I have an old 7.5hp Johnson 83 model with two bolts corroded in the exhaust cover that are broken off.
The motor lost compression between the cylinders because of head gasket failure, so I have a new HG in hand, and gasket for the exhaust cover.
Unfortunately two of the bolts on the exhaust cover sheered off far easier than they should have (didn’t take much to do it). They are corroded in their space. I can’t get the bolts out now.
Originally I had a good 5/16" of bolt sticking out, so I tried heating the aluminum around them with a torch… heating the bolts themselves with a torch, and I’ve tried several different brands of penetrating oil, including the “■■■■■■■■■■■■” stuff. I used a dremel to cut a slot in them to see if a flathead screwdriver would remove them… no luck.
Basically I don’t have a lot of bolt left exposed now, no way of getting channel locks on them or anything of that sort. Any suggestions on getting them out? I am trying to avoid having to drill and tap the holes, and trying to avoid paying a machinist to extract them. I have replacement bolts from a parts motor on hand.
“Sire, it belongs in truth to the Church of God, in whose name I speak, to endure blows and not to inflict them. But it will also please your Majesty to remember that she is an anvil that has worn out many hammers.”…Theodore Beza
They make those kits where you drill out the center and then drill in the removal tool. It drills in backwards so it grabs and hopefully removes the bolt. And I always hear of people using heli coil kits to repair threads ect…, but I never have myself. Youtube is full of helpful info if you haven’t given it a try yet.
Be VERY VERY careful. If you break off the reverse bit in the hole, you’ve compounded your problem. They are made of very hard (and brittle) stuff and you will not be able to drill out the easy-out bit. You’ll be reduced to tiny tips on a dremel tool to excavate the easy-out bit… very very very tedious.
Sometimes I have luck extracting them with a nut welded to it.
Clean the top of the stud, and try to force a nut on best you can. I usually tap one on with a hammer.
Mig weld the center of the stud to the inside of the nut… like you are filling it in with a liquid.
As soon as it’s not cherry red anymore, put a wrench to it and use the heat as a helper… get it loose while the metal is still super hot.
If it breaks again, the stud is too far gone and you are going to be drilling and tapping.
I know you’ve tried penetrating oil but you might try a mixture of acetone and automatic transmission fluid. Seems to be the killer of penetrating lubricants. Before you try to put any force on the easyout, etc. I would hit with this solution just in case.
Flyvet, I hadn’t heard of the acetone/ATF combo until the other day. I have some acetone at work I can bring and try.
“Sire, it belongs in truth to the Church of God, in whose name I speak, to endure blows and not to inflict them. But it will also please your Majesty to remember that she is an anvil that has worn out many hammers.”…Theodore Beza