Lawn mower engines

[Jack Zipper Zerkie]

I have a base Cobb 2045 that I love the engine is a Kohler 20 command unit with about 1700 hrs. I.m located in south Fl. and it,s 98 with high humidity. I been using full synth oil 10-30 w. The engine lost the main shaft bearing. I change the oil every 50 hrs. The Kohler says to run the engine at 3600 rpm for cooling reasons. When I use 3600 the water temp stays at 250 at the motor. I like to run at about 2900 rpm and still have very hot water. I have also changed the oil to 15-40 so hope the helps. So you lawn mower guys let me know what your rpms are and any other problems. Thank you jz.

 

[FFA]

5w30 synthetic. I too was told to run at 3600, but my water gets extremely hot. The hose does a little shake sometimes.

I did a sectional today and lowered the rpms to about 2500. Suction was good and the heat was controlled. 35/47

 

[Cleanworks]

I have a 18hp Honda with about 5000 hours on it, My tiny tach crapped out at 4700 hours and just replaced it. I run it at 3000 rpm. I use 30 weight synthetic oil. Change it every 100 hours and have the valves adjusted once a year. It still runs like new, even my mechanic can't believe it. A little maintenance goes a long way.

 

[BIG WOOD]

Have you done any research on replacing that oil cooler for a bigger one? I always thought those oil coolers were so tiny. It doesn't make any sense to me.

 

[Cleanworks]

Don't fix what ain't broke.

 

[BIG WOOD]

Don't fix what ain't broke.

I just think those things would last longer if they would hold half a quart more of oil and it had a longer time to cool down.

 

[Cleanworks]

How much longer do you want than 5000 hours? This is a $2200 engine and if It goes kaput any time soon, it's more than paid for itself. I'm curious as to how long it lasts.

 

[dealtimeman]

I seen well maintained motors go at 1000 hours and some even less.

I have seen on a Cobb unit that a buddy has go over 3500 hours and about 8 years on it with very little maintenance. And I mean hardly any maintanence at all and it keeps just going and going.

He is afraid to start doing maintenance on it now and it fail. (I know, I know)

So these small motors can go either way.

You can get a good one that is anything above 2500 hours.

You could get a decent or average one that lasts longer than 1500 hours.

You could get one that fails with less than 1500 hours.

And this from all manufactures of engines as I have seen many Briggs and Stratton and Hondas go the distance just like kohlers.





S

 

[Goomer]

I been using full synth oil 10-30 w.

You using automotive oils, or air-cooled engine specific oils?

2 different animals.

Automotive oils are bad choices for air-cooled engines since they no longer contain the Zinc anti-wear additives that they once did since they have been regulated out in the best interest of catalytic converters and emission standards, but still robust in air-cooled engine specific oils.

It is the Zinc component that will offer added protection under the high heat conditions found in air-cooled engines which can fry the standard anti-wear components common in automotive oils that are designed for cooler running water cooled auto engines, whether Dino or the vast majority of synthetic other that a very few super-premium ones like a few Royal Purple or AMS blends and some racing oils.

At higher heat the Zinc will form a protective film between the hottest metal-to-metal contact surfaces and remain an effective component of the oil, as opposed to automotive anti-wear components which will burn out under higher temps likely sooner than later, and reduce the oils performance even further.

 

[Goomer]

I use 30 weight synthetic oil.

A lot can be said for straight 30 oil since it is more of an unadulterated base stock that does not contain the additives needed to make them multi grade, which can also degrade prematurely under the higher heat of air-cooled engines.

 

[Cleanworks]

A lot can be said for straight 30 oil since it is more of an unadulterated base stock that does not contain the additives needed to make them multi grade, which can also degrade prematurely under the higher heat of air-cooled engines.

Good comment, actually, I was told that by an engineer.

 

[Goomer]

Good comment, actually, I was told that by an engineer.

Spent many a sleepless nights on Bobistheoilguy.

