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I've got a Kohler K91 from a lawn vac that I'm trying to bring back to life ( not do a 'restoration' -- I'm way too slow and clumsy for that ). I'm just hoping to get the lawn vac working again.
Anyway, it's really not in that bad a shape, but I have a somewhat knotty problem. Both of the exhaust manifold bolts are sheared, and my attempts to drill them out started to enlarge the holes to the side. These are badly rusted in. One still had a bolt in it when I started, and I soaked and heated it for many days -- only to have it snap with slight pressure.
I've measured things, and the exhaust opening is about 3/4". It looks like I might be able to get it threaded for some 1/2" iron pipe and rig up some kind of an exhaust. I no longer have the original manifold anyway. (This thing has been sitting for about 20 years).
My other choice would be to have someone (not me !) put in some kind of inserts. I'd still have to come up with some kind of a manifold piece, and it seems like a lot more hassle.
Any thoughts on which route to go -- or other options?
All the K series engines I've dealt with had threaded exhaust ports, I know my 301 has that and my Wisconsin has that as well.
Otherwise if you want to just wrap it up and send it out this way, I'll give it a good home....
Hey, it was worth a try. My whole collection is going earlier and earlier lately, I just picked up a Lawn Boy Gardener for too cheap to pass up.
1/2" pipe should work, taps are available but it'll be a royal pain to tap the cast iron. That stuff comes out like powder. The drill size is 23/32, it would be best to build some sort of fixture to hold the engine at a comfortable angle so you can concentrate on getting the angle right. Make sure to stuff something in there to keep chips out and clean very thoroughly afterwards as well.
You can also ask over on MTF if someone has a better way of doing it.
When you thread the nipple in, make sure you put a lock nut on it. The vibration will cause it to loosen up. Electrical locknuts are pipe threads. Good luck, and keep us posted.
It may have had the bolts originally, my K301 has the holes drilled and tapped, but an elbow threaded in for the exhaust. Different applications just did it differently I guess.
Briggs used what looks like an electric fitting lock nut on their exhausts.
If you are having a space problem you should ask for a short radius iron street elbow.
This is male on one side and the thread runs right up to the bell of the female side.
Yep, all I ever saw were threaded. Usually 1". Pick up a "pepper shaker" muffler - which also has pipe thread and spin it on - instant complete exhaust.