Case 224 runs with very little power.

jimmyboy47 said:

The engine is the original Kohler and it runs well without much smoke. It is running on the original 20 hydraulic oil for summer use only. It has a 30" (or so) stock tiller. When I go up a moderately steep hill the 224 barely can climb it even with all control valve power directed to the tractor drive motor by the travel valve. When I try to till, the tractor cann;t propel itself while tilling. It either tills in place or slowly moves forward while the tiller lacks the power to do any tilling at all. I need guidance in diagnosing if this is a hydraulic pump problem or wheel drive motor problem. Also, will an adjustment of the control valve pressure relief valve help? I have a hydraulic gauge and hydraulic line I can hook up to the drain plug hole for pressure diagnosis. Any help in determining if the problem is pressure relief adjustment, hydraulic pump, or wheel drive motor will be appreciated. I am switching to 15-40 weight oil soon. The serial no. is 9691377. Thanks in advance for any help you can give me.

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So yours is a 1974 model and assuming it is mostly original then most likely your pressure relief has failed (assuming you are not having problems with power to the tiller) Here is where it can get tricky. Most of the time the main valve body relief spring fails (wear our or actually breaks) But around that vintage the main relief also had a threaded seat in the valve body that also cracks or breaks. What you need to do is install a pressure gauge, butt the tractor up against an immovable object, place in high range and move the travel valve. You will see a rise in pressure to a point where you (should see a very slight drop or gauge needle vibration) This is the "cracking" pressure of the relief valve. The full open is typically 50 to 100 PSI above that. Now I forget what the actual relief setting is (I think 2600 psi) so check the service manual data in the archives. Yours should have the ROSS can style drive motor and those can handle a fair amount of higher pressure. I can also tell you that a relief setting 500 psi low makes a huge difference..

As for adjusting the relief valve, that depends on what style of travel valve you have. There are many different styles and for the most part are directly interchange. Make sure to compare the valve body to get the correct adjustment procedure. For the ones that use the closed end cap nut make sure you have fresh copper sealing washers that seal the nut to the valve body.

jimmyboy47 said:

Thanks for the help. The engine isn't bogging down at all and runs while the tiller and or axle motor just barely turn forward. The oil is old and I'm sure 20 wgt. My plan of attack is to change the oil and even tho I bought 15-40w I'm thinking that I'll use 20-50 instead because of it's age. I'll drain the old oil, insert my pressure gauge into the system, refill the system and check the pressure. Then adjust (if needed) the relief valve. Hopefully that will fix it and I won't have to replace the hydraulic pump. One question. When I remove the pressure gauge form the valve, will much oil come out when a I reinstall the drain plug? An tricks about draining? Also, about how how many qts./gal. does an old 224 with tiller require for a change? Thanks all in advance!

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Drain and refill procedure, my way

Since yours has the hydraulic tank in front of the engine I suggest having 3 to 4 gallons available for a fairly complete change over.
The best procedure in your "CASE' (pun intended) is with the tiller attached and raised fully. I am going to assume you are using a sleeve hitch and not a 3 point (slightly different procedure with one additional step when using a 3 point)

On the bottom of the travel valve you will find a small threaded pipe plug (usually with an allen socket) Typically this is on the bottom - towards front left (driver front in car terms) This is also where you will install a pressure gauge when testing. This plug placement in case you are wondering is between the hydraulic PTO valve and the travel/lift valve so it is not used when setting the hydraulic PTO relief valve.
Anyway, remove this plug and allow the system to drain. It does make it easier and faster if the oil is a bit warm. Make sure to remove the tank cap to speed up the process. One it has drained down, engage the hydraulic PTO and attempt to turn the tiller tines. This will remove some of the oil still in the tiller and lines. The next step is to lower the lift (gravity) once the tiller is lowered and assuming you have a sleeve hitch you can crank the engine over (disable the ignition by removing the plug wire and ground it) This will assist in draining most of the remaining oil. If you have a 3 point, while the lift lever is in the lower position, push down on the belly lift arm to drain out the oil still in the belly lift cylinder then do the engine crank. If desired, you can leave the drain open overnight and allow the system to drip out.

Inspect the tank for a loose baffle in the bottom. It is common for it to break loose and cover the supply port to the pump. If you find a loose baffle, you will need to get it repaired. This is not difficult for some one experienced in soldering tanks together (radiator shop) I personally have done my own over the years.

This is a great time to replace any hoses you feel suspect.

