advice on how to remove muffler

Geo-TH,In

Well-known Member
I have a 10 year old 20 hp horizontal shaft kohler. I'm going to remove heads and not looking forward to removing the muffler. The part stud sticking past the nut looks bad, rusty. Don't really see how PB blaster will do much good with rust covering most of threads. Not looking forward to twisting off studs. Muffler is in the way of using impact. So what would you recommend? Heating nuts with a torch? I was thinking of grinding off part of the stud sticking out past nut, but that might be difficult, again muffler in the way. Should I run engine and get things hot? Use welding gloves on and hope I can get them lose. Was thinking of using hammer on wrench to jar nut.

Please tell me what you would do.
 
I think I would run it and get it hot. After it rounds (and it will) I would get out the Dremil and cut the nut off. Then run a die on it to clean up the threads. If all else fails I might cry and stare at it for a week or two. Removing exhaust studs and nuts ranks right up there with burning alive or being buried alive for me.
 
Kohler used pretty good metal in those nuts and studs.

1. clean the threads you can see best you can. A wire brush made like a toothbrush works pretty well.
2. put penetrating oil on them.
3. use a box end wrench or a socket so you are pushing on all 6 sides of the nut. A 6-point works best and it is metric on a Command engine.
4. If you think you are getting to the breaking point and its still not turning, apply a bit of heat with a propane torch. Of course use your judgment if its near the fuel lines, or is greasy, a torch might not be a good idea.
 
soak it with penetrating oil. wait several days. try wrench again, turn first one way and the other , if nut will move at all, spray again, if nut moves.

if push comes to shove, take a small sharp cold chisel and bust the nut.
 
I rank removing exhaust studs it next to a colonoscopy. A real pain in the butt. Unless I cut the muffler off it going to be difficult to do anything. Muffler is very expensive too.
 
The best way I have found. Is to heat the nuts then use a six point wrench to remove them.May have to soak them before,but I have had good luck doing it this way.
 
Use a thread restorer die or a thread die on the exposed thread, heat just the nut with a oxygen-acetylene smal welding tip. Heat the nut fast to red hot then unscrew it. It's that easy. Don't use a small propane tourch.
 
If the tourch doesn't work, I may see if I can buy a gismo that splits the nut. Never used one, but it might be better than twisting off a stud in aluminum head.
 
As someone already mentioned,I generally use penetrating oil and then brush exposed threads with a stiff wire brush. One of the main causes of twisted studs is the crud that is on exposed threads and as you try to remove the nut, the crud just piles up ahead of the nut and blocks the threads. I also have used a "nut splitter" at times. I bought one years ago. Never used it much, but it sure comes in handy when you need it.
 
just curious say going to remove heads,why? removing mufflers most of the time is no big deal. just loosen and take off. do it quite often here in shop. i have yet to have to use any heat. just clean them up first and puts some kroil on and take it off i doubt you have much of issue.
 
Removing head because of excessive carbon on left head. Hoping to find a leaky head gasket or intake manifold gasket to explain why the left cylinder is running rich, black plug, and right cylinder burns cleaner, white plug.

As soon as I finish a small job, I plan to take engine apart. Already got 2 head gasket sets, with new bolts. If I don't find something wrong with intake manifold or intake gaskets, off comes the heads.
 
why don't you do leak down test first instead tearing things apart to see.you do know that some engines (twins) run richer jet on one side versus other. what the motor symptons does it make it run terrible black smoke etc.
 
Already done every test you can think of, Including a leak down. Both cylinders are same and good. Engine doesn't use oil, good compression, new platinum plugs, exchanged ignition modules, different carb. You name it I've already done it. Even experiment with e20. It time to get inside and take a look see.
 
The problem is the left cylinder makes carbon right
cylinder doesn't. Read my other response below.
 
I am not sure what this looks like so I don't know if my idea will work. Sometimes a nut can be freed up by rapping it good on a solid anvil. If you can hold a heavy piece of metal behind one side of the nut and strike the other side with a hammer or a punch and hammer often a nut will loosen. Doing this springs the nut slightly making the round hole in it slightly oval for an instant which breaks it loose and allows the penetrating oil to get in. As I said I don't know if you can use this method on this engine because access/space problems. Good luck with it. I make stainless steel studs for such if I need to replace broken studs and use stainless nuts, washers, etc. If you know someone with a lathe it isn't much trouble to cut threads on each end of a new "stud". Or a die could be used but stainless is tough to cut and you want to get the die started straight. Once the lathe is set you can make a set of studs in not much time.
 
I will be lucky to have room to get a wrench on the nut, let alone hit it with a hammer. The 20 hp kohler has one muffler for 2 cylinders. If the muffler wasn't so expensive, I would cut it off to get better access to nuts.
 

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