The bolts in this thread are lag bolts. Why the picture of a machine thread bolt on home page? Did I misunderstand post?
I installed my new motor mounts, have a question
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Not sure what you mean. Lag bolts are used to mount the isolator to the floor. If you are talking about the threaded insert image, that is an option. It has a wood screw thread on the outside and a machine bolt thread on the inside. You would use machined bolts to mount the isolator if you used them.
If you do the two part epoxy,
make sure to teflon tape the lag bolts or you mite not be able too take the bolts out at a later date if needed . twice around each bolt should do the trick.
make sure to teflon tape the lag bolts or you mite not be able too take the bolts out at a later date if needed . twice around each bolt should do the trick.
Is the stringer glass over wood? If so, it would be easier to whittle down a dowel to fit the lag profile, and then epoxy it into the stringer, cut flush with the top. If you pre-drill the end with a 3/16 drill, then the new lag will go right in and bight tight. Have done it several times over the years and works great.
What is the approximate torque for a 2.5" X 3/8" lag bolt in a mahogany engine bed? I was working on an old boat and found Lag bolts for the rear motor mounts and NC bolts for the fronts. Both seemed kind of scary. I did end up making studs out of carriage bolts for the front and bedding them in epoxy and cabosil after cleaning out the holes and treating the holes with unfilled epoxy first. West says its a good fix.
The mounts in the link you listed are very different than the ones I have on my boat. Mine are aluminum with a more substantial base for the lags. Are yours the exact replacements for the ones that were removed? Also - are the 2 rear mounts different from the 2 forward mounts? I was told that the rear mounts take more strain. Not sure if this is true - just what I have heard.
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Just out of curiosity, could you just use a little over 1/8" worth of washers on the two that wont tighten?
My old ones look like yours too. The ones in the link are for the ysm12 and use the same on all 4. I got the part number from a Yanmar parts list. Must be a new design. The new ones look to have more rubber in the isolator. They do work well. I do have concerns about them having a thin steel foot though.
We dealt with the same problem
We had the same problem on our old Hunter 336. Half the bolts for the engine mounts would just spin and the engine wouldn't hold an alignment. Here's how we fixed it. First I should mention that we lifted the engine with a chain hoist and left it suspended above the beds, which made this job a lot easier. After removing all the old mounts and thoroughly cleaning the area, I filled the holes with acetone to dilute any oil or grease that may have accumulated and which would have interfered with the next step. Then I took some Clear Penetrating Epoxy Sealer (CPES) from rotdoctor.com and filled the holes. I let this penetrate into the holes for 24 hours, and then used a syringe to suction out the excess that didn't absorb (it stays flowable for several days). I let that cure for a week, and then filled the holes with Rot Doctor's layup and laminating epoxy. After letting that cure for several days, I drilled out the holes with my hand drill, and then installed the new mounts. I used lock washers under the lag bolt heads, and had no problem getting the bolts to bite well enough to get them to tighten down enough to completely compress the washers.
The acetone dilutes any oil that may be present, the penetrating epoxy soaks into the wood around the bolt holes, and then the laminating epoxy bonds to it. If you wanted to add even more bite, you could add some sawdust to the laminating epoxy. It took some time, it was about two hours work but it was spread out over two weeks start to finish due to curing time, but nothing about it was hard and it worked really well.
Good luck.
We had the same problem on our old Hunter 336. Half the bolts for the engine mounts would just spin and the engine wouldn't hold an alignment. Here's how we fixed it. First I should mention that we lifted the engine with a chain hoist and left it suspended above the beds, which made this job a lot easier. After removing all the old mounts and thoroughly cleaning the area, I filled the holes with acetone to dilute any oil or grease that may have accumulated and which would have interfered with the next step. Then I took some Clear Penetrating Epoxy Sealer (CPES) from rotdoctor.com and filled the holes. I let this penetrate into the holes for 24 hours, and then used a syringe to suction out the excess that didn't absorb (it stays flowable for several days). I let that cure for a week, and then filled the holes with Rot Doctor's layup and laminating epoxy. After letting that cure for several days, I drilled out the holes with my hand drill, and then installed the new mounts. I used lock washers under the lag bolt heads, and had no problem getting the bolts to bite well enough to get them to tighten down enough to completely compress the washers.
The acetone dilutes any oil that may be present, the penetrating epoxy soaks into the wood around the bolt holes, and then the laminating epoxy bonds to it. If you wanted to add even more bite, you could add some sawdust to the laminating epoxy. It took some time, it was about two hours work but it was spread out over two weeks start to finish due to curing time, but nothing about it was hard and it worked really well.
Good luck.