300 hours - clean combustion chamber, clean and lap valve seat surface

[WinterDeere]

Machine: Deere 757 ZTrak
Engine: Kawasaki 25 hp V-twin

Okay, most of us have (or have had) these ubiquitous Kawi V-twins on our mowers, we all know this engine. We all know it's good to check and/or adjust the valve clearance every few years, Deere happens to recommend 300 hours... all good. It's a clean and easy operation, no problem.

But they also recommend cleaning the combustion chambers and cleaning and lapping valve seat surfaces every 300 hours. Am I alone in thinking that's just insane? What are the rest of you doing?

 

[Racer4]

No experience with this particular engine, but I would not be tearing off the heads for any reason every 300 hours. That’s ridiculous.

Dad had a JD 325 with over 1000 hours on a 17hp Kawa single. Never had an issue. Tractor is now run by my FIL at his house. Still going.

I’ve got 600 hours on my Wheel Horse 314-8 and never pulled the head for cleaning.

 

[ericm979]

But they also recommend cleaning the combustion chambers and cleaning and lapping valve seat surfaces every 300 hours.

The 1940s called and wants their maintenance schedule back.

I'd check/adjust the valves and run it. What do new heads cost for it? A new head for the single cylinder B&S on my 27 year old Deere Sabre costs all of $250.

 

[WinterDeere]

...I would not be tearing off the heads for any reason every 300 hours. That’s ridiculous.

Agreed. I didn't even consider it at 300 hours, or at 600 hours. Now I'm at 1000 hours, and wondering if I should eventually do it.

All I've done so far is fluid changes every year, carb and idle adjust around 600 hours, and check the valve adjustment every 300 hours.

 

[Runner]

It's not just John Deere requiring it. I have a Cub Cadet with the Kawi FS730V engine and the engine manual from Kawi specifies cleaning the combustion chamber, check/adjust valves and clean and lap the valve surfaces at 300 hrs.

The manual for my Kawi Mule says to check/adjust valves at 50 hours.

On the other hand, the manual for my 1989 JD 185 with Kawi engine doesn't mention any of those items, they've never been done and it still runs fine.

I'm seriously considering just blowing it off.

 

[RandyT]

Some of the maintenance intervals for small engines are leftovers from the L or flat head days where carbon buildup was common and valve clearances needing adjustment along with cleaning and adjusting the points.

 

[WinterDeere]

Some of the maintenance intervals for small engines are leftovers from the L or flat head days where carbon buildup was common and valve clearances needing adjustment along with cleaning and adjusting the points.

Maybe, but I’d honestly be surprised if that’s the case for these Kawi 25 hp V-twins, as their most common application is commercial mowers that run 40-60 hours per week in-season.

 

[dfkrug]

It's not just John Deere requiring it. I have a Cub Cadet with the Kawi FS730V engine and the engine manual from Kawi specifies cleaning the combustion chamber, check/adjust valves and clean and lap the valve surfaces at 300 hrs.

Yes, that is absurd and you should ignore it.

These Kawasakis do have some weaknesses, which are infamous. The company struggled to make cam gears that would last. Plastic is not the best material for cam gears, but Honda and Kohler use them in some engines and their records seem to be better.

That said, the cam gears are so bad in Kawa twins that there have been cheap aftermarket kits available for years. Problem is, you have to pull the engine and take it completely apart.

I got a 4x6 Gator here a couple of years ago, where someone attempted the cam gear update, and did it incorrectly. He lost the oil pump spring, for one.

All of these OHVs need periodic attention to their valve clearances, but it is usually very easy. Hard to start is the clue.

Also, it you have a diaphragm fuel pump, E10 fuel makes the rubber stiff, and they often need replacement every few years.

 

[KennyG]

Valve adjustment, oil and filter changes on schedule. Everything else should be what we used to call RTF (Run To Failure).

 

[WinterDeere]

Valve adjustment, oil and filter changes on schedule. Everything else should be what we used to call RTF (Run To Failure).

Thanks, guys. That's the plan I'm presently on, just wanted to make sure I was in good company.

 

[RandyT]

Yes, that is absurd and you should ignore it.

These Kawasakis do have some weaknesses, which are infamous. The company struggled to make cam gears that would last. Plastic is not the best material for cam gears, but Honda and Kohler use them in some engines and their records seem to be better.

That said, the cam gears are so bad in Kawa twins that there have been cheap aftermarket kits available for years. Problem is, you have to pull the engine and take it completely apart.

