Kohler KT17

J

Jim Becker

Moderator
Staff member
OK, it is in a John Deere 317, but it is about the same engine Cub Cadet used.

This is a Series II engine with 135 hours. I was blowing snow and the oil filler plug blew out. It of course blew oil all over the place. It is the first time this engine did this, although the previous engine in the same tractor did it many times. I got the idea that maybe the vent tube was plugged and pressure blew the plug out. It comes out of the valve cover on the side away from the ignition points. I removed the tube, which turned out to be quite clean inside. I took the cover off and found it clean in there too. There is a little filter under the cover, it looked about like an inch square piece of a Scotch-Brite pad. I took it in hand to see how plugged it was. It didn't seem to be, but was oil saturated. When I gave it a little squeeze, it started to break up. The next thing below the filter looks like a little reed valve. It all looked clean and in order. I tried not to disturb it.

I believe this tube and the filler plug are both slightly different than on a Cub Cadet. But the function is the same. Here are the questions:

- I'm not inclined to reuse the filter. Anyone have a suggestion on replacing it? Do I even need it?
- I'm not sure if the plug blowout is random of if it is going to become a routine event. Anyone with KT17 knowledge have any wisdom to pass along?
 
Compression tests. Sounds like excessive crank case pressure.

I would replace the filter, Scotch-Brite is inexpensive.
 
If the breather tube/reed is open and moving air, the crankcase should not be building up enough pressure to blow the oil plug. Could there be an obstruction further down in the engine before the breather tube?

You might give the boys over on OnlyCubCadets a try. They may be able to help.
 
On the Cub Cadets, 782, 1710, 1810, 1811, the tractors were REALLY bad about gas leaking past the mechanical fuel pump and filling the crank case because the fuel tanks were located above the engine. It honestly was a bad design from the start, but Cub Cadets (and many other LG Tractor manufacturers) had always historically had the fuel tanks located above the engines, mostly because they utilized gravity rather than a fuel pump. Cub Cadet (and most others) "solved" this problem by moving the fuel tanks to the back of the machines, under the seat, which solved the flooding problem, but also made MUCH more sense from a safety standpoint, moving the fuel away from the heat of the engine!

So, enough history lesson, but the comment about your JD 317 engine filling with gas and causing the problem is likely not the issue, since the gas tank on the 317 is already located under the seat, below the engine intake level, and it's unlikely to flood the crank case like the earlier Cub Cadets.

The Series II engine has pressure lubrication, so the issues with the original KT-17 starving one cylinder of oil and causing the engine to blow up (giving you the notorious KT-8.5) shouldn't be an issue either.

I've owned many of these engines and one issue that is a common problem is the engines puking oil, soaking the heads, and causing excessive buildup of dust/crud, causing the engine cylinders to overheat. The tinwork on the engine is designed to pull air from underneath and rear of the engine and blow it forward. This typically means that during mowing season, grass and dust is pulled up from under the tractor and blown through the engine, where it packs all of the fins on the heads full of crud. This in turn causes the rings to wear prematurely, valves to burn, head gaskets t blow, etc., any one of which could contribute to the issue you've seen.

I'd clean the engine really good, replace the filter and cover, check your compression and see if there are any other symptoms of problems. It shouldn't be building up pressure in the crank case, so something isn't right.
 
Here is a status report.

Following indy61's link, I see the filter material is even the color of the most common Scotch-Brite pads. I question whether using a hunk of Scotch-Brite is a good idea. Since I can't run down to the Kohler dealer right now, I will probably put the original back in.

Crankcase is not overfull, nor is there any gasoline smell.

I ran a compression test. The engine was cold and has not been run in a couple weeks. On 3 tries, the left cylinder read 99, 95, 95. The right read 88, 87, 85. It wasn't until later I realized each reading was equal or less than the previous reading. I should have retried the left after doing the right. I didn't hear any difference in cranking speed, but wonder if it was gradually turning slower with each try. At any rate, the book says 90 with no more than 15% variation between cylinders. Although marginal, I think my readings show adequate compression.

I have the side shields (part of the tractor) off but have not yet touched any of the Kohler tinwork. I will probably try to open up enough to see if it is worthwhile to pull more off and clean it.

The filler plug itself has a rubber plug portion that is made of rubber. I wonder how much the rubber has hardened and lost its grip on the filler tube allowing it to wiggle its way out. Maybe that is the whole problem.

The service manual suggests an exhaust restriction as a possible source of crankcase pressure. I know the muffler was reused when this engine was installed and is probably the original. I wonder if I should remove it and try to see if it is clogged.
 
Jim Becker":zawaz4i9 said:
The filler plug itself has a rubber plug portion that is made of rubber. I wonder how much the rubber has hardened and lost its grip on the filler tube allowing it to wiggle its way out. Maybe that is the whole problem.
Click to expand...

https://www.wfmachines.com/forums/showt ... ll-cap-out

I think you may be right. The filler on my KT17 II looks like this.

s-l1600.jpg


KT17_II-24302_WW_9.gif
 
Time for the update. My filler plug is the style of #7. Thinking back, I believe that I needed to buy a replacement plug for the previous engine. The original was either lost or broken. The dealer didn't have a new one but he scrounged up a used one. He made some comment about selling a lot of them. That should have been a clue. I followed Indy61's wfmachines link and saw a whole lot of discussion about them blowing out. Clearly the things just like to pop out without any underlying engine issue. I took the approach of wrapping some wire around the filler neck and bringing it up where I can wire the plug in place. I put the valve cover back on, reusing the original filter screen. I picked off any screen pieces that seemed loose. I declared the compression readings normal.

I decided to pull the two big sheet metal pieces on the sides of the engine to see how plugged up the cooling fins were. Boy they make them hard to get off. The bottom screw on each side is down inside the tractor frame. You almost need to pull the engine to get it out. There was some stuff on there, but all considered not that much. After finishing this and getting it all buttoned up again, I did one more round of degreasing (OK, deoiling). I finished this yesterday.

Today I mounted a tiller and put it to work. Everything seems to be working normally. That wasn't much of a surprise, as it seemed to be working OK when the plug blew out in the first place.
 
So far, so good. Hope it continues to work for you.

Have the same engine in my CC 782. Yes, those tins are a bear to remove-I have to pull the engine just to get them off. Did that last week to remove the starter. The retainer clip broke and the bendix gear had no way to retract, so it lodged in the flywheel gear.

I’ve heard those tins need to be removed at the end of each mowing season for cleaning.
 
I once had a starter quit working. It turned out that enough grass had found its way around the Bendix to keep it from working. I had to pull the starter to clean it out.
 
I experienced the same condition on two different kt 17 engines in two different JD 317's and changed to a pipe and cap to secure the system.
John K
 
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