how to loosen BIG nuts?

[wingless]

Thanks for the additional image.

It may be that the motor mount is still acceptable for continued usage, even w/ the flaking corrosion. Clean up (on aisle 5) is required to better visualize the existing condition first.

It appears that galvanized steel lag screws and fender washers were used for attaching the mount to the stringer. The zinc on those fasteners are gone. Either replace w/ equivalent parts or clean up and recoat w/ Rustoleum Cold Galvanizing Compound if the parts are still good.

Replace any parts that have deteriorated beyond acceptable condition.

[wingless]

Here are some (formerly rusty) custom screws and studs w/ captive washers that I cleaned up w/ a utility knife blade and thread die prior to painting (threads masked from paint).

They still look great almost a decade later.

[RaymondR]

Originally Posted by SteelCruiser

Thanks for all the suggestions
.
My ignorance shows : What do I replace the engine mount ‘stuff’ with
The old /current stuff is all crumbling away
.
see picAttachment 256897

That looks like one of those mounts which can be disassembled and the elastomers replaced rather than the entire mount needing to be replaced.

[NorthCoastJoe]

A propane torch is not enough heat. Oxy-acetylene cutting torch, just don't hit the oxygen leaver while heating.

You want to heat the nuts fast only a few seconds should do it and they will come off like a hot knife through butter. Focus the heat on the nut and have a deep socket ready. It will go better if you can have a helper take the torch from you so you can get a socket on the nut quickly.

Slow heating is no good it will only heat up everything else a fast heat is best.

[Celestialsailor]

Originally Posted by NorthCoastJoe

A propane torch is not enough heat. Oxy-acetylene cutting torch, just don't hit the oxygen leaver while heating.

You want to heat the nuts fast only a few seconds should do it and they will come off like a hot knife through butter. Focus the heat on the nut and have a deep socket ready. It will go better if you can have a helper take the torch from you so you can get a socket on the nut quickly.

Slow heating is no good it will only heat up everything else a fast heat is best.

I suggested along the same lines with propane or an Oxy/Ace set-up with a small brazing tip. It allows good concentration on a large nut. And as you stated...have the impact gun loaded and ready.

[Uncle Bob]

Originally Posted by SteelCruiser

Thanks for all the suggestions
.
My ignorance shows : What do I replace the engine mount ‘stuff’ with
The old /current stuff is all crumbling away
.
see picAttachment 256897

As others have said, polyflex mounts and the good news is they can supply replacement flexible inserts in several strengths. Have been there done that and it is not that difficult. requires the engine be disconnected from the shaft and lifted, one end at a time to remove the old, clean and replace the inserts and do the other end then align the shaft and engine.

[RaymondR]

Had polymer engine mounts on my last boat and was not at all impressed with their vibration isolation capabilities or durability. Had I kept the boat I intended to replace the polymer components with pieces cut from conveyor belt.

[SteelCruiser]

Great help guys - much appreciated. The engine mounting nuts are now all removed. I have attached a chain hoist and lifted *slowly *. Completely off the mounts at front, almost off at rear. ? The unbolted coupling ‘tween gearbox and shaft? see pics …Has come apart 3/4 “ - there is 1/2” vertical separation. But I stopped with the hoist. Concerned there seems to still something deep inside & possibly still connecting? Looks like a big nut? suggestions? questions ? comments?

[wingless]

Thanks again for the images.

The large nut now visible within the shaft coupling retains the flange to the transmission output shaft.

It might be required to detach the motor mount(s) from the stringer and to remove the lower board from in front of the lower engine support to permit sliding the engine out.

[CarlF]

That mount looks old. Mounts should be replaced at 10 years. The rubber loses elasticity.

[SteelCruiser]

thanks for all the help
Engine mounts undone,
Engine lifted
Gearbox nuts undone

But the Gearbox seems stuck tight to the bell housing.
Hmmmm. Maybe I should have undone the bell housing from the motor?

Q. how / where to separate?

need to repair a burnt out clutch

[Uncle Bob]

Originally Posted by SteelCruiser

thanks for all the help
Engine mounts undone,
Engine lifted
Gearbox nuts undone

But the Gearbox seems stuck tight to the bell housing.
Hmmmm. Maybe I should have undone the bell housing from the motor?

Q. how / where to separate?

need to repair a burnt out clutchAttachment 257025Attachment 257026

With all nuts off the only thing holding it there will be friction and rust. The gearbox input shaft will have splines to the drive plate, the box itself will have a recessed section into the bell housing, not much mabee 12mm or so, a little brute force at the join may yield results.

[aqfishing]

Originally Posted by Martkimwat

Certainly would NOT do that, as it will damage the rubber mount below it and probably render them useless. Knowing how much some engine mounts can be to replace, I would do my best to not damage them unless they are already beyond redemption. There is also the very real risk of igniting the rubber with attendant toxic fumes and fire risk.

I would replace the engine mounts while you at it in any event.

Someone suggested a grinder, also a fire hazard but some wet rags to catch sparks will help. Heating carefully also good. If you must grind then just slice it through the middle from the top down.