I got a 4x6 Gator here a couple of years ago, where someone attempted the cam gear update, and did it incorrectly. He lost the oil pump spring, for one.

All of these OHVs need periodic attention to their valve clearances, but it is usually very easy. Hard to start is the clue.

Also, it you have a diaphragm fuel pump, E10 fuel makes the rubber stiff, and they often need replacement every few years.

People bring up the plastic cam gear in Kaw, but the truth is the average failure was in the 800-1200 hr range.

 

[Runner]

While we're talking about onerous manual requirements, the Kawi F730V manual also says to let it warm up 3 to 5 minutes before placing the engine under load. Seem excessive?

 

[MountainBuck]

The Ventrac I own has a Kawasaki V in it and it definitely needed valve adjustment at 300 hours.

I did a compression test on it to confirm it did not need a valve lap.

 

[dfkrug]

People bring up the plastic cam gear in Kaw, but the truth is the average failure was in the 800-1200 hr range.

You have probably dealt with more of these than I have, but 800+ hours does not seem like a lot for an engine used in a vehicle. I have also seen broken Honda plastic cam gears, and also their plastic cam. There are many many consumer-grade lawn tractors with well North of 1000 hours.

For comparison, the 3-cyl 660cc Mits engine in the Toro I am working on is just shy of 5000 hours.

 

[WinterDeere]

People bring up the plastic cam gear in Kaw, but the truth is the average failure was in the 800-1200 hr range.

I'm at 1200 hours on mine now. What am I in for, and more importantly, what should I be doing about it?

A commercial mower engine failing at 1200 hours is pathetic. Many commercial guys do more than that in a single season. I would really expect this engine to go at least 2000 - 3000 hours, which at my usage and deck deterioration rate, will be the lifetime of the mower.

The Ventrac I own has a Kawasaki V in it and it definitely needed valve adjustment at 300 hours.

I did a compression test on it to confirm it did not need a valve lap.

I can do that. I suspect I can find the compression spec's in my service manual, and I assume the compression testers I have from working on cars many years ago will work okay here.

 

[MountainBuck]

I'm at 1200 hours on mine now. What am I in for, and more importantly, what should I be doing about it?

A commercial mower engine failing at 1200 hours is pathetic. Many commercial guys do more than that in a single season. I would really expect this engine to go at least 2000 - 3000 hours, which at my usage and deck deterioration rate, will be the lifetime of the mower.


I can do that. I suspect I can find the compression spec's in my service manual, and I assume the compression testers I have from working on cars many years ago will work okay here.

If it helps, I have the model FD851D Kawasaki engine and yes I used the standard compression tester.

Before I did anything my compression was at 70psi. After I completed the valve adjustment my compression was at 120psi at 310 hours.

 

[WinterDeere]

Cool. I do all my yearly OPE maintenance late December or early January, so I'll post back here with my results. It'll be interesting to see what a 17 year old 1200 hour Kawi V-twin throws up on the compression test.

I don't know how the original owner treated it, I inherited the thing with the house around 300 hours, but it's had yearly oil and filter changes ever since. I average 70 hours of mowing + up to 30 hours of towing a walnut harvester or leaf blower, on that machine each year.

 

[RandyT]

I'm at 1200 hours on mine now. What am I in for, and more importantly, what should I be doing about it?

A commercial mower engine failing at 1200 hours is pathetic. Many commercial guys do more than that in a single season. I would really expect this engine to go at least 2000 - 3000 hours, which at my usage and deck deterioration rate, will be the lifetime of the mower.


I can do that. I suspect I can find the compression spec's in my service manual, and I assume the compression testers I have from working on cars many years ago will work okay here.

If you are talking about the Kaw in the 757 that mower and engine should be new enough to have the metal cam gear. The plastic cam gear issue mainly effected the models from around 98-99 model years when they changed from plastic to metal in those engines. So the FD590V in the 325-345 series mowers and the FD620D in the 445.

 

[WinterDeere]

If you are talking about the Kaw in the 757 that mower and engine should be new enough to have the metal cam gear. The plastic cam gear issue mainly effected the models from around 89-90 model years when they changed from plastic to metal in those engines. So the FD590V in the 325-345 series mowers and the FD620D in the 445.

Good to know. Just looked this up, based on your post, and it seems they stopped using plastic cam gears in or around 1998. I think my mower was purchased new in 2007, so seemingly no chance for an overlap.

Thanks!

 

[90cummins]

Absolutely ridiculous to do anything other than check clearances & regular service if it’s running ok.

90cummins