Kohler MV16 repair

[FixOrRepairDaily 26]

Hi. My mower died at the end of last season so now I’m going to try and fix it. It’s my first time rebuilding a lawnmower engine so I’m open to good advice. 😀

[pfrederi 17,741]

Do you know what is wrong with it???  I did an M-18 a couple years ago.  Would not do it again. Some parts are hard to come by or very $$$.  I was about $900 parts and machine shop work..would be more now...

 

After you see what you need start pricing parts and machine shop work

[pfrederi 17,741]

Welcome!!!

 

Just realized you are in Sweden.  Parts may be significant issue for you ...

 

Youu can download parts and service manual for horizontal M 18/20 here.  Very similar service procedures.

 Click on the picture to open links

 

 

EDIT::  Added MV service manual 3rd picture

 

 

 

Edited January 7, 2023 by pfrederi

[pfrederi 17,741]

Välkommen till Röda torget

[oliver2-44 9,756]

What tractor is that engine in?

of your tractor!

[FixOrRepairDaily 26]

Thanks for the kindness oliver2-44 and pfrederi. 
Last time I tried to start it gas shot out of the exhaust after a half hour of charging, priming and trying. At first I thought it was a blown head gasket until I remembered that it’s air cooled. 😆

It’s a Toro HMR1600. Here’s some pictures for you. These are some of the ones I take to study and remember how to put it back together.  I can take some of the chassis tomorrow. 👍

[oliver2-44 9,756]

Before you take it any further apart it would be good to do some checks to help determine if it really needs a full overhaul.  @pfrederi please join in on this.

Go through the manual especially the trouble shooting and overhaul sections

1. Can you rotate the engine and confirm all 4 valves are going up and down like they should. Try to look at the valve sealing surface and the valve seat surface. Do they look smooth like their sealing, or pitted or burned? (blowing gas back through the carburetor could be an indication of a leaking intake valve, or other things) 

2. Also rotate and verify both pistons are going up and down. 

3. Did you take a compression reading on the cylinders before you started disassembly?

4. Do you have the precision tools and skill to measure each cylinders diameter at the top and bottom of the bore, in 2 directions? or do you have a machine shop that could measure them for you? 

[953 nut 55,281]

What testing was done prior to the decision to take the engine apart? Compression, intake vacuum, spark.

[FixOrRepairDaily 26]

I will rotate and check today.

 

I didn’t do any testing but it sounded like it had lost some compression when I tried to start it last time. I don’t own those types of testing tools but I can measure the piston with my micrometer.

 

It did have spark because it ran twice on the gas I primed the carb with. I think I need to check the fuel system also.

 

I took it apart to give it a good cleaning and inspection. I also want to replace badly worn parts if I can find/afford new ones. It’s kind of cold and dark here in the winter so I try to do inside work like this now. Plus it’s fun to learn new things

 

I’m not a mechanic but I did do a total tear down and rebuild of my Ford 5000  back in 2020 and it’s still running so I am  pretty good at following manuals. The thread is in Swedish but you can see pictures here. https://www.maskinisten.net/viewtopic.php?f=62&t=326605
 

Edited January 8, 2023 by FixOrRepairDaily

[FixOrRepairDaily 26]

This is the patient. I bought it used about 15 years ago. 

Edited January 8, 2023 by FixOrRepairDaily

[pfrederi 17,741]

 

16 hours ago, oliver2-44 said:

Before you take it any further apart it would be good to do some checks to help determine if it really needs a full overhaul.  @pfrederi please join in on this.

Go through the manual especially the trouble shooting and overhaul sections

1. Can you rotate the engine and confirm all 4 valves are going up and down like they should. Try to look at the valve sealing surface and the valve seat surface. Do they look smooth like their sealing, or pitted or burned? (blowing gas back through the carburetor could be an indication of a leaking intake valve, or other things) 

2. Also rotate and verify both pistons are going up and down. 

3. Did you take a compression reading on the cylinders before you started disassembly?

4. Do you have the precision tools and skill to measure each cylinders diameter at the top and bottom of the bore, in 2 directions? or do you have a machine shop that could measure them for you? 

