175]

Long story short: if you maintain your K series or Magnum properly, running hot doesn't usually happen.

 

Of course you can wire in a temp switch to kill the engine if you wanted for either ignition type. I just don't know what the max temp is...

[ebinmaine 67,766]

5 hours ago, sgtsampay said:

what would I be looking for?

What in particular or why is it that you think you need to check the temp?

Just precaution?

Some issue?

 

[sgtsampay 117]

23 minutes ago, ebinmaine said:

What in particular or why is it that you think you need to check the temp?

Just precaution?

Some issue?

 

well. Its mainly to check to see if my carb tuning is running correctly, along with the valves and such. Ok, so during the summer i was running the tractor and I used my infrared temp gun on the engines to see how hot the thing would get. The head was around 300 something but the little pipe from the exhaust port to the muffler was around 500 or so. But the engine run well and its really only that little area that is really hotter than 300 something. Again I don't know if I did something wrong was it was a fluke. I also really enjoy this tractor and don't want anything to happen to it. It has plenty of power, runs very well, hydro is strong, etc. So basically I'm concern I'm missing something and the tractor will break. LOL. 

 

[Snoopy11 5,714]

17 hours ago, sgtsampay said:

well. Its mainly to check to see if my carb tuning is running correctly, along with the valves and such. Ok, so during the summer i was running the tractor and I used my infrared temp gun on the engines to see how hot the thing would get. The head was around 300 something but the little pipe from the exhaust port to the muffler was around 500 or so. But the engine run well and its really only that little area that is really hotter than 300 something. Again I don't know if I did something wrong was it was a fluke. I also really enjoy this tractor and don't want anything to happen to it. It has plenty of power, runs very well, hydro is strong, etc. So basically I'm concern I'm missing something and the tractor will break. LOL. 

 

Absolutely! I think you could play with carb adjustments. As long as the motor does not stutter, pop, or backfire, you can add as much fuel as it will take.

 

This is what we do when we change jets to tune performance engines. No exact science or temperature... just sound. Play with it until it sounds wicked... then leave it the hell alone.

 

You will know once you get to a point where you have too much fuel... or not enough.

 

Not enough fuel will also cause it to hunt and surge a bit.

 

Don

[RED-Z06 2,221]

I put a Head temp gauge on my K241, also monitors battery voltage.  Ambient temp does affect cht, not alot but some.

 

The 42" deck put a good load on the 10hp engine and i see a top head temp mid summer mowing grass of 266⁰F.  Mowing mid winter, head temps sit around 242⁰ doing the same work.  Plug comes out clean after working.  You really arent in any real danger until you start to creep up on 320⁰...and that's head temp, oil temp will run much lower.  Oil temps on small engines are pretty pointless, the oil temp is the slowest temp to react to changes, cht, egt are pretty instant..but oil, you might see a 150+ degree gauge start to move after 20 minutes, and if you get into a short high load situation..the oil temp may not respond accordingly.

 

Oil temp is more important in applications like commercial Zero Turns or larger tractors, performance cars...where you may go long periods of load and oil overheating is a possibility.

[Greentored 3,217]

I have an oil temp gauge on Hoss (in pic to the left). Standard mechanical engine temp gauge with an adapter, threaded right into the rear oil drain hole in the pan.

Thats a 14hp Kohler with a chevy LS intake valve cut down to 1.65, tons of porting and relieving, mild custom grind cam, and 9.3:1 compression, governed at 3800.

The hottest Ive ever seen the oil was about 160 degrees, and that was on a 85 degree day, yanking a plow through the dirt.

My main concern was cooking oil vs cylinder head temps, but have learned that oil temp on a splasher isnt going to tell us much. Theres no doubt in my mind the oil temp at the big end of the rod is a lot more than 150 degrees.

We'd see as much as 475-500 degrees head temp back in the briggs kart days without issues, and also think about the Harleys with anywhere from 50-100+hp and NO fans at all to help cool em.

[RED-Z06 2,221]

45 minutes ago, Greentored said:

I have an oil temp gauge on Hoss (in pic to the left). Standard mechanical engine temp gauge with an adapter, threaded right into the rear oil drain hole in the pan.

Thats a 14hp Kohler with a chevy LS intake valve cut down to 1.65, tons of porting and relieving, mild custom grind cam, and 9.3:1 compression, governed at 3800.

The hottest Ive ever seen the oil was about 160 degrees, and that was on a 85 degree day, yanking a plow through the dirt.

My main concern was cooking oil vs cylinder head temps, but have learned that oil temp on a splasher isnt going to tell us much. Theres no doubt in my mind the oil temp at the big end of the rod is a lot more than 150 degrees.

We'd see as much as 475-500 degrees head temp back in the briggs kart days without issues, and also think about the Harleys with anywhere from 50-100+hp and NO fans at all to help cool em.

When i ran Honda GX200s we would remove fan blades until we got a peak head temp around 425⁰ and that was really as hot as we got, but we were only turning 6800 with 12oz of 0wt oil, never hurt anything...even with 40 lap features immediately after a 25 lap heat.

[Snoopy11 5,714]

3 hours ago, RED-Z06 said:

When i ran Honda GX200s we would remove fan blades until we got a peak head temp around 425⁰ and that was really as hot as we got, but we were only turning 6800 with 12oz of 0wt oil, never hurt anything...even with 40 lap features immediately after a 25 lap heat.

I am quite sure the exhaust was... very ...hot...

 

I know that guys do run their engines up that high in temp... just not reliable in my perspective for anything outside of racing. Even then... I question the advantage...?

 

Also... wouldn't it be easier to tape the air shroud... rather than remove the fan blades?

 

Don

[RED-Z06 2,221]

10 minutes ago, Snoopy11 said:

I am quite sure the exhaust was... very ...hot...

 

I know that guys do run their engines up that high in temp... just not reliable in my perspective for anything outside of racing. Even then... I question the advantage...?

 

Also... wouldn't it be easier to tape the air shroud... rather than remove the fan blades?

 

Don

Came down to performance, we ran timed laps and various temps from 325 to 450 and 410-430 the engine was faster.  Removing the fan blades lowered rotating mass also, we had multiple fans in the tool box to bolt on with various arrangements of blades missing from like..4 total blades to a full fan..in the winter we could run the 4 blade fan.  But yeah less drag and less mass.  We ran wrapped exhaust to keep the exhaust as hot as possible, this also increased power.

[Snoopy11 5,714]

I run billet flywheels, so the fan is machined into the flywheel.

 

Don