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Re: 108 In Need Of Rescue

Tue Oct 25, 2011 7:03 pm

Put tractor in gear and bump the starter. If tractor moves then, my guess is the loss of compression is due to a valve stuck open, probably the exhaust valve. Note: A bit of caution, tractor will lurch either forward or backward. Also make sure the PTO clutch is disengaged.

I would pull the engine, put on bench, and do a complete rebuild.

Is there some sort of centrifical clutch pulley that is not engaginging the engine?
No, the pulley on the front of the engine is supposed to be solidly fixed to the crankshaft.

Re: 108 In Need Of Rescue

Wed Oct 26, 2011 11:42 am

Keep in mind that the 108 has a Kohler engine with automatic compression release. This keeps the valves open until the flywheel is spinning fast enough, this way the starter/generator can crank the engine faster and make it easier to start. Also, the spark plug is typically not centered in the piston. It's actually almost over the wall of the cylinder, between the valves and the piston, but it is closer to the piston than the valves. You can put a long, thin screwdriver down in the spark plug hole and into the cylinder, but you should turn the crank by hand, NOT with the starter. If the screwdriver doesn't move, she's got a broken connecting rod.

If you tear into it, get it on a bench and pull the oil pan. If the rod is broken, there will be pieces in the oil pan. Look closely up at the bottom of the cylinder bore. Typically when a rod breaks, it punches a chunk out of the bottom of the cylinder bore. If that's the case, the engine's junk. Some people will rebuild them, but you've got about a 50/50 chance of it blowing up again after the rebuild.

Re: 108 In Need Of Rescue

Wed Oct 26, 2011 1:52 pm

That is certainly good news to hear! Knowing nothing about these engines I was happy to learn about a compression release feature. I snaked a piece of copper wire down and around and was able to feel the piston move. Maybe it won't be such a big job getting this thing running after all? Thanks so much for the info gitractorman.

Re: 108 In Need Of Rescue

Wed Oct 26, 2011 4:33 pm

Look down the sparkplug hole to see if the piston is going up and down first. If it doesn't pull the engine. If it does I would pull the head and you probably have a stuck open exhaust valve. You need to pull the head anyway to clean the carbon from around the exhaust valve and replace the headgasket anyway. Like i said before i replaced the headgasket on every cadet i purchased so far they all were blown out.

Pull the ign cover and clean the points, clean the carb by removing the fuel bowel, drain and wash out the gas tank if there is old gas in it too, then start it up and if it does run good i would put seafoam in the gas and change the crankcase oil and add seafoam to the crankcase oil too.

The black paint job is no problem. With the winter approaching us its time to get it running first to make sure it runs and drives ok then disassemble it as much as you can and start wire brushing all the sheetmetal and get it ready to paint cadet yellow.

I never trust anyone when they said they had it running or it ran. The last guy here told me that the cadet 1000 had a broken connecting rod and a blown clutch so i knew he never fired it up. He took it on a trade in for another lawn mower. I never take any word, but to make up for me taking a loss i haggle it even lower in the purchasing process just incase its a parts tractor. After all if its a non runner than its a parts tractor till i get it running.

Re: 108 In Need Of Rescue

Thu Oct 27, 2011 7:29 pm

So far I have not figured out how to get 12 volts from the battery to the starter. When I put a jumper directly to the starter terminals it spins. But from the battery cables under the seat there is a lost connection somewhere. I've cleaned up the ground connection for the negative battery cable and the contacts at the voltage regulator, the coil and the starter itself. What do I check next - the ignition switch? This Cadet has sat out in the weather for a long tme. The seat was left up so the the regulator was directly exposed to the rain for who knows how long. Could a bad regulator interfere with the starter circuit?


I did mangage to push her up under a tin shed roof out of the direct weather at least.

Re: 108 In Need Of Rescue

Thu Oct 27, 2011 9:05 pm

Solenoid under the dash. Also there is a clutch safety switch under the tractor. Usually the clutch safety switch is the problem.

Re: 108 In Need Of Rescue

Thu Oct 27, 2011 9:29 pm


Does this help?


Re: 108 In Need Of Rescue

Fri Oct 28, 2011 9:39 am

It did turn out to be the safety switch at the clutch. I just pushed the clutch in and it turns right over. I would not have thought to check for that because I thought safety switches were a later nuisance development. Rudi, thanks for the schematic. It lays it all out perfectly. I don't see that particular diagram in the Kohler manual ou sent me (all 147 pages of it!) Thank you all for all the help. I'll probably need a stronger battery to spin it fast enough and I will undoubtadly have to take the carb apart and clean it before it will start and run...