 

Definitely look at the valves.  You can lap them to improve the seal.  No new parts needed and cheap to do.  Check the valve clearance.  they are not adjustable.  If too tight you have to grind just a bit off the stem.  If they are too loose you have to replace them.  that isn't cheap and Kohler changed fro m30 to 45 degree at some point in the production run.  Too loose would not cause them to spit the way you described too tight may do that. 

 

If it didn't smoke  before this I would check the valves and put it back together.  if the cylinders are worn getting machine shop work and buying new pistons/rings (if you can find them) would not be worth the $$$

[FixOrRepairDaily 26]

I did the valves today. I guess I’ll have to check the clearance after I put the cylinders back on.
The cylinders looked pretty good but the pistons are just below spec. I’m going to check on new ones and definitely try to get new rings.
Here’s some more pictures. 

[pfrederi 17,741]

Beautiful work on the valves!!.  Hope you can find the oversize piston and rings you need. 

 

 

[FixOrRepairDaily 26]

On 1/8/2023 at 6:27 PM, pfrederi said:

Beautiful work on the valves!!.  Hope you can find the oversize piston and rings you need. 

 

 

Thanks. 👍 I’m working on finding parts now. I want to order everything at once to avoid shipping costs. It’s expensive enough as it is. 💸💸💸

[FixOrRepairDaily 26]

Question: Why is there no gasket between the cylinder and the motor? 
There’s a thick, expensive one between the cylinder and head. Is it because there’s not supposed to be any pressure there? Isn’t there pressure from the oil getting hot? Should I use a small amount of permaseal?

[pfrederi 17,741]

22 minutes ago, FixOrRepairDaily said:

Question: Why is there no gasket between the cylinder and the motor? 
There’s a thick, expensive one between the cylinder and head. Is it because there’s not supposed to be any pressure there? Isn’t there pressure from the oil getting hot? Should I use a small amount of permaseal?

 

 

Sealant per service manual.  I didn't like doing my M-18 as Everything was glued together

 

 

[FixOrRepairDaily 26]

New pistons, rings, gaskets and air cleaner ordered. I’m going to pick them up in March when I visit the US for vacation. 👍🏻
I might buy a new carburetor if I get a good deal on it. 🙏🏻

[FixOrRepairDaily 26]

Does this bearing belong in my carburetor somewhere?

After pulling out the chock arm of the carburetor, a small ball bearing about 4mm D fell out along with a spring. I found them on the floor and figured out what they are for and where to put them back. They hold the arm in place and create a force to keep it in position. I also found a bearing 2,5mm D but don’t know if it’s from this carburetor or was just on my shop floor. 

 

 

Edited February 5, 2023 by FixOrRepairDaily

[FixOrRepairDaily 26]

I can’t find it on the picture so I’m guessing it belongs to something else. 

[FixOrRepairDaily 26]

Fresh back from vacation with my parts. I got the 0.10 oversized pistons.  Everything went well and now I’m excited about putting my cutter back together. 👍🏻

[FixOrRepairDaily 26]

Ran into a speed bump. I checked the rings in the cylinder, according to 10.9.3 in my service manual, and they are too big.😳 Now I need to grind the ends down so they fit. This will be my first time for this so I will have to be careful.😢 The joy of diy. 😁

[953 nut 55,281]

11 hours ago, FixOrRepairDaily said:

Now I need to grind the ends down so they fit.

               File them by hand, cast Iron will file very easily and if you use a grinder you will go too far in a heartbeat. File a few strokes then check the fit, slow and easy.

[FixOrRepairDaily 26]

Making progress. 👍🏻

[Tuneup 1,433]

OK, I read that you got .010 pistons so, without a bore job on each cylinder, sure, those rings are going to be much too big. I'm not reading that you intend to bore the cylinder and doubt those pistons will meet their spec if they fit at all. Let us know. Harder and harder to find a shop to bore and resize in the USA, at least here in Georgia. How's about Sweden?

[FixOrRepairDaily 26]

It would not be difficult to find someone to do it for me but since it’s not a difficult job I will do it myself.

Working on cleaning still. Lots of surfaces to scrape and scrub.