Older Kohler K17 using oil

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Sep 3, 2025
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I’ve got an early 80’s mower with a vertical shaft K17 series 2 that is air cooled and has an oil pump/filter. The guy I bought it from gave me gave me two quarts of oil and a filter so I used it when I noticed it was using oil. The oil he gave me was Kohler 10W30 synthetic and it used about half of a quart every 4 hours. I read up on it and it sounds like that should be expected when using a multigrade oil and that I should be using SAE 30. I made the switch and now it burns zero oil as long as I run the mower less than 1 hour. If I run it longer than that she burns oil. Does this mean it’s getting too hot when running that long? Also I filled it with 1.9 quarts like the manuals says and it was way over full so I drained it down to the full mark on the dipstick. I’m wondering if the dipstick is not for this engine or if I’m checking it wrong. The dipstick doesn’t screw in it just has the loop handle with the slide on metal cap that fits over the dipstick tube.

Should I be filling it past the full mark to use the recommended 1.9 quarts?

Is Kohler SAE 30 necessary? It costs 2x other SAE 30 oils.
 
You got an engine that's over 40 years old. It's likely worn out. I would just run a straight 40 weight or a 20w-50 major brand oil and just keep the oil level up. It is not necessary to use Kohler oil.

If you are sure it's being completely drained, I would put the correct amount of oil in it and mark the dipstick accordingly. If it has an oil filter, its contents is part of the 1.9 quart total. If you are not changing the filter, refill quantity needs to be lessened.

It could be running hot if debris is clogging the cooling fins. Clean everything up including under the flywheel cover.
 
how are you using the dipstick.. many of those that screw in you just touch it for the level.(not screw in)

I would use 15w40 such as delvac 1300. Cheap and works.. could reduce usage.

a modern 10w30 vs sae 30 wont be much difference in oil consumption.
 
You got an engine that's over 40 years old. It's likely worn out. I would just run a straight 40 weight or a 20w-50 major brand oil and just keep the oil level up. It is not necessary to use Kohler oil.

If you are sure it's being completely drained, I would put the correct amount of oil in it and mark the dipstick accordingly. If it has an oil filter, its contents is part of the 1.9 quart total. If you are not changing the filter, refill quantity needs to be lessened.

It could be running hot if debris is clogging the cooling fins. Clean everything up including under the flywheel cover.
The cooling fins on the drivers side were mostly clean. I had to open the shroud on that side to peck on the starter bending one day and I pressure washed it while the shroud was open. The reason I asked about oil brand was that an AI told me that Kohler, Briggs and Stratton, etc small engine oils are supposed to be engineered to better handle higher temps that happen in air cooled engines. I guess I could buy the cheap SAE30 at the farm store and see if the usage increases. AI also told me that a multigrade oil of any kind would speed up usage in this engine. I changed the oil filter when I serviced it. I had the drain side of the engine facing downhill. I filled it with the 1.9 quarts and ran the engine so the filter would fill up and then checked it to find it was substantially overfilled according to the dipstick. I guess my next move is to drain it and refill with 1.9 again and mark the dipstick at the higher level. I’m just leery of overfilling it.
 
how are you using the dipstick.. many of those that screw in you just touch it for the level.(not screw in)

I would use 15w40 such as delvac 1300. Cheap and works.. could reduce usage.

a modern 10w30 vs sae 30 wont be much difference in oil consumption.
I mentioned in the first post that it isn’t a screw in dipstick. It’s the style that was used on car engines for years. I also relayed that the Kohler 10w30 synthetic gets used much faster than the SAE30. The curious thing about the SAE30 is that the motor doesn’t burn any oil if I limit the run time to 1 hour. I mow about 5 acres and sometimes I mow about a quarter of it per day. It only burns the SAE30 on days when I mow half or all of it in one go. The 10w30 burns no matter how short the run time is. That fact doesn’t give me confidence that a heavier multigrade would fix the problem as the oil usage could be happening when the oil temp is low and the multigrade is acting like the lower viscosity end of the spectrum.
 
