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I have a '72 140 with a Kohler K321 engine. When I had it running it would start up with no smoke. I just started to do some work on it and found the carb flange was broke so I removed the carb and then did a compression test. The compression test result was 118#. I'm not sure if the engine was ever rebuilt or not. Question is should I do a leak down test? I don't have a leak down tester so I'm not sure what to do. The leak down tester I was looking at is around $65.00. I'm planning on restoring this tractor as time permits so it's going to be a slow go. So right now I'm seeking your opinions on whether I should buy the tester and do the leak down test. TIA for your help.
 

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Yes. The Kohler uses an automatic compression release, so compression tests are inaccurate on them.

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Thanks guys for the replies. I'm going to check with my neighbor who works on race cars and see if he has a leak down tester. If he does, I know he will let me borrow it. I just want to make sure the engine is 100% before I pull it off the tractor.

Nick - I'm not sure if you remember but this is the tractor you and I sent a few emails back and forth two years ago! I thought I bought it last year but I checked my records and it was Sept of 2017. That time flew by!!
 

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Thanks guys for the replies. I'm going to check with my neighbor who works on race cars and see if he has a leak down tester. If he does, I know he will let me borrow it. I just want to make sure the engine is 100% before I pull it off the tractor.

Nick - I'm not sure if you remember but this is the tractor you and I sent a few emails back and forth two years ago! I thought I bought it last year but I checked my records and it was Sept of 2017. That time flew by!!
Oh yes I remember it well. Can't wait to see more!

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Well I didn't think it was broke until I started to look over some things a couple of weeks ago. Here is a link to the carb that was on it. I removed the carb and found the carb flange was broke. They had a wire around the bolt head and then twisted it around the inlet fitting. They also had silicone smeared all around the flange to seal it up.

https://www.mytractorforum.com/12-john-deere-forum/1335727-carb-72-140-a.html


So, while I have the carb off, and I suspect a blown head gasket, I'll do the leak down test to see exactly how healthy the engine is. If everything checks out OK, all I'll have to do is put a new carb on the engine and paint it. If I do find something wrong I'd rather do it now rather than down the road on the restore.
 

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Those carbs are not expensive. I would think about replacing the carb and do a run test. Start it up and let it run on/off over several days as a performance test.

When thinking about restoring a piece of equipment, I get it working mechanically FIRST. If I'm please with it's performance I then later apply the paint. (lipstick)

Reduces the chance of putting lipstick on a pig:tango_face_surprise.
 

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Those carbs are not expensive. I would think about replacing the carb and do a run test. Start it up and let it run on/off over several days as a performance test.

When thinking about restoring a piece of equipment, I get it working mechanically FIRST. If I'm please with it's performance I then later apply the paint. (lipstick)

Reduces the chance of putting lipstick on a pig:tango_face_surprise.

My train of thought also. :fing32:
 

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Geez, the time is flying by. Never went this fast when I was working!!! Got a few free minutes right now so I thought I would post a follow up on the leak down test I did. I got the engine at TDC on the compression stroke and then did the leak down test. I put 90psi into the head, (spark plug hole). I got air coming out the carb port and out the muffler. According to the gauges, it looks like the exhaust and intake valves will need some work. I'll check valve clearance first to make sure there are within specs. If they aren't within specs, I'll set them and do another leak down test.
 

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Piston needs to be at TDC on compression for a leak down test. How you holding the piston there at 90 psi.? Otherwise if at bottom of the stroke you have the possibility of both intake and exhaust valves being open.
 

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Cadman, You don't need a compression test or a leak down test for your Kohler...they will both tell you your engine is shot! As Nick4030 posted, the Kohler has Automatic Comnpression Release (ACR) and when below 600rpm, the exhaust valve NEVER closes completely.

What yo DO NEED is the Kohler Service Manual. This explains the ACR and how to check using a Manometer with instructions for building this simple device. Search online or go to WFMFiles.com for manual. Bob
 

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Piston needs to be at TDC on compression for a leak down test. How you holding the piston there at 90 psi.? Otherwise if at bottom of the stroke you have the possibility of both intake and exhaust valves being open.

I clamped 2 needle nose vise grips on either side of the flywheel and had them against the frame. I had it at TDC on the compression stroke and piston didn't move with 90psi.



Cadman, You don't need a compression test or a leak down test for your Kohler...they will both tell you your engine is shot! As Nick4030 posted, the Kohler has Automatic Comnpression Release (ACR) and when below 600rpm, the exhaust valve NEVER closes completely.

What yo DO NEED is the Kohler Service Manual. This explains the ACR and how to check using a Manometer with instructions for building this simple device. Search online or go to WFMFiles.com for manual. Bob



Thanks for the info and the link. The Manometer instructions mentions about opening and closing a clamp. What type of clamp are they referring to and where is it located?
 

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Cadman, I've never had a need for the manometer nor used one! I read through the process in the manual and read the comment about the clamp...and no further mention of how/why/where! I little research online and I found a comment about a valve and a manometer.

With the manometer connected to the oil fill tube and water in the manometer a clamp or valve NEEDS to be closed before starting the engine. When the engine is running, the valve or clamp can then be opened to take your reading. The valve/clamp should then be closed and the engine turned off. If the valve is not closed before shutting down, water can be sucked into crankcase.

I would think anything to close the tubing between the oil fill tube and the U-shaped manometer tube would be fine.

Sorry, but no additional info! Bob
 
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