The guys over there take their oils real seriously, so much so that they will send a sample of their used oil out for analysis, and proceed to discuss/debate the results based on what metals and other components are present in the used oil, and if these results may be indicative of a particular condition, or even specific to an individual part or component group, and also "how well" it held up after XXX miles.

Interesting stuff.

 

[Spurlington]

I also called Kohler direct and they recommended running it at 3600rpms because it needed the additional air to help cool it. Im on my 3rd engine in 14-15 yrs with a little over 7k hours. Replaced engine around the 3k hr mark both times and not because it didnt run but because it was leaking oil around the gaskets. I was quoted about $6-700 for a rebuild but bought new instead since I was getting them for $1400 new.

I run mine between 3100 -3200 and the water gets violently hot in the summer months. Im actually thinking of going back to propane because my system gets too hot if I fart around working on specialty spots. The solenoid kicks it back into the fresh tank (which I could redirect to the waste if I wanted to) - which creates a hotter tank that causes the solenoid to keep dumping - which has caused my pump to shut down because it dosent allow high temp (160 max?) to flow. I think running a propane system will relieve the pressure on the engine making it last a bit longer. Not to mention I like controlled heat

I was thinking of running a fan to help blow the heat outta the van .. maybe one to draw cooler air from the cab facing the engine.

 

[BIG WOOD]

I also called Kohler direct and they recommended running it at 3600rpms because it needed the additional air to help cool it. Im on my 3rd engine in 14-15 yrs with a little over 7k hours. Replaced engine around the 3k hr mark both times and not because it didnt run but because it was leaking oil around the seals. I was quoted about $6-700 for a rebuild but bought new instead since I was getting them for $1400 new.

I run mine between 3100 -3200 and the water gets violently hot in the summer months. Im actually thinking of going back to propane because my system gets too hot if I fart around working on specialty spots. The solenoid kicks it back into the fresh tank (which I could redirect to the waste if I wanted to) - which creates a hotter tank that causes the solenoid to keep dumping - which has caused my pump to shut down because it dosent allow high temp (160 max?) to flow. I think running a propane system will relieve the pressure on the engine making it last a bit longer. Not to mention I like controlled heat

I was thinking of running a fan to help blow the heat outta the van .. maybe one to draw cooler air from the cab facing the engine.

What model truckmount is that?

 

[Spurlington]

Hurricane with upgraded heat exchanger from Johns hot heat exchanger and I also upgraded the regulator to do tile.

 

[Larry Cobb]

As Frank mentions, the Zinc additive package is needed for air-cooled engines.
You can get that in a diesel oil or a Racing oil like Valvoline.
As the engine ages, slightly thicker oil is required.

 

[Cleanworks]

It's actually quite the insult to call them lawn mower engines. These are high quality industrial engines, designed to take a beating. They are used in everything from, industrial generators, cement mixers, air compressors and yes, even carpet cleaners. You'll see these engines out in the oil fields, gold mines, etc, with minimal protection amd maintenance and yet, they still run.

 

[Loren Egland]

The answer might be to do what Steam Way did with their Powermatic decades ago. They simply run the oil through a copper line coiled in the 5 gallon fresh water holding tank. The old units had an engine temperature gauge that showed a 30 degree drop in engine operating temperature compares to air cooled only.

Of course the water temperature has nothing to do with engine speed due to the kerosene burner.

My Kohler 25 horse air cooled (plus water tank oil cooler) is running strong with over 4000 hours. I have run them up to 5500 hours and then sold the unit for a newer one. Have heard of others that have lasted 9000 hours.

 

[jcooper]

You using automotive oils, or air-cooled engine specific oils?

So, generally speaking Kohler motors should use Kohler oil?

As Frank mentions, the Zinc additive package is needed for air-cooled engines.

How would I know if the oil has a zink additive?

 

[Goomer]

So, generally speaking Kohler motors should use Kohler oil?

Surely the safest of bets since they made the engine.

