Outboard power options / questions

Last year I picked up a lil 2002 Mako 171. It came with a 2003 Merc 20” tall, 125HP 2+2 (idles on two carbs, runs out on 4 carbs). I never liked the way it ran. Just figured out it was way (WAY) over pitched. Came with a 21” pitch, finally just broke down and purchased a 17”. Runs lots better now. Also, this engine is mounted one hole to high on the transom. Even if I keep it, this has to come down a peg.

In the meantime, Found a 2003 25”, 135HP OptiMax. 1 month later, it is still in my van.

I’ve had these big (new) conversion brackets in my shop for about 10 years. Just for bolting on a 25” to a 20” transom. Ready to give this a try,,,,, I Think…

Other specs; The 125 is a 112.8 cubic inch, in line 4 lunger. Shares the same power head with the 115hp engine. 4 ¼” lower case. 2.07:1 lower ratio. On the power head oil reservoir. Weighs 348 lbs.

The 135 is a 153 cubic inch, 60° V-6. Direct fuel injection. Shares the same power head with the 150HP engine. 4 ¾” lower case. 2.00:1 lower ratio. Remote oil reservoir. Weighs 452 lbs. With brackets I can imagine 470 lbs back there.

The Mako is the inland model CC with a T top. Not a real V at the transom as the 172 coastal. I don’t think the extra weight will hurt it that much. When I stand on stern, the hull drops slightly. Pretty stable hull. Lenco trim tabs. The transom seems really solid. I had to drill thru it to install a swim-out platform, bone dry and solid.

I gave my engine hoist aweigh a couple of years ago. Trying to borrow it back. Probably going to SunBelt and rent one a few days.

So, brothers and sisters, my questions; Anybody delt with these engine brackets before? Going to bend over the transom? Looks like anodized aluminum, need primer and paint? Trim motor would not be in the water with this install.

Anybody dealt with this OptiMax stuff before? Worth a change or just lower what I have and keep it simple?

Anybody need an engine? Or two? Or a whole boat with spare engine?



Any other comments?



Thanks all for your thoughts

I keep changing my mind back and forth.
I'm a big fan of displacement, the more the better IMO. The V6 offers near a half liter more and direct fuel injection.
Not looking for performance, just the guts to get two heavy folk up and going.

I like the idea of the 135 but the adapter brackets that raise the 25" engine up over the 20" transom still bothers me a little.
Wish somebody here that has used this installation could offer their experiences with it.

If I can ever get a good feeling about raising it on these big angle brackets, It does have some benefits over the 20" install.
Mercury hardware, more of the bracket & trim motor is out/aweigh of the water.
Never liked the idea of these trim motors in the water.
Also, can build a better dike to keep following water out of the boat.
Just wish I can get a better feeling over these brackets.

Brother, thank you for your thoughts. Already considered this.

I did that on our 20 WellCraft work boat. I miss that boat, 3.0L/225 HP Mariner.
We did that rite including a 1/4", SS steel angle on top covering the whole transom width. Tow post resting against this.
3.0L/225Hp rite against the tow pole/post/pylon/bit.
Low pitch prop, we could pull like a monster and still make respectable speed chasing for business or towing.
Displacement does help. Did I mention I missed that boat??

Many boat shoppers did not understand these mods and turned away.
It was a local who wanted to fish AND drag his grand children around on big float toys that finally purchased her.

Retired now, Have to work with what we have on hand.
Still trying to keep our Bert up and wife is screaming,,,, again,,, at my expenses...

For now, I have to work with what I have on hand.

Oh, the above brackets (post #6) were purchased for this WellCraft.
I was not sure of them then, never used.
Somebody please tell me about using them on their boat.

Yep, I do miss that old WellCraft work boat. Early model V-20 based on the original Schoell Vega 20 ( I used to restore these, VP B18 and AquaMatic 100 drives)). WellCraft added more lifting strakes to get that great V out of the water with less horse power. This one had those lifting stakes but not lacking HP. No trim tabs required, at speed, just move your asp a few inches to adjust port/stb list.
My wife had nick names for our work boats; One was called Floater Boat, a 20' Chaparral that did look like a floating turd. Straight 302ci inboard. The only way to keep the bow up was to tow harder. Was a stern drive. To much weight forward. I kept plastic lift drums in the back full of water when speed was needed.
A 21 Sea Ox was called Dumb Ox. 225HP Yam 4 stroke. Probably the best offshore hull of our work boats but off of plane, wondered grossly.
This WellCraft was just called Ugly Boat. The last that sold a couple of years ago.

Jack plates, extension plates, riser plates,,,, they all change the angle of applied pressure on the low transom.Hense my concerns.
I have almost (80%) decided to go for it. I'll know better if/when we survive this next rain cloud.