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312Hydro

Kohler 20 Magnum or Onan 20 , Whats the best engine?

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312Hydro

Got to thinking about the M20 while reading about the 420LSE. I am somewhat familiar with the Onan history but what about that Kohler? How does it compare in longevity,servicing,etc? Any quirks ?  I'm also wondering why WH didn't continue with the Kohler engines and went with the Onan.Was it a Toro thing?

 

attachment_zpsc228f825.jpg vs wh004.jpg

Edited by 312Hydro
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wh500special

I'm not an engine expert, so can't speak to the "which is better" aspect of things very accurately but it doesn't stop me from having opinions. I have both types and think they compare favorably. Properly tuned, they both fire up quickly and run smoothly. To me the Onan sounds better, but that's a personal preference.

Wheel Horse changed to the Onan 20 hp from the Kohler Magnums since the Onan reportedly put out more torque (I'm not speculating here, this came from a source who worked at WH at the time). This was desireable for the 60" deck under the new 1988 520HC. I'd imagine to keep things consistent across the product range, the 16 and 18 Onans were employed on the 416, 516, and 518.

Onan twins are known for running thousands of hours in applications other than Wheel Horses. They have a very good reputation outside our world.

Steve

Edited by wh500special

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Tankman

Loved Kohlers for many, many years. All one cylinder cast blocks.

Easy to work on, reliable.

 

Was always skeptical 'bout Onan's. Changed my mind.

 

Picked up a '90 520-8 Onan 2-cyl. Runs like a Horse, never a strain using a 48" SD deck and in winter, push plenty of white stuff with a 48" dozer / plow blade.

 

Semi-retired, I spend a lot of pleasureable time with my Herd. Oil changes, air cleaners, plugs, cleaning, Never-Seez®, PB Blaster, belts, tires, deck blades, grease. All are like new......always.

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JackC

The ONAN P Series put out significantly more torque at lower RPMS than the Kohlers.

 

See attached PDF from a 1988 sales manual.  You will need to rotate the image counterclockwise with your PDF viewer.

 

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Hodge71

Speaking from the only experience I can provide...I will take the Kohler anyday. I know how my brother's C-195's ate up the grass with the 60 inch deck and the sound was amazing. A 520 with a 60 inch deck....just doesn't do it for me. Plus I never heard of a Kohler chucking valve seats just cuz it felt like it. I'm sure the Magnum 20 has even more power than the KT-19. I cant wait until this 416 with the Onan is done and outta here!!! 

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Tankman

The only pitfall to date with my 20 hp Onan, "One thirsty engine!"

 

Torque! The Onan has it!

 

Red is for the blood we shed.

Edited by Tankman

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cyrus

My father had a 16 hp hydro, the old kohler one lunger.....and I was partial to an old john deere 60 that I drove as kid on the farm......needless to say I liked the lumpy sound of the old style power......however, when pops traded the old wh in on the his new 416 hydro back in the mid 90's.....well, the boxer style onan won me over....love that smooth power, and with the proper tuned muffler they sound great too....

Edited by cyrus

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leeave96

The ONAN P Series put out significantly more torque at lower RPMS than the Kohlers.

 

See attached PDF from a 1988 sales manual.  You will need to rotate the image counterclockwise with your PDF viewer.

 

attachicon.gifONAN vs Other - torque.pdf

That PDF makes the Onan sound like a great engine!

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312Hydro

Thanks for all the input guys. What had me thinking was that you see all the 520's getting re powered when the Onan goes bad, but I've never seen anyone mention the M20 as a repower.

 

"Onan twins are known for running thousands of hours in applications other than Wheel Horses. They have a very good reputation outside our world." -wh500special

 

There must not be much shrouding on the Onan welders and generators?  It would be great to talk to the WH engineers to get the inside story on engine selection and why these choices were made. I like my 520h (even though I have to pull the carb off to clean as it's running rough) but the thought of a Kohler Magnum 20 in it sounds good too if the Onan ever goes south.

