Mounting help for Mercury 60/40 Jet

[CaveEagle225]

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.

 

[maintenanceguy]

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.

 

[JL8Jeff]

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.

 

[CaveEagle225]

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.

 

[maintenanceguy]

You may be right. I've owned a 40ph mercury that had clamps. I don't know what a 40/60 would have.

 

[JL8Jeff]

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.

 

[MrGiggles]

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.

 

[turbotodd]

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.