Max Horsepower for '01 26 x

[Jimmyt]

Hi MallardAdjusted!

Yer pranking me …Right?

Nope, those are the "rules" I was referencing. Maybe you missed the bottom of his post, "Lt, USCGR retired".

Testing complex structures/assemblies to failure is a common verification methodology. Fortunately, no one on this board has found the horsepower limit (yet).

But, no matter. Unless someone is going to run an analysis on the structure of the X or M, and get a solid answer with reasonable margins for safety, this thread has run its course. Posts have degenerated to the point where we're standing in a line seeing who can urinate upwind farther. Like that process, none are benefitting from the experience.

Everyone needs to agree to disagree and move on so the moderators don't have to shut it down.

[Sea]

New here, and considering buying a Mac that needs a new engine.

Just read though the whole thread, and was amused to see the usual devolution when someone asks a simple question such as this.

So back on topic, ish... Anyone know if a new (2022) 115HP Yamaha 4 Stroke will fit on the X/M without any clearance issues?

Also, does anyone have photos they'd be willing to share of the reinforcement they have done when installing a big boi motor? I've been scourering the internet and found lots of old threads with mentions of reinforcements completed, but the pictures are either non existent or are so old the host has taken them offline.

[Jimmyt]

Welcome to the forum. Hopefully someone will post pics of their transom mods.

This is a friendly group, and it is unusual for a discussion to get snarky.

A 115hp should be right sporty.

[Sheppie62]

A Yamaha 115 will most likely hit the back seat, but may go up high enough to trailer. Some people have cut the back part of the seat to get a bit more room, others set motor back (more leverage on transom). I believe the worst issue of the heavier motors is motor bouncing/ slamming while being trailered. A larger motor causes issues with the steering when sailing if left connected. Weight I hear makes the steering try to steer more once turned. Also with a bigger motor you should have more robust steering in my opinion. It is not a simple bolt on. Suzuki 90 is much simpler, many have done that already with success.

[NiceAft]

Sea,

First of all, if you don’t mind me asking, why is it that you are most specifically interested in 115 hp?

Second, how far upstate NY are you? I will be in Saratoga Springs this weekend, and am always interested in meeting a fellow Mac owner.

[Sea]

Sea,

First of all, if you don’t mind me asking, why is it that you are most specifically interested in 115 hp?

Second, how far upstate NY are you? I will be in Saratoga Springs this weekend, and am always interested in meeting a fellow Mac owner.

The Yamaha 115hp is appealing because it's the same physical size as their 75 and 90hp motors, may as well get the most powerful version for the weight. The 70hp Yamaha, though light, seems a bit anemic for the Mac26 from what I've read, with only 1L displacement. I'd like to be able to get the boat moving at a good pace when loaded with two adults, two kids, and too much gear, and don't want the motor constantly at 100% to do so.

Realistically, if I buy the boat I'm eyeing that needs a motor, I'd probably end up with the Suzuki 90hp, as it seems easier and likely is far more affordable than the Yamaha.


I live in Columbia County New York, so Saratoga Springs isn't too far, what brings you up that way? Any chance you're passing through the Newburgh/Middletown area and want to look at a tired old Mac 26X with me? I've sailed my whole life so I know a thing or two about boats, but very little about the Mac!

[Sheppie62]

Sea wrote: The Yamaha 115hp is appealing because it's the same physical size as their 75 and 90hp motors, may as well get the most powerful version for the weight.
Same is true of the Mercury 75/90/115, they are 18lbs lighter than the Yamahas. Mercury is 2100cc vs 1800cc’s. Mercury has 2 valves per cylinder, and is available with the larger lower unit for bigger prop. Add 4 lbs still 14lbs lighter. Yamaha may run better at high rpm’s, but if your goal is cruising mercury might work better. FWIW Mercury’s are cheaper also, the Suzuki may be better for resale, simpler install.

[dlandersson]

Why limit yourself to only one? Why not two?

[adudinsk]

Blue water yachts had a approval/agreement with MacGregor to mod for a 60HP.
I have a 75, and it has a large metal (al) plate on the back.. will look to see if I have any old Photos about.. if not I will have to wait until I unwrap the boat.

Also agreed.. I have a F75.. its the SAME as a F90 merc.. very slight diff to the F115.
The 90 has a different program in the computer .. and a slightly different carb (jet sizes) ... and restrictor plate on the carb..

Not a huge issue to convert an F75 to a 90 if you can get someone to program our computer module.

[Billy]

If it helps, this is the way I mounted my Suzuki DF 140 back in
2002. Mostly flat aluminum stock and transom wedges. You really need the wedges to maintain the correct attitude on the X.

The 2 outside vertical pieces are 13.5 x 4 x .5 inches with the top machined out .25 x1.75 inches to allow for the overlap of the upper hull. Add the transom wedges here.

The upper horizontal piece inside the motor well is approximately 14 x 2.5 x 3/8 inches. This piece will need to be shaped to the contour of the well and the end edges all rounded to prevent pressure points. (I used a hammer and grinder to shape.) The idea of all of these parts is to evenly spread the load.

The lower horizontal bar is 14 x 2.5 x 3/8 inches.

This was probably all overkill but it made me feel good with this much hp. With over 600 hours on the clock this set-up has not yet failed. I've reversed at over 4000 rpms. The boat was swept over a reef and kick the engine up out of the water while under power. It's covered the Carolinas, Florida including the keys, and several trips to the Bahamas. I can find no signs of fatigue, cracks, or failure.
I do not endorse doing this, but I would do it all over again. If you choose this route be responsible and use common sense. To avoid increased shock loads to the rigging while planing, i run my extra halyards to the forward cleats or bow rail.

Measurements are all approximate. It was difficult to measure.
Any other questions?

[Sheppie62]

Thanks Billy, that is basically what I did. I used 3/8” 6061 aluminum in the motor well, shaped to fit the entire flat space with corners rounded a lot. I used about 1/8” of semi flexible marine adhesive (under the entire piece) to get an even contact surface (used the bolts and C clamps to squeeze excess adhesive out) and to help eliminate chafing and vibrations damage on the boat. Same for bottom bolts/plate inside, made a cardboard cutout to fit as large a piece as possible under there. Outside I put plexiglass with the flexable marine adhesive I spread with a notched trowel, I immediately bolted a setback plate to make adhesive to conform to back of boat (mount was 2 piece so it bolted 2 cross pieces so motor holes would line up perfectly with no additional stress). I modified/ extended a very heavy duty setback plate 1/2” short of the bottom of the boat. I did this to get pressure to push on bottom of the boat, and decrease leverage, and to help eliminate any flexing near the ballast tank inside. I am not recommending you do this, just telling what I did. And I will keep a close eye on it for any signs of flexing/ cracking.

[vkmaynard]

We followed Billy with the overkill plates. The upper inside can be seen here. https://youtu.be/HqKgqweVZVQ

No issues since 2010 install.

Victor

[JaxMacX]

Vkmanyard, I think that is exactly the motor we will plan to install next winter . Was there anything that you had to do to get the motor on? Thanks for the videos. That convinced us for sure!

[vkmaynard]

Here is the link for my engine install. viewtopic.php?t=15666#p183156

I have the pictures. I sold the kidtech domain that was used in the link. Will post.

Victor

[OverEasy]

Just a thought: Just how much horse power is actually required to pull an adult water skier….?



Answer: One


Just a thought…

fudt