Mounting help for Mercury 60/40 Jet

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CaveEagle225

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I am going on a road trip to pick up a used Mercury 40hp Jet Motor. I would like to at least temporarily mount it to my boat to test run and for the ride home.

Does anyone know where I can find a mounting template for a Mercury 60/40 motor?

Also, does anyone know what size bolts I should bring with me? I think 1/2” fine thread with Nylock nuts. The transom is 2” thick. The old motor was held on with 4” long coarse thread bolts, so I would like some new hardware.

I am expecting to pull the motor back off to seal up the old holes.. so this is really just to get it running and get it home.

Thanks.
 
For the test, you can just tighten the transom clamps to mount it temporarily. I would definately bolt it but I wouldn't worry about it until I got it home - unless you were going to tow the boat home with the outboard installed.

I mounted my 40hp outboard with 3/8 stainless bolts with oversized washers on the inside and outside.
 
I'm pretty sure my bolts are 1/2" but it looks like they are course thread. I'm not sure the thread matters but go with what you're comfortable with. I read somewhere that you should put 2 bolts in from the outside and the other 2 from the inside so I did that. I ended up mounting mine about 2-1/2" above the transom since my boat has a jet tunnel so you'll need to experiment and see how the spray is before getting the final height and sealing it up.
 

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maintenanceguy said:
For the test, you can just tighten the transom clamps to mount it temporarily. I would definately bolt it but I wouldn't worry about it until I got it home - unless you were going to tow the boat home with the outboard installed.

I mounted my 40hp outboard with 3/8 stainless bolts with oversized washers on the inside and outside.

Does a Mercury 60/40;Jet have clamps on the top of the mount. I know my 2stroke 25hp did, but for some reason I thought the larger motors were held on with 4 bolts.
 
I think the bolt pattern is pretty standard. My boat had a 40 hp Evinrude prop motor on it when I bought it and I changed to the Merc jet and used the same bolt holes. So if your transom already has holes drilled, you'll probably be fine.
 
The older Mercs (not sure when they quit) with twin cylinder tilt/trim did not have the standard bolt pattern. They also had clamps in addition to 6 bolts, IIRC. My 84 60hp Merc was this way, when I mounted a newer Suzuki (with the standard 4 bolt pattern) I had to redrill all new holes.

Stainless steel fine thread bolts are preferable, they are less likely to loosen from vibration. Use anti-sieze to prevent the threads from galling, and do not use power tools on them. 1/2" is the standard size, but the older Mercs like I mentioned above use different sizes. Steel bolts will rust, guaranteed. Use the biggest, thickest, fender washers you can find on the inside, especially if it's going right against wood.

I went on Ebay and bought all the hardware I needed, that stuff is pretty spendy from Ace Hardware and the like.

When I mounted mine, I set the motor on the transom where it needed to be, and just barely drilled into the transom, enough to make a mark, then removed the motor and drilled them the rest of the way. There was not enough room to drill them straight with the motor installed. A center punch would work just as well.
 
Most of the 40's use standard BIA 4 bolt mounting. SS fine thread is what I see a lot of, however Mercury sends coarse thread 1/2" SS bolts with theirs. I do like the fact that Mercury uses locking nuts but sometimes they won't come back off. Never had a problem with yamaha's double-nut/fine thread setup. Just takes longer to assemble. You don't have to torque any of them very tight, IIRC 40 lb-ft. Dont seem like much but it's easy to crush a transom.
 

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