Engine Help needed

[dpregs]

Hey all,

It is that time of year again where I get an incredibly late start on getting the fleet up and running.  I knew that the engine needed some love last year, but winter is just so cold.  Anyways, I was thinking that I just needed to adjust valves, but I think I might be going deeper.  Last year I was getting lots of smoke on start up if it sat for a while and it would use oil over the season, not a lot, but enough that I would need to add it by late season.  

SO, I figured I would start with adjust valves...yeah right.  Anyways, I know how to adjust valves...usually.  When I pulled the cover I don't know how I would adjust these valves, see pic.  It looks like it is just a bolt, not an adjust nut and center bolt for tightening.  Any ideas?  What am I missing.

The next thing I did was pull the plugs.  One was dry and the other was wet with oil.  Am I looking at a teardown?  Rings?

I can't seem to find this engine on the Kohler site or anywhere.  I find CV23, but not CV23S....is there a difference.  

Engine has just shy of 1000hrs

Any and all help is greatly appreciated!!!

Edited March 28, 2022 by dpregs

[dpregs]

Of course, as soon as I post....I find this:

https://www.jackssmallengines.com/jacks-parts-lookup/manufacturer/kohler/command-pro-twin-ch-cv17-25-ch-cv620-750/cv22-23/cv23-75553-simplicity-23-hp-17-2-kw

[steve-wis]

I will be following this, I have a couple of ch18 Kohlers and have wondered  about any valve adjustment.  I haven't had a good answer yet, my guess is hydraulic lifters and no adjustment at this point.

Steve

[Bill725]

31 minutes ago, dpregs said:

Last year I was getting lots of smoke on start up if it sat for a while and it would use oil over the season, not a lot, but enough that I would need to add it by late season.  

Blue smoke is oil, black smoke is gas. The spark plug seals at the top of the threads. Oil on the threads does not necessary mean anything. What does the combustion chamber end of the plugs look like. Compare the two. The only way oil can get into the combustion chamber is: 1) past the piston rings, 2) past the valve guides and 3) the breather. If only one cylinder exhibits an issue it is either rings or valve guides isolated to that cylinder. Oil past the breather goes into the carb and the issue would be in both cylinders. If it smokes blue during start up only, most likely valve guides. With the engine cold there is more clearance between the valve guide and valve stem for oil to by pass. As the engine warms up, both the valve guide and stem thermally expand and due to different materials they expand at different rates.

I assume the Kohler Command CV (vertical) valve train is the same as the CH (horizontal). If so, the Command valve train is not adjustable because they use hydraulic lifters. I recommend using a Command Service Manual. If the rocker arms were removed from the valves, the lifters need to be removed and bled down prior to reassembly by following the procedure in the manual. You can remove the lifter without removing the cylinder heads using Kohler tool P/N 25 761 38-S. To reassemble, the rocker arm pivot screws are torqued with the rocker arm off of the valve stem. After being torqued, the rocker arm is lifted and placed over the stem of the valve.

To check the condition of the cylinders, perform a leak down test using Kohler P/N 25 761 05-S.

[PhanDad]

23 minutes ago, Bill725 said:

. I recommend using a Command Service Manual.

Available for download at the Kohler Site:

http://www.kohlerengines.com/engines/onlinecatalog/pdf/sm_24_690_07.pdf

 

[dpregs]

This is sounding like a whole new level that I might not want to get in to

[oldsarge]

HA,you started it,now ya gotta finish it!!!!!!!!!!!!!!!!!!!!!!!!!

[dpregs]

17 hours ago, oldsarge said:

HA,you started it,now ya gotta finish it!!!!!!!!!!!!!!!!!!!!!!!!!

Yeah, I think I would like to refresh the engine, but the hydraulic lifter thing to me is new.  After spending too many hours watching how to build my own leakdown tester and then realizing I don't even have time now, I ordered a leak down tester and will see what I get.  I figure it is a good tool to have along with the compression tester.  If the leakdown really shows that it needs to be done, then I will put on my big boy pants and dig in.  I really do like this machine, so I guess it is a must. 

[Bill725]

FYI, a leakdown test is made on the test cylinder on the compression stroke with: both intake and exhaust valves closed, the piston at top dead center and the crank locked so it can not rotate during the test. Compressed air is used to determine the rate of air leakage past the rings or valves. A leakdown test will not necessarily indicate a valve guide issue. But, if you have a good leakdown test on the suspect cylinder which is burning oil, it is safe to assume the oil is going past the valve guides.

[dpregs]

On 3/30/2022 at 8:17 AM, Bill725 said:

FYI, a leakdown test is made on the test cylinder on the compression stroke with: both intake and exhaust valves closed, the piston at top dead center and the crank locked so it can not rotate during the test. Compressed air is used to determine the rate of air leakage past the rings or valves. A leakdown test will not necessarily indicate a valve guide issue. But, if you have a good leakdown test on the suspect cylinder which is burning oil, it is safe to assume the oil is going past the valve guides.

