Powering up a new MacM

[aya16]

side note Delevi: I would still flush the motor after use in saltwater.
same as using it in harsh fresh water conditions. Marine life will get up into your motor and any trapped salt water will keep them alive for months growing and sticking to the inside of your motor. after a while they will build up and cause water flow problems.

Not only that salt will build up after the motor dries out and do the same thing. Water pumps will build up with salt and cause friction and wear out sooner. There are alot of reasons to flush and none not too.
do what you want but I would flush everytime.


rjs11116: do you have a transducer for a depth finder bolted to the transom close to the prop? This will cause what you said. The transducer should be as far away from the engine (to the side) as possible.
the other thing that could cause the problem is a bad prop.


No one ever complains about to much power..............

[Matt19020]

Well I sure have more to think about now then I did before I started. I am definitly curious about the etec. I am going to investigate it more before I narrow my scope.

[nemo]

I like the Suz 70 that we have on our M - it was the max for the warranty to hold according to what I heard when I bought it (2 yrs ago). I wish it had twice the power.

[Divecoz]

We have the 05 M and with a 50 HP BF Mercury. We have had it at WOT twice maybe 3 times. We BTW slip our Mac on Lake Michigan. Now as has been discussed here earlier. We and several others who don't / haven't found we need or want to pull water toys , so we have been having a on going discussion about changing down to smaller motors on the Mac's and using our 50's on another craft.
Yes the Merc is very quite till you hit about 2500 rpm and that is all the speed we have ever really needed or wanted. AGAIN ! that is what suits our style /needs etc. As they say your needs may be different. Having owned numerous Ski Boats IMHO the Mac doesn't (imho) handle well at speeds much over 10 mph. But AGAIN each to his own, needs wants and desires.

[Bransher]

I just purchased a new M, and am waiting for delivery. I have been following the comments on this site for several weeks and have observed a wide range of opinions. My thought is that if the designer of the boat hull recommends a maximum of 50hp, maybe we should be listening to him. He says his reasoning is the ability to hand start it, and the best power to weight ratio. What he doesn't speak about, but what I think he might also be considering, is the stress on the hull when powering through rough water. I selected the 50hp Suzuki because of the fuel injection, timing chain instead of belt, and extended 6 year warrenty. Sounds good to me.

By the way, I'm having trouble deciphering all of your acronyms such as WOT, BTW, and IMHO. Do you folks publish a dictionary for newcomers like me?

[Craig LaForce]

Wide open throttle, by the way, in my humble opinion.

[Bobby T.-26X #4767]

By the way, I'm having trouble deciphering all of your acronyms such as WOT, BTW, and IMHO. Do you folks publish a dictionary for newcomers like me?

click here! On-Line Acronyms

[vkmaynard]

Get the Suzuki 70-4 . I have the Honda 50 with a 4 blade prop. It tops out at 17 MPH and will pull our kids wakeboarding. However, we run it at WOT 5800 RPM (6000 Redline). 20 more horses would be great.

Friday I hitched a ride on Billy's 140 Suzuki X. That motor ran 10X smoother and quieter than the Honda 50. At idle you can barely hear or feel the motor. I would definitely buy a Suzuki next time.

Victor

[Bransher]

Thank you Craig and Bobby for the help with the acronyms. Seems like it wouldn't be that much trouble to just spell it out.

[nemo]

The factory does allow full warranty when a Suz 70 is installed by one of their authorized dealers. Blue Water Yachts in Seattle is one that can do it - I would guess most of the others can too.

You make a good point that the Mac likely would take a thrashing with too large a motor in rough water, even if one could live with the extra weight.

[Bobby T.-26X #4767]

i really like my 310# Tohatsu 90-TLDI. narrow powerhead, great low end torque, and extremely fuel efficient.
i only wish that a light weight 300# 90hp 4-stroke Suzuki was available.
a Suzi 70hp weighs 335#, while a 90, 115, or 140hp weighs nearly 425# (w/ prop and fluids).

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

[James V]

Bransher - a few things tha this board will never resolve. One is how big or small a motor. As we have said, to each his own. We all will be doing different things on the boat. I like my 50 hp for 2 things. 12 amps charging at 2000 rpms and that it will move me and my boat at 17 mph. In Mar I went from Marathon Fl to Everglades City in 6 hrs on 23 gal of gas.

Have fun.

[Divecoz]

Bransher - a few things tha this board will never resolve. One is how big of small a motor. As we have said, to each his own. We all will be doing different things on the boat. I like my 50 hp for 2 things. 12 amps charging at 2000 rpms and that it will move me and my boat at 17 mph. In Mar I went from Marathon Fl to Everglades City in 6 hrs on 23 gal of gas.

Have fun.

JamesV would I then be correct to assume you actually traveled in the neighborhood of 100 miles ? Did then get around 4.4 mpg?
Please if you would tell us a little more about the trip . Average speed and approximate trip length in miles. Did you burn a similar amount of gas on the return trip?

[James V]

That part of the trip was dead calm, Flat, near glass seas and about 4 hr's into the trip a tail wind came up and my speed increased to 18.5. The trip was about 90 miles and 80 miles was WOT about 17.5 mph and I did get about 4 mpg. This motor was new, less than 100 hrs. 14X10 SS prop. Empty ballest and about 70 degrees, not much humidity. Lightly loaded.

Return trip, no, not that time. I did the Fl loop on that trip, so there was no return trip.

In May I went to Bimini. Part of the trip was from Marco Island to Long Key with a bit of wind from the beam and on the nose. I used 27 gal on that trip, I did it in 7 hrs. Head winds and ruff seas, very wet ride. The return was better. I had a full ballest tank. This makes a little differance with speed and gas milage. However the ride is much smother and safer.

I have 2-12 gal, 1 - 5 and 1-1gal

[Night Sailor]

I don't think hp is nearly important as torque for our fully loaded Macs. What's really important is how can you move the loaded boat at hull speed in heavy seas and high winds, where control is a matter of serious concern.

A motor that will handle a big eared, large diameter, four blade prop at mid range or lower rpms would be my choice based on my experiences. High revving, high speed, high hp motors are fun in calm conditions, but when things get scary, most of them don't let you control the boat's speed and direction as well at hull speed or below.

It was a major improvement in handling at slow speed when I moved from a 3 blade 11" prop on my '97 Merc 50hp 2 stroke to a 12.4 " four blade. This has been a very good factor in handling breakers, larger seas and rips, tidal currents and wakes from barges and large powerboats. The 50 has always been enough hp even into 40 knot winds with six foot waves, and gets 16 mph when fully loaded with cruising stores and crew. Modern engines might get better whether 2 or four stroke, but for the same hp I'd again go 2 stroke simply because even with my ancient engine, it's only required 1 part replacement in 9 years, a starting relay. Simple engine, fewer parts, lighter weight, smaller package. Stern boarding is still possible and it doesn't interfere with the stock ladder location.