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JackC

"Onan twins are known for running thousands of hours in applications other than Wheel Horses. They have a very good reputation outside our world." -wh500special

 

The P series needs a large amount of cooling air.  I believe overheating is the major issue with the ONAN application on wheel horse 500 and 400 series tractors.  Any ONAN on a generator does not run into this wheel horse specific problem.  This happens often with 42 and 48 inch side discharge decks that shoot some clippings out the front and on a hot day could overheat the engine.  The ONAN P series may also need more frequent valve adjustment and de-carbon service than the Kohler equivalent flat head twins.

 

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Hodge71

Toro made the Kohler vs Onan decision just like John Deere and every other company. Onan was cheaper and thats all that mattered. I don't believe the Ponds would have made the switch from Kohler of they were still in power at the time. They tried Clinton, and Lauson, Techy and Briggs but always stayed with Kohler in the end. They knew where the real power and reliability came from... the big K!!

 

Wheel Horse makes it...Kohler shakes it!! 

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decksetter

Wheel Horse makes it...Kohler shakes it!!

That's true, onans are too smooth to shake it.

I'm an onan guy myself, but I haven't had a Kohler twin. If they make the same power and require less maintenance I wouldn't mind giving one a try.

I haven't seen an onan with problems that I was convinced had it's routine maintenance / valve adjustments. The rear intake valve ends up holding open, then the valve seat will pop loose. Keep valves adjusted and it should run thousands of hours.

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kaiser

"Onan twins are known for running thousands of hours in applications other than Wheel Horses. They have a very good reputation outside our world." -wh500special

 

The P series needs a large amount of cooling air.  I believe overheating is the major issue with the ONAN application on wheel horse 500 and 400 series tractors.  Any ONAN on a generator does not run into this wheel horse specific problem.  This happens often with 42 and 48 inch side discharge decks that shoot some clippings out the front and on a hot day could overheat the engine.  The ONAN P series may also need more frequent valve adjustment and de-carbon service than the Kohler equivalent flat head twins.

 

attachicon.gifP5180168.JPG

 

that's me on just about any mowing day, but i've got the 16hp twin briggs. i lean over alot to clean that off. the slots in the onan grille are pretty big, i wonder how much gets sucked in.

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wh500special

Toro made the Kohler vs Onan decision just like John Deere and every other company. Onan was cheaper and thats all that mattered. I don't believe the Ponds would have made the switch from Kohler of they were still in power at the time. They tried Clinton, and Lauson, Techy and Briggs but always stayed with Kohler in the end. They knew where the real power and reliability came from... the big K!!

 

Wheel Horse makes it...Kohler shakes it!! 

 

You could be right about the economics of things since I have no idea what either line of engines cost in the late '80's, but that really wasn't the case for WH switching to the 20 horse Onan in the 520.  It was about the torque. 

 

Unless Deere has changed the way they do business, they put much more effort into their engineering decisions than just economics.  In my career I've had Deere as a customer on multiple occasions in vastly different product categories and their requirements have always been centered on providing the optimum component for the application.   They certainly don't "overbuy" if not necessary, but they really put effort in to make sure they don't compromise reliablity to save a few dollars.

 

Deere probably drifted from Kohler after the KT's in the 317's cost them so much in way of money and reputation.  If the Onans were indeed cheaper it would have been an even easier decision.

 

Kohler has a deserved reputation of building very durable, reliable small engines.  No doubt about it. I love my Kohlers from the smallest k90 to the Magnum 20.  But they've had their stinkers too (KV's, KT's, Triads, etc.).

 

I'm not trying to be overly critical here, but I suspect there was a lot more at play for these manufacturers than just cost.

 

Steve

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decksetter

Is the magnum a pressure lube setup? Does it have an oil filter? I've never had a chance to look at one.

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wh500special

Yes, the M20 is both pressure lubed and filtered.

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WildHorses

Our dealership was in Columbus, IN and dad has mentioned before that he talked to some Cummins engineers who worked on the Onan engine lineup back at that time (guys who just came in shopping for tractors). They said the Onan engine was originally built and designed for generator usage where the engine was meant to run at a lower RPM with less of a load most of the time. (They also didn't have to worry about dirt and debris buildup in the generator form.) The engineers belief was that the engine just wasn't well suited to high RPM constant load work like on a garden tractor. Dad didn't like to sell the Onan but I can recall a conversation he had with a Kohler rep (I think, might have been Wheel Horse but they were strictly asking about Kohler Twins) when asked why he didn't have any of the Kohler twin tractors on the floor, only Onan dad stated that anyone who had a KT series 1 engine wouldn't touch another one and that he felt the reliability wasn't established enough to push the twin Kohlers. Also being in Columbus, home of Cummins he felt it was in his best interest to carry the Cummins product Onan engine. Having said all that he won't own an Onan tractor to this day and he only has one Kohler twin and that's on a 420-LSE. 