Thank you for the info, plan is to do it today at some point and see what we get.  Would be great if it was just a valve seal letting oil past.  But if not, then time to learn something new.

[dpregs]

So...talking about learning something new.  I picked up a leakdown tester and gave it a go.  Not much of a go though, not sure what I am doing wrong.  I am testing it at TDC on the compression stroke, at least what I think is the compression stroke and nothing.  When I rotate the engine I get to a point where there is resistance and the piston will move on its own from the pressure, but that seems to be at bottom.  Here is a video...not sure how good it is because I just hammered it out.  Any advice is greatly appreciated.  Just learning this leakdown thing.

 

 

[PhanDad]

2 hours ago, dpregs said:

I am testing it at TDC on the compression stroke, at least what I think is the compression stroke and nothing.

I've never done a leak down test, but I'll take a shot anyway.  Somebody with more knowledge will hopefully confirm my thoughts.

From watching your video, I believe you are at TDC, but on the exhaust stroke.  Each valve moves around this TDC - the exhaust valve closes (having done it's job of venting the combustion products) and on the other side, the intake valve opens (to fill the chamber with the next fuel charge).  

At TDC on the compression stroke, neither valve should move on either side of TDC.  

So cycle the engine to the next TDC - both valves should be closed and you might hear air being expelled from the plug hole (you can definitely feel the pressure if you cover the plug hole with your finger). 

 

Edited April 6, 2022 by PhanDad
spelling

[ShaunE]

7 hours ago, dpregs said:

Any advice is greatly appreciated

What Bill said above.  You are on TDC on the Exhaust stroke.  You need to be on TDC on the Compression stroke.  And yes!  You will feel a lot of resistance.  With a Horizontal shaft engine, you can install a crankshaft clamp to keep the piston @TDC.  With the electric clutch on the shaft on the Vertical shaft engine, you will have to use that breaker bar.  It will help with another person either holding the breaker bar or listening.  At TDC on the compression stroke, you can then diagnose where the leaks are.  Dipstick hole = Rings, Carburetor = Intake valve or Intake Valve Seal, Muffler = Exhaust Valve or Exhaust Valve Seal, Head Gasket should be self explanatory.  You are looking for the source of the leak & the percentage drop in pressure between the two gauges.  OTC makes a nice tester & you did right in my opinion on purchasing one with 2 gauges.  I perform these tests in conjunction with a compression test.  With a drop in comparable compression, you will know which side to perform the leak-down on for further diagnosis.

Here is an excellent write up on Cylinder Leakage Detecting from Briggs & Stratton.

 

https://www.manualslib.com/manual/1051744/Briggs-And-Stratton-272147.html?page=24#manual

[Bill725]

11 hours ago, ShaunE said:

you will have to use that breaker bar.  It will help with another person either holding the breaker bar or listening.

Good luck with that! I have not been able to hold the crank from turning.

Edited April 7, 2022 by Bill725

[ShaunE]

1 hour ago, Bill725 said:

Good luck with that! I have not been able to hold the crank from turning.

Turn the air down or hit the gym LOL!

[dpregs]

Hey guys,

I think I got it right this time.  Looks like air is coming from carb on left cylinder and from the valve itself on the right cylinder.  The piston didn't move when I ramped up the air, but I am pretty sure I was TDC on the compression stroke.  Got a minute?  Watchy here:

https://youtu.be/vcVjjMAGulo

[Bill725]

On 4/7/2022 at 10:11 AM, ShaunE said:

Turn the air down or hit the gym LOL!

Atmospheric pressure is 14.7 PSI. A typical engine has 9:1 compression ratio. The perfect cylinder (no losses) compression pressure is 14.7*9=132 PSI. When performing a leak down test, I use 100 PSI inlet pressure. That way if the cylinder gauge reads 90 PSI there is 10% leakage/loss (100 PSI -90 PSI) If the cylinder gauge reads 85 PSI there is 15% leakage.

Edited April 10, 2022 by Bill725

[dpregs]

Hey everyone.  I appreciate all the feedback thus far.  It looks like I am going to bite the bullet and tear this down and rebuild it, but I am having a heck of a time finding a rebuild kit.  When I google CV23s it doesn't recognize it as an engine.  Are there rebuild kits out there or am I relegated to buying each piece?  Thank you for any and all help/direction/links!

[Bill725]

47 minutes ago, dpregs said:

Are there rebuild kits out there or am I relegated to buying each piece?

Pats Small Engine Plus (psep1.biz) has rebuild kits. A short block, less cylinder heads and externals is P/N 24 522 126, $903.45. A CV740 replacement engine is $1425-1677 depending on spec no. Call Medart Engine to determine correct replacement engine spec.