I mentioned in the first post that it isn’t a screw in dipstick. It’s the style that was used on car engines for years. I also relayed that the Kohler 10w30 synthetic gets used much faster than the SAE30. The curious thing about the SAE30 is that the motor doesn’t burn any oil if I limit the run time to 1 hour. I mow about 5 acres and sometimes I mow about a quarter of it per day. It only burns the SAE30 on days when I mow half or all of it in one go. The 10w30 burns no matter how short the run time is. That fact doesn’t give me confidence that a heavier multigrade would fix the problem as the oil usage could be happening when the oil temp is low and the multigrade is acting like the lower viscosity end of the spectrum.
What? At low(er) temperatures the oil is very thick just like any other oil. You're making the common misunderstanding about what the winter rating means, does not mean, and when. As was explained to you here:

 
Looks like he mentioned he is already using straight 30 weight.


OP it is an older engine that is a bit worn. Personally I would run 15w40 or a 20w50 in an air cooled engine that old and see if it helps with the consumption.
It is an old engine but it doesn’t leak or smoke. It runs great. I’ll probably try some 40W but I think that I’ve proven that a multigrade burns faster then the 30.
 
What? At low(er) temperatures the oil is very thick just like any other oil.
A multigrade behaves like the lower number at lower temps and like the higher number once the temp rises. I speculate that the 10w30 usage that I experienced is happening before the engine reaches operating temperature. The SAE30 level doesn’t drop unless I run the mower for several hours. I think the longer I run the mower the hotter it gets. 40w might be what I try next but I haven’t noticed any on the shelves around here. I need to get a compression tester to gauge how worn the engine might be.
 
I mentioned in the first post that it isn’t a screw in dipstick. It’s the style that was used on car engines for years. I also relayed that the Kohler 10w30 synthetic gets used much faster than the SAE30. The curious thing about the SAE30 is that the motor doesn’t burn any oil if I limit the run time to 1 hour. I mow about 5 acres and sometimes I mow about a quarter of it per day. It only burns the SAE30 on days when I mow half or all of it in one go. The 10w30 burns no matter how short the run time is. That fact doesn’t give me confidence that a heavier multigrade would fix the problem as the oil usage could be happening when the oil temp is low and the multigrade is acting like the lower viscosity end of the spectrum.
Your bricks of texts are hard to read on mobile I did miss that.

Screenshot_20260521_092606_Chrome.webp
 
personally would pull the plugs out and do a berrymans B12 piston soak. could have some coked up rings. after that i would fill with Mobil 1 0w-40. some of the best OTS oil for OPE and the only one i use.
 
A multigrade behaves like the lower number at lower temps and like the higher number once the temp rises. I speculate that the 10w30 usage that I experienced is happening before the engine reaches operating temperature. The SAE30 level doesn’t drop unless I run the mower for several hours. I think the longer I run the mower the hotter it gets. 40w might be what I try next but I haven’t noticed any on the shelves around here. I need to get a compression tester to gauge how worn the engine might be.
It meets the performance specifications for the winter rating at the tested temperature. Which is very low. It’s not a “5W” oil as compared to the oil being a 30-grade at the tested temperature.

The oil does not “thicken to a 30-grade” as it warms up.
 
A multigrade behaves like the lower number at lower temps and like the higher number once the temp rises. I speculate that the 10w30 usage that I experienced is happening before the engine reaches operating temperature. The SAE30 level doesn’t drop unless I run the mower for several hours. I think the longer I run the mower the hotter it gets. 40w might be what I try next but I haven’t noticed any on the shelves around here. I need to get a compression tester to gauge how worn the engine might be.
You speculate incorrectly. That oil, like any oil (especially a mono-grade) is much, much thicker at any temperature below normal operating temperature. Again, that's not what the winter rating means nor indicates.
 
There is nothing special about Briggs or Kohler SAE 30. 10w30 will be the same viscosity at operating temperature as an SAE 30 oil as well. I wouldn't trust AI to give good advice about oil, I've even had it give me incorrect info about oil capacity before. I'd try a 15w40 heavy duty oil like Rotella or Valvoline, or any good 20w50 and see if that helps. I've had good results using those two grades in older equipment.
 
I’ve got an early 80’s mower with a vertical shaft K17 series 2 that is air cooled and has an oil pump/filter.

Just curious, are you sure what model you have? A K17 Series II is a horizontal shaft engine. Can you find the actual model number on the block or shroud?

Looking online, the K series engines were predominantly horizontal shafts, the only vertical models were rather rare from back in the 60’s.
 
Just curious, are you sure what model you have? A K17 Series II is a horizontal shaft engine. Can you find the actual model number on the block or shroud?

Looking online, the K series engines were predominantly horizontal shafts, the only vertical models were rather rare from back in the 60’s.
I wonder if he has an opposed cylinder M17?
 
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