Get familiar with your travel valve, clean it (amazing how much grime builds up over the years)

Here is the parts manual for your tractor

https://www.casecoltingersoll.com/d..., 224, 444 Parts Manual A1278_watermarked.pdf

Here is the valve manual that should cover your tractor


But just in case, here is the general service manual section


As for oil loss when switching out the gauge for the plug, cold is better and the amount lost depends on how fast you are lol. Hint, remove the tank cap and plug the tank filler opening, this will reduce the speed at which it drains.

Thanks all for your help! OK, now the fun begins. So.., I drained the system by the plug on the valve that's under the machine (main valve?). No more than 1 3/4 gal. of fluid came out. The tank was drained empty. I had the battery charger attached, so I ran (at maybe 10-15 second intervals) the system by the key and purged a bit more oil out. It drained overnight and I repeated the process. I've filled the oil reservoir with new 20-50 to about 1" from the rim, used the key to crank the system and operated (in N) the main drive lever (name?) back and forth. Then started the engine at low rpm repeated the various manipulations of the system. Soon, it was ready to move. I put it in low and drove around for about 3 minutes. The oil level only went down an 1" in level. I did another 5 minute round. It ran much improved in low but still would not climb much of a grade in H. With the control forward L worked well. I did about 20' of tilling and it was MUCH better. I could till in reverse while going forward, which was not possible previously. As the system warmed up, the power seemed a bit reduced (viscosity?). I watched the pressure gauge as I did various things. In H going up hill, it just stopped and the pressure held at 900 psi. When tilling in low with the control valve lever in mid postion, it ran around 550 psi. The oil level never went much below the initial 1" drop. So I think this data should be helpful. I have a couple of questions. Why did it take so little oil? I was ready for 2 gals. or more. Is there much oil stored in wheel drive motor? Maybe it didn't get purged even tho I drained the system by putting the axle in N and and moving thru the main speed lever both ways several times. During that, I also used the valve that directs power to the tiller and ran thru various combinations to help drain the system. Second question, what should the pressure gauge be reading if the system were properly operating? Last, if a spring is needed for repairing the relief valve, is it available? Affordable? At this point I'm shaking this down and want to confirm that it's worthy of deeper repairs, so I'm willing to do some tinkering even tho I may soon just bite the bullet and sink more money into it.

jimmyboy47 said:

Thanks all for your help! OK, now the fun begins. Second question, what should the pressure gauge be reading if the system were properly operating? Last, if a spring is needed for repairing the relief valve, is it available? Affordable? At this point I'm shaking this down and want to confirm that it's worthy of deeper repairs, so I'm willing to do some tinkering even tho I may soon just bite the bullet and sink more money into it.

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I am going to assume you have a hydraulic PTO (oddly enough I have seen a few tractors without a hydraulic PTO where the lines are looped when not needed) So if you can tap into the PTO circuit with a gauge (just 1 fitting for the quick connect with a gauge attached works) and engage the PTO you should see pressure around 2200 PSI at operating temperature, at full throttle. The PTO is usually set about 100 PSI above the travel valve relief setting so check you service manual information to confirm. If you are not seeing anything close to this then based on your previous information about operation I would suspect the pump has worn out. BTW, did you inspect the tank for a loose baffle or anything blocking the line??

As for capacity, I usually have these completely apart doing a rebuild. I just double checked and for a typical fluid exchange it takes about 8 quarts (your mileage may vary lol) The pump produces (should) approximately 8 ish gallons per minute at full throttle. The current replacement pump kit is C43925 which is about $600+ and includes everything to install. The hydraulic settings are as follows, PTO 2100-2200 PSI, travel valve 2000-2100 PSI, lift 500-600 (575 ideal) The pump displacement if memory serves me correctly is 0.61 to 0.66 Cu.In. per 1 rotation (around 8.5 GPM at 3600 RPM) Rotation is CCW on engine, CW when looking at pump shaft. (your pump will be a CW rotation) As memory serves me the Kohler tractors us an "A" mount and Onans use an "AA" mount. (how to identify pump mount - Surplus Center )

Typically I go to surpluscenter.com for pumps and other things. You just need to take time to match up what you are needing. They are very helpfull. If you go with an aftermarket pump from some one like Surpluss Center or Princess Auto etc. It pays to get a rebuild kit (when available) Typically when I go aftermarket I disassemble the pump, put the main body in my milling machine and perform surgery to take the OEM inlet hose nipple and outlet port size. I could go into lots of detail here but that would take volumes.

