K181 RPM question

[motor12 367]

My 854 is retired, no longer a working tractor. The K181 engine runs great. My question is what is a good/safe RPM to operate the 8 HP Kolher. Is the 3600 RPM max recommended for all operation or just under load. Trying to be kind to an old motor..

[Coadster32 793]

If it helps at all, I rebuilt my K181 a few years back, and use it for plowing duty in the wintertime. Otherwise it sees no real work. I kept the governor down just to not tire the motor out and give it longevity, just as you seem to be seeking. The motor is designed to make 8hp @ 3600rpm. Below that, it won't make the full rating. (Keep in mind what 8hp really is geared behind a WH tranny.) I have plowed 13inches of snow @ full blade without reaching max rpm. I have no real need to turn mine up.  Hope this helps.

 

http://vid400.photobucket.com/albums/pp82/Coadster32/pics053.mp4

[motor12 367]

I like the video, your Wheel Horse hardly sounds like it's breaking a sweat.

[jrc0528 20]

Keep in mind that air cooling and splash lube rely on the engine RPMs to work correctly.

[Fordiesel69 214]

Until I rebuilt a H60 ariens snowblower engine, I always thought lower is better,  the K181 has a long dipper, but will need RPM to splash.  I would recommend 3600 with little load, over less rpm with more load.  The 8HP is the largest of the small block, and does not last as long as a 6HP or for example a K341 is at the largest of the big block and will not last as long as the K241 10HP.  Just my opinion.

[motor12 367]

Until I rebuilt a H60 ariens snowblower engine, I always thought lower is better,  the K181 has a long dipper, but will need RPM to splash.  I would recommend 3600 with little load, over less rpm with more load.  The 8HP is the largest of the small block, and does not last as long as a 6HP or for example a K341 is at the largest of the big block and will not last as long as the K241 10HP.  Just my opinion.

Thanks, I always thought low RPM meant longevity, I understand the need to spin parts faster in order to splash some oil around, makes sense to me.

[rmaynard 14,897]

Kohler recommends a low speed idle of about 1200 +/- 75 rpm's. Anything below that and you are not slinging enough oil to lubricate the innerds properly.  As Chris stated above, full horsepower is achieved at 3600 rpm. Since you don't need full power just to putter around, my theory is that any speed between 1200 and 3600 rpm is adequate.

[buckrancher 2,675]

.  The 8HP is the largest of the small block, and does not last as long as a 6HP .  Just my opinion.

I was just wondering what you based your opinion on considering the 6hp 7hp and 8hp kohler motors basically are all the same

[Coadster32 793]

Kohler recommends a low speed idle of about 1200 +/- 75 rpm's. Anything below that and you are not slinging enough oil to lubricate the innerds properly.  As Chris stated above, full horsepower is achieved at 3600 rpm. Since you don't need full power just to putter around, my theory is that any speed between 1200 and 3600 rpm is adequate.

 

My thoughts exactly.

[Fordiesel69 214]

I was just wondering what you based your opinion on considering the 6hp 7hp and 8hp kohler motors basically are all the same

If you look at the crankpin diameter and width, it stays the same as the piston diameter increases.  When you increase the piston, you exert more force on te crankpin / rod surface. 

[rmaynard 14,897]

If you look at the crankpin diameter and width, it stays the same as the piston diameter increases.  When you increase the piston, you exert more force on te crankpin / rod surface. 

If I'm not mistaken, the pistons are the same size, just the stroke is different.

[buckrancher 2,675]

If you look at the crankpin diameter and width, it stays the same as the piston diameter increases.  When you increase the piston, you exert more force on te crankpin / rod surface. 

so you actually think .0625 is going to wear your motor out faster ?

Edited December 2, 2014 by buckrancher