Differences in Kohler Engines

[fmints]

I've looked at the manuals and I can't find any info on the difference between a CH23 Kohler and a CH25 Kohler. They share the same stroke, and piston (not too sure about the piston). So my questions are: What makes a 23 a 23 and a 25 a 25? Is it the cam, or heads or simply bigger jets in the carb?

Fred

[JoeMeg]

Don't quote me but I think the diff is the bore diameter and the way the head fits over the combustion chamber.IE; the 23 is going to be smaller dia and will so to speak "hang over" the bore of the 25. I don't think there will be any mechanical interference issues but the comb chamber will certainly not be what was intended from design.Again,not positive,just thinkin.

Joe.

[fmints]

Don't quote me but I think the diff is the bore diameter and the way the head fits over the combustion chamber.IE; the 23 is going to be smaller dia and will so to speak "hang over" the bore of the 25. I don't think there will be any mechanical interference issues but the comb chamber will certainly not be what was intended from design.Again,not positive,just thinkin.

Joe.

So using your theory, if i bore the cylinder to fit 25hp pistons, then it will be a 25hp? Yup I do beleive that you are right. I just found a manual, and the 25hp has a bore size of 3.27in (83mm) and the 23 has a bore size of 3.2in (80mm). So i beleive that would be all that it would need to make the other 2 horsepower. The heads, cam, and carb should all be the same.

This question came to my mind, because I'm an adrenaline junkie, and I always want to go faster. I was thinking of ways,,(cheap ways) to make more torque and horse power from my stock and governed 23hp. I have thought about taking the govenor out, but that doesn't make more hp, just lets you rev up higher (be careful because the stock flywheel can only hold up to 5500 rpm's). For increased rpm's, stiffer rods, valve springs and an advancing flywheel key will get you there safely. A cam will surely give me more hp with bigger carb jets. Ive seen and read that aluminum flywheels and dyna ignition coils will increase hp and rpms also, but won't allow you to have a charging system which is need for our machines. Im just saying, Im looking towards the future,,,,, I WILL WANT MORE POWER,,,,, but want to know the different ways to setup my powerplant to acheive this goal.

Fred

[Dan67]

Fred, If you want more power I have just the idea to get you rolling. Miniature Gas-Turbine. I know you are now intrigued and cannot resist the urge to Google it. But first a teaser..

RUNNING TURBINE ENGINE ON TEST STAND | eBay

[fmints]

Fred, If you want more power I have just the idea to get you rolling. Miniature Gas-Turbine. I know you are now intrigued and cannot resist the urge to Google it. But first a teaser..

RUNNING TURBINE ENGINE ON TEST STAND | eBay

Yeah turbine, I have thought of that. Not really cost-effective. very expensive,,, but I have seen a turbine that weighs 33lbs push out over 240hp. Thanks dude, but i don't want to ruin someones weekend because my "Turbine Hustler" started a forest fire. Also, turbines are full throttle engines, in my opinion, not really practical. It would be cool to literally blow everyone away as I fast by them!!

[Tomo]

hi
Depends on the series of kohler engines
kohler command pro 725cc 83mm bore 25hp
kohler unknown series 675cc bore smaller than above 25hp [uncommon combination ]

The small block kohler in 725cc is presented 83 mm bore
25 hp carb
26hp efi
27hp carb
28 hp efi

From memory only the bore size is different ,stroke all the same in small block

tomo

[fmints]

hi
Depends on the series of kohler engines
kohler command pro 725cc 83mm bore 25hp
kohler unknown series 675cc bore smaller than above 25hp [uncommon combination ]

The small block kohler in 725cc is presented 83 mm bore
25 hp carb
26hp efi
27hp carb
28 hp efi

From memory only the bore size is different ,stroke all the same in small block

tomo

Thanks for the info, but are the cam, heads and carbs also the same?

[thebuggyman1]

Fred, Unless I misunderstood, you are looking to squeek out just another 2 or so ponies out of that engine????? I think you will end up with a bunch of $$ into it for such little gain. Have you seen these? Generac 40hp Max 33hp net Horizontal Shaft Engine with no Muffler | eBay Now that's a justifiable increase in HP
I put the 40 horse Kohler in my bigfoot(maxII) only because I got it cheap enough. I originally planned on one of these.

[fmints]

Fred, Unless I misunderstood, you are looking to squeek out just another 2 or so ponies out of that engine????? I think you will end up with a bunch of $$ into it for such little gain. Have you seen these? Generac 40hp Max 33hp net Horizontal Shaft Engine with no Muffler | eBay Now that's a justifiable increase in HP
I put the 40 horse Kohler in my bigfoot(maxII) only because I got it cheap enough. I originally planned on one of these.

Jim, I have seen those engines made out of wisconsin, but I don't know the creditblity of the unit. The truth is, i got my kohler for pretty much free, and was just looking to see if i can get a few extra ponies without spending over $300. Do you know of anyone who used the Generac power plant? It seems to have all the bells and whistles. Thanks for your input, I will look further into one of these engines!
Fred

[thebuggyman1]

Tim (obsessed) puts the stock form into some Argos. He may be the one to give advise. What I do know is they are used on ALOT of generators. Coincidentally Generac brand. LOL I have heard they are smoother running with a lower idle speed and have lower fuel consumption. I have used the generators on jobsites and they work quite well.