Re: 108 In Need Of Rescue

Fri Oct 28, 2011 9:54 am

When trying the starter only take off the belt and run jumper cables directly to the starter terminal the largest cable is the positive one and ground the other. This will allow the starter to fly at a higher rpm cleaning the armature so it will have more torque when you crank the engine over. I have also bypassed the ignition system this way to fire them up. I run one jumper wire to the ign coil too.
I just want to hear it run asap then i know where i stand with it. If she runs then i take it apart and clean every electrical connection there is. There is also a switch on the PTO engagement lever too.

One quick check on the headgasket is too look at the seam on the left side and the front. You will see carbon or oil seeping out of the seam where the headgasket is. Seeing this tells me the headgasket is blown and everytime its been right.

Re: 108 In Need Of Rescue

Sat Oct 29, 2011 8:47 pm

Well, I wish I could get her started in time for her 40th birthday but...

I took your advice Bill and spun the starter for a minute or two with no load. Now the engine turns over with the ignition key.
Next I had no spark at the plug until I lightly took an ignition file to the points a swipe or two. Now it fires hot enough.
Then I removed the carburator and cleaned it best I could short of having cleaner to soak it in. I'm sure it'll probably need to be soaked.
Which leads me to the gas tank:
...It is probably more full of old varnish and sludge than actual rust. It had about 1 1/2 gallons of old gas sitting in it for who knows how many years. The gas cap seals so well it kept it from evaporating I guess and the gas line out the bottom was so plugged up the old gas couldn't leak out. So the inside of the tank is a mess!

I've just been reading about soap and water and sheet metal screws and muratic acid and that all sounds so futile, at least in a baffeled tank, that I looked up an on-line parts place that wanted way more for a new replacement tank than the tractor cost! Is it really possible to successfully clean the inside of a gas tank like this?

Re: 108 In Need Of Rescue

Sat Oct 29, 2011 9:58 pm


The simple answer is yes. I have already cleaned two small steel gas tanks quite successfully with my electrolysis tanks. You simply attach the tank to the negative side of the tank and the positive to the re-bar and turn on the charger. It will clean that tank rather nicely. It will require a number of rinses to ensure the oxidation all comes off.

I am not a real fan of bb's, rocks, nuts, bolts, tying the tank to a rear wheel and spinning it for a while.. I like the ease of electrolysis. No muss, no fuss no bother. Turn it on and forget it for a day or so... then rinse. :lol:

Check the links below:

CBoK - In The Library wrote:
    All About Electrolysis

  1. How To Understand Electrolysis In A Nutshell
  2. What Is The Best Voltage To Use For Electrolysis?
  3. How To Find TSP In The US And What Charger to Use?
  4. How To Build Kodiak's 5 Gallon Electrolysis Tank
  5. How To Build Rudi's 55 US Gallon Electrolysis Tank
  6. How To Build Corky's Home Brew Electrolysis Tank

Re: 108 In Need Of Rescue

Sun Oct 30, 2011 7:57 am

Pour out what you can from the tank and fill it with paint thinner or lacquer thinner and let it soak. you may have to dump it and refill it several times but it should clean up.

Re: 108 In Need Of Rescue

Tue Nov 01, 2011 2:56 pm

I gotter running today!!! I ended up cleaning out the tank with muriatic acid. It didn't look rusted up enough to merit electolysis but way too gunked up for paint thinner. I worked and worked on getting all the crap out of the carburater. And with a new battery it has started right up several times in a row this afternoon. The engine sounds real healthy too and doesn't seem to smoke at all. Next I have to figure out how to get the clutch working. It's hung up and does not disengage. I learned this by sitting on the tractor with it running for the first time while ago and even with the clutch pedal pushed down the gears would grind trying to get it in gear. I accidently shoved it into 3rd gear and off I went for a wild ride around the yard with the only way of stopping turning off the ignition. But my very next step needs to be changing the oil. Only one small problem with that...I'm too stupid to find the drain plug!

Re: 108 In Need Of Rescue

Tue Nov 01, 2011 3:52 pm

You almost have to drop the mower deck and mule drive / hanger assembly from the tractor to access the oil drain plug. It is directly above the steel plate on the hanger assembly. Take those off and you'll see it.

The driveline is easy to disassemble. Take the tunnel cover off (white cover just below the gear shifter). Once you have that open, you can see how to pull the drive shaft and clutch apart. It's not complicated, and it's easier to take it apart than to pry on things and try to get the clutch to free up.

Re: 108 In Need Of Rescue

Tue Nov 01, 2011 6:57 pm

That sounded like way too much work until I saw how easily the deck drops down with two spring loaded pins. The hanger assembly only took a couple pieces of baling wire to remove and then there was that steel (skid?) plate to unscrew. So now it has a fresh change of oil.
Tomorrow it's the tunnel cover then. Meanwhile is this the 42" deck? At least that's what it measures from tip to tip of the outer blades?


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