MacGregorSailors.com

With the talk lately of transom wedges, I decided I'd add a pair and document the process. While my steps are for a Merc 60 this should apply to pretty much any motor. Please don't take this as an endorsement for them, seeing as I haven't had a chance to try them out yet.

First you will need to gather together some supplies. For the wedges I purchased these:

http://www.overtons.com/modperl/product ... Wedge_pair

You can also find them at West Marine.

You'll also need an engine hoist, a few socket wrenchs, a 19mm regular and deep socket, a 13mm socket, a razor blade and some 3M 5200:



Finally, this is something I found out half way through, you'll need two 1/2" x 4 1/2" stainless bolts with corresponding stainless locknuts for the upper mounts.



So now you have your stuff you'll have your engine that looks like this:



First remove the cover:



Next, while your boat power should be off, to be safe remove the negative ground cable witht he 13mm socket and also don't forget to remove the fuel line:



You'll notice at the top in the center of the picture above is a metal loop. That is what you'll attach your hoist to. Attach it and put just enough tension on it that the weight will be off the bolts after you loosen them.

Here's a shot with the hoist attached. It gives an idea of the max angle you can possibly get with the factory transom and Mercury 60 Bigfoot. Notice that even with the engine all the way down there is very little negative angle...no wonder the bow rides so high.



Now that your engine is safely supported you have four bolts and locknuts to remove.

The top ones are easy. You'll want to use the deep socket on the outside upper lock nut, and the regular socket on the inside:

Outside:



Inside:



The lowers are a bit more difficult unless you have a helper. I did this time, but didn't when I installed the engine. If you don't have a helper just place a wrech with a deep socket on the bolt and you should be able to jam it enough that it'll stay in place. Otherwise, just get someone to go in the boat and hold it for you. These bolts are behind the long narrow cover inside the aft section of the cabin.




Once the nuts are off the bolts, you'll find that if you engine was mounted on the lowest mounting holes you wont be able to slide it forwards because it catches on the lip, so you'll have to remove the bolts for the upper mounts as well.



Now that the engine is free, hoist it up a little to get it out of the way and you'll see some excess 5200, and other gunk.



You'll want to scrap off the excess 5200 with the razor blade and clean up the rest of the area with Acetone. You'll probalby want to wear some gloves when you do this...I'm not smart enough though...more on that later.



Now it's time for the worst part. You'll need to apply 5200 to the top bolts. These are the new 1/2 x 4 1/2 that you purchased. I firmly believe that 5200 is some sort of pigeon excrement spawned by a bird possessed by the Evil One. No matter how hard you try it will find it's way onto places that you know you did not touch, it will spread like a virus, and coat things with the alacrity normally reserved for Politicians' words in a room full special interest groups with open checkbooks. But I digress....Fortunately the almighty has provided an antidote to the 5200 and that is in the miracle that is Acetone. Have plenty on hand, and on boat, and on tools, on whatever you set the tube down on to...

Make sure to apply the 5200 liberally to the bolts. The reason for this is that the transom is reinforced with wood. Wood + Water = BAD. You don't want water to be able to get in there. I apply around the bolt then push the bolt through and rotate the bolt around to make sure it spreads out.



Once that is finished I put some more on the protruding end and spread that around:



Once the top bolts are in place you'll want to hang the transom wedges in place as shown in the following pictures:

Starborad:


Port:


Now hang your engine back on the bolts. I decided to raise the engine one hole instead of hanging it on the top most hole. This was based on the fact that I'm not getting the preformance I should be from my props.

My cavitation plate was just over an inch below the bottom of the boat on the top most hole and it is really not supposed to be more than an inch. After talking with the shop that I does my engine work, they suggested that I raise it up to see how it goes.

Once the engine is hung on the top bolts apply 5200 to the lower bolts and push them through. Make sure the wedges are in place and then it's just a matter of tightening everything back up.



Here you can see the new angle that I can get with the wedges in place. It's clear the the engine can "tuck" under the boat now.




This should finally allow me to actually trim down the motor. In the past regardless of how much down trim I put on the motor it didn't really make any difference. That goes against everything that manual says about how the boat should behave. Because of that fact and the other arguements I've seen on the board I've decided to give the wedges a try in the hopes that the up and down trim will actually trim something.


