Mercury Clamp Screws

[jbox84126]

Hey folks,

I have a 4HP Mercury Outboard for my dinghy (F4MH, Seriel: 0R897787). The transom clamp screws are nearly impossible to turn; the plastic levers are long gone and the screws only turn with consider force on a vice grip.

Couple questions:
1/ I bought replacement levers but I need to get the screws out to rivet them in. There doesn't seem to be a way to take the pressure plates off to remove the screws from the bracket. Is a hacksaw the only solution to get the screws out or is there something I'm missing?

2/ I can't for the life of me find true replacement screws. The part number is 8M0156642, any suggestions on where to look to find these?

3/Let's say i do find replacement screws. What are some ways to treat the socket and the screw to ensure it's relatively, easily usable long term?

[Shrew]

CRC break cleaner on the threads. Then hit is with a wire brush. Then clean it up and use some Mercury 2-4-C or similar. No need to replace them.

[Jammer]

Originally Posted by jbox84126

1/ I bought replacement levers but I need to get the screws out to rivet them in. There doesn't seem to be a way to take the pressure plates off to remove the screws from the bracket. Is a hacksaw the only solution to get the screws out or is there something I'm missing?

On Nissan/Tohatsu/Mercury, you have to take the pressure plates off by drilling or grinding the end of the bolt that sticks through the pressure plate.

Generally, what you want to do, is clean up the exposed threads as much as possible (wire brush, solvent, rag) and oil them. Use penetrating oil like JB80. Let sit, oil again. Then remove the screws, and use a tap and die to chase the threads on both the screws and the transom bracket.

Usually there's an oil hole that leads to the midpoint of the tapping. You can spray some JB80 or something into that also.


The new ones are plastic. If you want metal, there are used ones on ebay.

[jbox84126]

Originally Posted by Jammer

On Nissan/Tohatsu/Mercury, you have to take the pressure plates off by drilling or grinding the end of the bolt that sticks through the pressure plate.

Generally, what you want to do, is clean up the exposed threads as much as possible (wire brush, solvent, rag) and oil them. Use penetrating oil like JB80. Let sit, oil again. Then remove the screws, and use a tap and die to chase the threads on both the screws and the transom bracket.

Usually there's an oil hole that leads to the midpoint of the tapping. You can spray some JB80 or something into that also.


The new ones are plastic. If you want metal, there are used ones on ebay.

So is there no way to get it off without destroying the bolt? Conversely is there any way to rivet in the new lever in situ?

[Jammer]

Destroy is a strong word. They're sort of staked on, right? Depending on how fancy you want to be you can drill and tap a hole for a #8 pan-head screw in the middle of the bolt instead and use that to put them back together.