Another Addition To My Herd

[Handy Don 14,858]

1 hour ago, Achto said:

 

He did say that the engine was not exactly happy about the whole affair. 

I've never seen that one either. And yeah, I’d say only the last couple years of short or “mid" frames with a 10 or 12hp would be able to run that

[WHX?? 53,079]

Yeah look what HP they use to spin a 42 nowadays ... 18 - 20 twins and they used a 10 back in '65. 

[kpinnc 15,931]

30 minutes ago, WHX?? said:

Yeah look what HP they use to spin a 42 nowadays ... 18 - 20 twins and they used a 10 back in '65. 

 

Leaded gas, cast iron block, and a flywheel that weights more than the whole engine nowadays. Definitely made a difference! 

[Handy Don 14,858]

10 hours ago, kpinnc said:

 

Leaded gas, cast iron block, and a flywheel that weights more than the whole engine nowadays. Definitely made a difference! 

 (sorta?!)

Leaded gas achieved higher octane via the (highly toxic) lead. Unleaded does it using other (less toxic) additives. Energy content is close to the same. That said, the higher the octane the higher the compression ratio can be without engine knock. But do newer engines have lower compression? I don’t know. 

The heavier flywheel is, I agree, a big factor in smoothing out load variations, but something had to build and sustain the momentum!

I think the biggest factor is rate of fuel consumption as part of driving down emissions. I believe that less fuel consumed is not fully offset by increased efficiency so there is a net loss of usable power. 

That said, IMHO, the single main factor is that consumers are more number conscious than ever (BIGGER is BETTER!). Higher horsepower must be better! My guess is that most of these 18-25 horse units are just not really using the horsepower.  

 

[kpinnc 15,931]

6 hours ago, Handy Don said:

I believe that less fuel consumed is not fully offset by increased efficiency so there is a net loss of usable power. 

That said, IMHO, the single main factor is that consumers are more number conscious than ever (BIGGER is BETTER!). Higher horsepower must be better! My guess is that most of these 18-25 horse units are just not really using the horsepower.  

 

Agreed. I also think cast iron blocks deliver more power just through rigidity to a point. 

 

Again, it's multiple little things adding up to a bigger total. No doubt that newer designs are more efficient. My 23hp Vanguard uses about the same fuel as my K181 8hp at full throttle. Fuel mix ratios definitely can result in smoother running on the old Kohlers, but being too rich or lean on newer engines may keep them from running at all!

 

 

 

 

[Achto 30,023]

One thing that I believe the new engines lack is torque. I believe this is because the stroke is shorter on new engines. Longer stroke = more torque.

[WHX?? 53,079]

On 11/11/2025 at 8:55 AM, Handy Don said:

My guess is that most of these 18-25 horse units are just not really using the horsepower. 

Got a point there Don. MY Z turn spinning a 48 and two hydros never gets on the gov unless I shove it into tall weeds or use it for brush hogging. Yah it's green & yellow and I abuse it like I stole it. Well ... actually I did  it ... 

 

stroke is shorter on new engines.

 

Smoother power perhaps Dan? Cheaper to make fer sure. 

Edited November 13 by WHX??

[Achto 30,023]

7 hours ago, WHX?? said:

Smoother power perhaps Dan?

 

Over square engine

The main advantage of a short-stroke engine is its ability to achieve higher RPMs, which results in more horsepower. This is because the piston travels a shorter distance, allowing it to rev faster and reducing wear at high speeds. Additionally, their larger bore allows for larger intake and exhaust valves, leading to better airflow. 

 

Under square engine

The main advantage of a long stroke engine is improved low-end torque and thermal efficiency, making it good for applications like heavy loads and cruising. They are more fuel-efficient and provide smoother power delivery, but generally lack high-revving power. 

 

 Square engine. Normally my favorite, unless I really need more torque.

A square engine, with equal bore and stroke, offers a balance between torque and high-RPM power and can have advantages in compactness and reduced vibrations, especially in certain configurations. This balance makes it a versatile design suitable for a wide range of applications, from performance to general use. 

 

Kohler K181 and K301 are pretty close to being a square engine. The rest of the K models are over square.

 

A lot of the old Wisconsin engines are under square.

Edited November 13 by Achto