I'll report back when I have time to take it out.

excellent stuff!
after some thorough examination (X vs. M), i can now see how wedges are required on an M (vs X). i can also see that the stock transom angle appears to be noticeably less on an M vs X.

one suggestion for these heavy motors (300# and over) is to place an aluminum backing plate on the inside of the transom. i prefer both locations. the splash well and the area accessed via the rear berth.

Yours:




Suggested:



Bob T.
"DāBob"
'02X w/ '04 90-TLDI (14" x 11 pitch)
Dinghy Motor: '06 2.5-Suzuki

I haven't added a backing plate since the 60 Bigfoot is the same weight as a 50, and the 50 is what they show in all the promotional videos. Its actually the same engine just with a different ECU.

It seems if they are promoting using that engine in the videos it must at least be "OK", and that it would be designed to handle the weight. There's a very good chance I'm wrong though, seeing as I have no specs or scientific evidence to back that statement up.

I did inspect for cracks and I found that their were none, but then it has only been on the water 5 times since the initial install. I'll check again in a couple of years, and if their are any signs of wear I'll put some plates on it, it's probalby good advice.


My bigger concern is that with the wedges there's now far less of a contact footprint between the engine and the transom, so the load isn't spread out over as much of an area.

Merc specs show the 60 bigfoot with a dry weight of 264#. so with prop and fluids it's really getting close to the 300# threshold.
remember, even though (i believe) the Mac X or M transom can handle the weight and pushing force of a larger outboard motor, the original X was built for a light weight 180# Tohatsu 2-stroke on the rear.
that was later followed with a 205# Honda 4-stroke.
now...most are placing Suzuki 60/70 (350#), Etec 75/90 (320#), or Tohatsu 70/90 (320#).
and...in the offing will be the new tech 4-stroke Honda 75/90 that weighs 359#.

so in the future, nearly all Mac M motors will be over 300#.
bottom line, it doesn't cost much to place a couple of aluminum backing plates on the transom. i believe that it's money well spent.

Bob T.
"DāBob"
'02X w/ '04 90-TLDI (14" x 11 pitch)
Dinghy Motor: '06 2.5-Suzuki

I agree completely with anything over 300, and someday still might do it for mine.

Great article, Deja. Actually that would make a great 'mod' in the Mac Mod's section! Can't wait to hear your results on the water.

As for the solvent, I think you'll find that solvent alcohol (stove fuel) works as well or better than acetone for solving 3M 5200, and it's a lot safer to work with.

Good tip on the alcohol...wish I'd known or thought to try that since I have some sitting in the boat for the stove, will definitely keep it in mind for the future.

I'll add it to the mods at some point as soon as I can decide which pictures to keep. I did it this way because then I can use less words and more pictures and the pictures don't have to be hosted on this site. That way they won't be counted towards the monthly bandwidth quota for people viewing them all.

The problem is it'll be harder to find in the future.

All great stuff Jeff.

I felt like I was there with you the whole way.

I had to use the 5" bolts, but then again, with the heavier motor, I went with the same setup as Bobby T, ie plates in both places even though BWY doesn't use them for their 70 install so I have been told.

Nice pics, very easy to follow, as KM says will make a great guide for future mod's. It was your motor install post that guided and inspired me to mount my 75 and throttle myself

Thanks for being so thorough and generous with the information in your posts, many will benefit from your experiences.

I look forward to your results with those wedges. I mounted my motor so that the cav plate was even with the bottom of the boat, not the bottom of the transom as it would seem that these boats are so different from the norm, when they say to aim for the bottom of the transom... I think they are talking about a conventional power boat like a bass boat where that would be the bottom of the boat. It would seem that our has a low point around the keel area, not the transom, so I lined up with that instead. I am happy with the performance where it is so I am not planning on ever raising her up one hole, as a result, I guess I will never know if that would give me a higher top speed as it would with a bass boat. But then again, I think my boat is capable of going faster then intended by design anyway

I am finding I like to cruise around 18kts, ballast empty. I prefer to motor with the ballast empty as I just can't willingly lug around another 1250lbs for no reason. The boat is very stable at speed without it. The only time I find it useful is sailing, obviously, and in rough seas at much slower speeds.

Happy boating, and I hope everything works out for you.

Cheers

G

deja_vu,
Nice mod. Do you by any chance have some information concerning angles?

What degree angle is the X-boat's transom? The M? What angle are the wedges you used? Are there additional wedges with bigger or smaller angles available?