When I did my 646 (which was stolen in 2010 and never has shown up) I did a slightly larger displacement pump (Briggs V-Twin upgrade) so I could maximize efficiency ( Larger feed hose/line from tank to pump etc)

Should I try to adjust the pressure relief valve first? If so, is it done while the machine runs or, as I would probably do, adjust it off and then start the system and test. My gauge is tapped into the valve drain plug with a long hydraulic line so I can observe different pressures while testing different system features. In H, going up a moderately steep grade, the machine just halted with all power going to the travel valve, the gauge stayed pretty steady at 900 psi. The engine ran at the usual rpm's. So, it seems I'd have to raise the Pressure relief valve about 1200 psi. Would this translate into many turns (clockwise) to achieve? Any guestimate as to how many lbs. of psi a turn would achieve. Many thanks for your info. on replacing the pump which I'll certainly do but I'd sure like to establish that it really needs to be replaced. The drained oil looked remarkably clean, BTW.

Round 2 of Testing: First, I turned relief valve adjustment screw in 3/8" of a turn. The pressure at which travel stopped was 950 psi. When I tried the same hill in reverse, the pressure read the same 950 and the tractor stopped at the same point on the hill. I turned it in another 1/2 turn. This a total of 7/8 of a turn and very little difference in pressure or performance. I'll add that on THIS test the machine was thoroughly warmed up whereas the first test was definitely warm but not nearly as warm as the second. Should I get more aggressive with a full turn on the screw and test again? Or, other suggestions??
Other observations: When the tractor stopped moving and the pressure was 950, a noise was coming from either the drive motor or the PRV area. Also, I am adjusting the larger set screw that is under the 3/4" acorn nut. There is another set screw 5/8" acorn nut arrangement lower on the rear of valve. I have 2 spools I believe and I'd like to know if that is the adjustment for the tiller or tiller lift. One last bit of data. I feel reasonably sure that there is no more than 1.5 gal. 20-50 in the system with less than 2" of room at the top of the oil reservoir. Is there any chance that a component needs bled? Thanks in advance for any help offered.

Round 3 of testing: deadheaded the tiller (looped it's in to it's return) and turned the Pressure relief valve in another turn and a half. Readings remained at 1000 lb. Same reading in reverse. Travel valve was fuly forward. Could do nothing to stall it or even reduce the OLD engine's rpm's much. I have the 2 spool valve (later than 969xxx serial no.) with one spool going to the hydraulic lift I think. Is this enough evidence to conclude that the hydraulic pump needs replaced? I've studied this wonderfully informative site for probably 2 hrs. reading up on the hydraulic system and various hydraulic problems, behaviors, and symptoms. I AM getting to know this machine better and am game to go for replacing the pump, based on the fact that I can't get over 1000 lbs. psi after 4 full turns of the PRV screw. Only the first turn of 3/8 gave me an increase that was substantial. I'll let it sit until I get some feed back on the health or death of my pump. Thanks for any suggestions that folks have!

jimmyboy47 said:

Round 3 of testing: deadheaded the tiller (looped it's in to it's return) and turned the Pressure relief valve in another turn and a half. Readings remained at 1000 lb. Same reading in reverse. Travel valve was fuly forward. Could do nothing to stall it or even reduce the OLD engine's rpm's much. I have the 2 spool valve (later than 969xxx serial no.) with one spool going to the hydraulic lift I think. Is this enough evidence to conclude that the hydraulic pump needs replaced? I've studied this wonderfully informative site for probably 2 hrs. reading up on the hydraulic system and various hydraulic problems, behaviors, and symptoms. I AM getting to know this machine better and am game to go for replacing the pump, based on the fact that I can't get over 1000 lbs. psi after 4 full turns of the PRV screw. Only the first turn of 3/8 gave me an increase that was substantial. I'll let it sit until I get some feed back on the health or death of my pump. Thanks for any suggestions that folks have!

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I am going to say the pump is dead. The likelihood of the PTO relief being out of adjustment and the travel valve being out of adjustment at the same time is unlikely. When you deadhead the PTO (quick connect lines disconnected) It will really load down the engine (many times it will stall it if not at full throttle) and you will hear the pump and PTO relief scream.

You need to watch how far you screw in that travel valve adjustment. The last thing you want to do is compress the relief spring fully (kills it) Also the difference in pressure verses adjustment climbs astronomically when you get close. Usually if the spring is ok it only takes 1/4 to 1/2 turn to substantially raise the pressure. Make sure you back off that travel valve relief adjustment before you attempt to test with a replacement pump as you may get a nasty surprise with mass quantities of oil everywhere including possibly places you do not want it (in your body, very very bad)

While you have it down for a pump replacement it is highly recommended to fully clean the system and go through the travel valve for spool seals, relief seat and ball inspection (replace if needed) and a new relief spring is very much recomended. If not replacing the spring, take a picture of it laid out next to a ruler and post if so we can see the condition, compression wear etc.