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Skipper

Magnum 20 would be my choice out of those two. Less prone to overly expensive repairs and faults IMO. The older KT's vere also more prone to faults, not quite so much the magnums, but they could fail too. Always liked the kohler soundtrack better.

 

On the torque part of it: I have run many 60" 520's and some C195's with same deck, with KT19 and Mag 20 engines. Not much difference IMO if anything really noticeable at all. The kohler v-twin in the Xi series and newer however, is far superior to any of these old engines in all aspects IMO. That would be a repower and an upgrade at the same time. :-)

 

Very old thread by the way :-)

Edited by Skipper
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tom2p


Onan powered Wheel Horse tractors are a great option if you prefer Wheel Horse and cut a lot of grass 


 

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tom2p


a lot of grass 

 

this is Onan grass (or zero turn)

 

WVhillbilly and others cut more 

 

 

C4B62F82-D2CC-4634-86B2-A88ADED4B2B7.jpeg

AD175096-6523-4C4E-9799-65CEAE95CAE7.jpeg

77C78CF7-175A-4B7D-8123-DC5F4443AC31.jpeg

F4F71FFA-E801-4E62-9319-39C8ED4FE2F9.jpeg

Edited by tom2p
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kasey54

If I had a choice, Twin mag, or Twin Onan Id grab the Kohler. I wouldn't turn down either. Ithink the Onan is the best sounding 

twin ever.

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onanparts.com
On 5/27/2020 at 11:24 PM, WildHorses said:

Our dealership was in Columbus, IN and dad has mentioned before that he talked to some Cummins engineers who worked on the Onan engine lineup back at that time (guys who just came in shopping for tractors). They said the Onan engine was originally built and designed for generator usage where the engine was meant to run at a lower RPM with less of a load most of the time. (They also didn't have to worry about dirt and debris buildup in the generator form.) The engineers belief was that the engine just wasn't well suited to high RPM constant load work like on a garden tractor.

 

If this were true, why were there millions of Onan powered Miller, Lincoln and Hobart portable welders made and designed to run at 3600-3700 RPM at full load every day, all day? Many are still on the job even though they were made back in the 80's and 90's. These welders had two operating speeds, idle and full speed. Then there are the millions of Onan powered tractors still on the job. Onan engines are and were designed, engineered and manufactured for commercial/industrial applications. Overbuilt. High speed, low speed, any speed. Peak torque right around 2200-2400 RPM.

 

Take this overbuilt design and reduce it's operating RPM by 50% and you now have a nearly bullet proof 1800 RPM quiet and dependable generator. A win win situation. Onan engines were originally designed for generators, back in the 1930's! The track record of "High RPM" Onan engines in tractors and welders and many many other applications is proof those so called Cummins engineers back then were full of BS! 

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onanparts.com

This is a published Dyno chart for the Onan P220G. Most GT and welder applications had the XSL, Extended Service Life package so the maximum ratings on the graph can be used. Sweet spot for torque is between 1800-2800 RPM. That's a nice wide range! A major reason the Onan's are so popular, no need to wind them up to 3600 RPM. But if you do, no problem! :) Note Onan states "Recommended for variable speed or continuous duty at 3600 RPM" 

This publication was NOT put out by the Onan marketing dept. They didn't need to play games with real specs.

 

 

 

 

 

p220gcopy1.jpg

P220Gpowercurves1.jpg

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tom2p


what is the XSL / extended service life package ?

 

 

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onanparts.com
3 minutes ago, tom2p said:


what is the XSL / extended service life package ?

 

 

See under the Optional Features list. Bottom. Hard faced exhaust valves and chrome piston compression rings. Usually just the top groove ring was chrome. The oil filters were not optional as stated, they screwed up there! Became standard on all the Performer P-Series engines beginning in 1986. Prior to that oil filters were optional.

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