MIKE - Steve's correct, I had tongue firmly-in-cheek with that comment about somebody mowing foot high grass in 3rd gear with a 7 HP CC.
The little K161/181's try really hard at jobs like mowing tall grass, blowing snow, some people even run tillers with them. But as Tim Allen always says, more HP is always a good thing. When I dropped a rebuilt K241 in the 72 back in 1985 it was more for running the snow blower than running the 38" mower deck. That 25% HP increase was really noticable when blowing snow.
Having run a brand new '63 Original for 2 yrs, then a brand new 1965 #70 with both K161 & 181 engines for ten years, then getting my #72 with a 2-3 yr old replacement K181 in it in 1981 I know what they can and can't do. That's why I put a K241 in the 72 and ran it for 20 yrs in 1985 then installed a K321 7 yrs ago.
One thing the larger engines do is last many many more hours since they don't have to work NEARLY as hard all the time.
Like Steve is saying, there's a HUGE difference between simply running a CC engine @ 3600 RPM, and working one at FULL LOAD. Once the K161 is making ALL 11 #/ft of torque at it's 2000-2500 RPM range, the K241 is just starting to get with the program, it's still got 30% more torque, 14+#/ft, it can produce @ 3600 RPM, so the throttle blade in the carb wouldn't be close to wide open, probably just a little over half open.
I could go into a l-o-n-g discussion of the benefits of long stroke engines and torque rise, but just compare the torque charts of the K161 & K181 engines. The ONLY difference between the two is an additional 1/4" longer stroke on the K181, piston bores are the same. And the K241/301/321/341(not shown) are all an additional 1/8"(K241) to 1/2" longer stroke than the K181 plus increased bore diameter.
You spend enough hours on a tractor seat doing fieldwork like plowing, disking, chisel plowing etc you get a good feel for what HP and torque are all about.
I had a similar discussion on another forum about 2 yrs ago with somebody who said a 7-8 HP tractor was just as powerful running around the yard not doing any work as a 14-16 HP tractor which I thought was complete nonsense. Once you add a load the real advantage becomes obvious. I have a story about a pair of identicle 320 HP semi-tractors/trailers with similar loads, only one was 400-500# heavier and the lighter truck ran off and left me running across I-80 in IL. Coming home that night I was 400# lighter and I ran off and left the other truck. Both trucks grossed around 74,000-75,000# +/-. Just shows what a half a percent increase in weight/load can do.
Ohhhh STEVE - Thank's for posting those HP/torque charts!
