Cylinder head removal CH18S

[Steve G]

Hello everyone.

Cub has started smoking a bit of late and I am going to do a leak-down test soon when I get a break in the action 'round here. Engine is a Kohler Command CH18S. I suspect the head gasket on number 1 (and perhaps number 2 as well) needs replacement. I'll know after I do the test of course. Likely it is that or a valve issue, either way requiring removal of one or both heads. Never been down that road, and seems straightforward, but one issue is bugging me and I would like to get clear on that before diving in.

I've watched many a video but remain unclear on the intake manifold disconnection. Does the full intake manifold, carb etc. have to be removed to get the head off, or can I just disconnect it at the entry to the head? Appears removal of the entire thing would mean removing an additional shroud and dealing with some hard-to-get-to bolts. Hoping to keep things simple here, removing as little as possible. Normally I would just take it to the shop, but hate to be without it for six weeks or thereabouts at the beginning of summer with sevral acres to keep mowed, plus I would have to haul it over there and bring it back, and it would have it sit out in the weather awaiting its turn in the shop.
Can anyone provide clarification?


Thanks, Steve

 

[oldnslo]

Not sure if 18 and 20 are he same but on the CH20 I had to remove the intake to get the heads off. Do not remember if was because studs holding intake on or metal to metal interference though.

 

[Steve G]

That's helpful and much appreciated.

 

[tomplum]

Getting oil fowling on the plug? If you go that route, best to do gasket sets on both sides, breather gasket and be sure to check or replace the reed.

 

[RandyT]

Not sure if 18 and 20 are he same but on the CH20 I had to remove the intake to get the heads off. Do not remember if was because studs holding intake on or metal to metal interference though.

The 18-20-22 hp used the same block. The 18 uses a throttle plate limiter screw in the carb which isn't used on the 20. And the 22 uses spark advance.

 

[Steve G]

I do have oil fouling. Good point on replacing breather gasket and reed, and both head gaskets while I'm in there.

Having checked the service manual at this point, pretty clear intake manifold would have to be removed. Not an issue really provided (2) I can access all bolts with a socket (on the one video I have seen that shows the manifold removal process there was a very tight clearance on one of the bolts to the no. 2 cylinder head, such that a socket wouldn't even fit over the bolt), and (2) no bolts are seized so bad I can't loosen them after using penetrating oil as needed. Those are my biggest reservations. Plus removing the shroud is a pain - some screws are very hard to get to on my machine and my old body rebels against laying on the floor and contorting to reach some of them. Done it before, though, when I replaced the coils a couple of years ago. Not planning to pull the engine.

May post more questions when I get around to doing this (assuming I do it myself). All input much appreciated.

I'll do what's necessary at any rate. These old machines are far superior to anything new out there of comparable size I have seen. They are just old and out of warranty, like me, and need attention on occasion.

 

[5030]

Far as I'm concerned, Kohler hasn't made a good engine since the K series. Have one on my gas welder and it's flawless and I love the sound it makes when it is ticking over.

 

[tomplum]

Far as I'm concerned, Kohler hasn't made a good engine since the K series. Have one on my gas welder and it's flawless and I love the sound it makes when it is ticking over.

When engines were knarly and sounded like power. True. Lots of love for the Commands though. A bit over engineered at times...

 

[Steve G]

I ordered gaskets kits today. Unfortunately, the new-design beefed up gasket (24 841-04-S) apparently is intended to fit only the 25HP and larger commands. No beefier gasket available for the CH-18S.

Have any of you tried using the new-design gasket on a CH-18 (or a CV-18) Command? Looks like it would fit anyway. Just wondering. Could be worth a shot if passages and bolt holes are the same and it's just a matter of trimming the outside edge.

 

[tomplum]

The bore is 6 mm larger on the 25. I work on a lot more CV's than CH's. Less head gaskets every year as there are less around, but every CV or CH that I've done had the fire ring in the last decade or whenever they changed.
The nice thing with the Kohler kits is everything that you need including the torque instructions should be in there. The breather covers gaskets I change because 1) I'm there and 2) they have been revised many times.