860 Compression Test

This is my first compression test so I wanted to run the findings by you more knowledgeable individuals.

For starters, I was not able to run the engine to get it up to operating temp before completing the test. I have a no spark issue at the plugs that I need to troubleshoot.

I ran the test with all plugs out and the coil disconnected from the distributor. The first numbers in cylinder order are 74 52 63 82. I then poured a little SAE30 in the spark plug holes and turn the engine with the starter for a few revolutions. The next numbers in cylinder order are 185 145 180 140.

Based on what I have read on here the 180 numbers seem extremely high. Also, I believe this points to worn rings and an engine overhaul would be in order.

All feedback is appreciated.

Thank you in advance.
Thad

Yep! Your first numbers are really low. Since oil raised them, I'd concur with your thought on rings.

assuming both numbers correct. low dry, and higher wet point to rings.

Throttle wide open?

See how it runs before you start tearing it down for overhaul. See how it runs, how much oil it uses and what are you demands going to be put on the machine? Low compression numbers yes, but they might improve after usage and it may fill your requirements as is once it is running.

While the cold dry numbers are too low, it could be either ring / cylinder wear or, if it was sitting a long time, the rings could be sticking. They may loosen up from simply being operated at temp for a day-week or so. A faster and more aggressive way is a mix 50-50 of mineral spirits and ATF. Add a couple ounces to each cylinder and let sit for a hour to over night. Then spin the motor with the starter and repeat. Do that a few times and it will loosen up any gum that is holding the rings from moving. You will need to change the oil to get the solvent out before you run it.

You can also just add a qt of ATF and run it normally for a day or two or more.

You may have glop on the top of the valves too. Feeding water into the hot engine while at 1500+ rpm will steam clean everything. Either a squirt gun stream or a vacuum port -- don't just dump a gallon down the carb!

I tested with the throttle at about 3/4 open.

I have had this tractor for a couple of years now. End of the summer last year it started loosing power, then missing and popping out the exhaust. It had an ignition issue, so I replaced the points and coil. I also thought I might have a sticking valve. I have never noticed it burning oil. It leaks a little form the lift rod cover because I haven't had time to put the new gasket on it. I didn't get to working on it over the winter since other projects came up. About a month ago I ran a quart of ATF in the oil and a quart of ATF mixed with 3 gallons of fuel. Ran the engine for about 10 or 20 minutes and then changed out the oil.

The ignition was still having some issues, so I decided to replace the starter solenoid because the battery terminal was in pretty rough shape. After the saga of trying to find the correct part, I got it replaced and it made a huge difference on starter speed and the ignition. It would still die suddenly due to the ignition so I replaced the condenser as well. It appears to be running pretty well again.

I typically use it for mowing, but have some projects that require a little dirt work with the loader and box blade. This year I need to plow and disc about 2 acres. I think I am going to try and run it through the summer and hope to tackle any major issues next winter.

Thanks for all of the help!
Thad

Put a pint of ATF in the oil and run it for ever. It won't hurt anything and over time will free up stuck rings. Put a pint of ATF in each 5 gallons of gas you add to the tank.

Haven't seen you in a looong time.
Welcome back.