In the vast market of other products, especially the ultra-premium ones, are there better options?

I'm sure there are.

How would I know if the oil has a zink additive?

I think it is safe to assume that the vast majority of honest air-cooled oils incorporate Zinc into their blends as it's importance under high temperatures is oil 101, so I would not question it's presence, but at what levels?

Some automotive blends will have small concentrations of Zinc, but must stay below govt. regulations of XXX ppm, highest being racing and diesel blends.

Zinc content is always a hot topic on bobistheoilguy where you can find the results of independent sample analysis of most oils.

If one feels the desire to explore the ultra-premium world of motor oils that likely wont be readily available to you locally like Redline....AMSOIL, Royal Purple, and some others, it's a cool spot to check out.

They obsessively compare oils directly against one another like we compare presprays.

Some things always seemed to carry buku weight there in any direct comparison between 2 synthetic products. One was always the Zinc content of the oil, and the other was the classification of it's synthetic base-stock and whether a particular product was Group 1, Group 2 3 4 or 5 class base-stock, or a blend of more than one of the different class stocks.

The 12-15+ buck a quart stuff is that expensive for a reason.

For some odd reason I found the topic interesting.

So much so that I experienced a minor nervous breakdown from the stress of obsessing over which oil to use and the inevitable doom that would surely ensue if I was wrong.

I'm better now.

 

[Mikey P]

Refuce your lift from 17 down to 14..

 

[Jim Williams]

I got over 10,000 hours out of my first Kohler engine on my White magic, but I never ran it at full speed. Finally blew a head gasket. I always used 5w-30 and the engine was a 22 HP air cooled.

 

[dealtimeman]

You had an exceptional motor!

 

[Mrice]

@Goomer, you've done a lot of reading on the subject, what readily available oil would you think might be best, specifically?

 

[Nate The Great]

@Goomer, you've done a lot of reading on the subject, what readily available oil would you think might be best, specifically?

x2... I don't want to read up on it, so splain it in Marty's term for me... Honda GX630, which oil should I be using? @Goomer

 

[dealtimeman]

He is r4comending to use a small engine motor oil like if you own a Honda use Honda brand small engine or if you own a Yamaha use yamilube so on and so forth.

 

[Jack Zipper Zerkie]

Where is the the best place to buy a new kohler 20 hp command engine ? Thank you jz.

 

[Spurlington]

http://www.smallenginewarehouse.com/CH640-3138.html

$1500 for a 20hp​

 

[Goomer]

He is r4comending to use a small engine motor oil like if you own a Honda use Honda brand small engine or if you own a Yamaha use yamilube so on and so forth.

Pretty much so, assuming the manufacturer offers a FULL synthetic version in my opinion.

Outside of that, unless one is willing to take the full leap to ultra-premium full-$ynthetic$, I would not waste my time trying anything else in between.

Either shit or get off the bowl.

If you got the itch for some reason or another to use something other than a manufacturers full-synthetic product, don't sell yourself short dicking around in AutoZone and WallyWord looking for a better alternative among common brands of generally similar quality.

Unless your willing to go the whole hog and drop some real coin and get serious about your oil, then don't waste your time.

If your not willing to take the leap into ultra-premium$ like AMSoil, Royal Purple, Redline, etc., which are generally higher in Group III and POA Group IV content, then there is no valid reason you should be waste your time contemplating any other product of lower quality.

http://www.machinerylubrication.com/Read/29113/base-oil-groups

 

[Cleanworks]

Great article Goomer. I use Honda small engine oil (full synthetic). I pay the big bucks for it. About 12 bucks a quart. My machine takes about 1.2 quarts every 100 hours, plus about 20 bucks for a Honda oil filter. Costs me a whole 32 bucks for an oil change. I could save $9 if I used ordinary oil. I could also changes engines every 2000 hrs like some. 5000 hours and the only thing that ever broke was one coil. Got to go and get my valves reset soon.