Do I Need To Repower??

ChrisP and Pam · Post by **ChrisP and Pam** » Fri Dec 28, 2007 6:51 am

Beene,
That sounds like you're hitting the numbers with that motor!!! Hoooray! And I don't think you're in overkill with a 75hp motor. Great Great!
Thank You, Beene. I'll pm you later if you don't mind.

To Catigale and Chip,
and anyone else who argues that it's not right to use 22mph, I have to say forget the technical manuals for a second and think of it like this, if you bring a friend for a weekend trip, what do you do when they want to see the Mac go fast? You can't nose-up-plow and start reading the warranty specs. That's a joke. I'm looking for those who found the Mac-motor combo that works in real life. That's all.

Gazmn,
Fifteen knots is 17mph.... that sounds wrong. I can almost get that with my 60. Is that a gps number? You could probably expect 20mph loaded unless you just have an enormous amount of stuff or have a motor problem.
Maybe you can leave some of that stuff in the garage. Anything I didn't use on the last trip doesn't come on the next trip. I'll be looking forward to your numbers after your boat diet.

Who Else Can Brag 22mph in an 'oversized' 75hp or above? What kind of powered performance are you getting? Are you able to safely cruise 2 with a weight-conscious 3-4 days of supplies and safety equipment and reliably get 22mph or better in ideal conditions?

Catigale · Post by **Catigale** » Fri Dec 28, 2007 7:05 am

if you bring a friend for a weekend trip, what do you do when they want to see the Mac go fast?

I put up another sail

(No offense taken Chris....

)

Gazmn · Post by **Gazmn** » Fri Dec 28, 2007 8:36 am

Hi Again,

I don't want to hijack your thread with my motor/ speed dilema. I was just giving you my results as a 90 hp owner. As an example, I'm sure that there are many more things that Capts like Beene, and other high HP owners, are doing right - that I as a new boat owner am still getting wrong.

I'm sure my weight distribution is off. I got laughed at by the last mech in terms of what I had in my boat.

One day I hope to get it right and enjoy the higher numbers others are touting.

I think I'm only off by about 4+kts. Oh and my reading is knotts as read by my Garmin 498 GPS.

I am hoping to get on the scales and weigh my beast to also help in determinig my "issues".

Until next season, she's up on the hard & this board is my fix.

I'm okay with the #'s I'm getting to the extent that the answer is not putting on a bigger engine.

You too will have to ask yourself what 4 or 5 kt$ i$ worth

Happy Boating

Highlander · Post by **Highlander** » Fri Dec 28, 2007 8:39 am

Hi Cat.

Oh yeah I,m still waiting to see Pic's of that cutter rig X set up of your's in action yet

or is that just to many lines for you to handle

extra sail does not include flying "drying" your undershorts off the topping lift

Went sailing on Mon. Dec 24/ 07

J.

Bobby T.-26X #4767 · Post by **Bobby T.-26X #4767** » Fri Dec 28, 2007 9:13 am

ChrisP and Pam wrote: So, to anyone who has a 90hp or above, what kind of powered performance are you getting? Are you able to safely cruise 2 with 3-4 days of supplies and safety equipment and reliably get 22mph or better in ideal conditions?

'02 Mac-X w/ '04 Tohatsu 90 TLDI:

27 mph / 5600 rpm at WOT lightly loaded.
22 mph at WOT fully loaded (gear & 2 passengers).
17-20 mph typical cruising speed (3/4 throttle) when crossing 60 miles in open ocean from Oceanside to Catalina.

i use an 11 pitch prop which gets me to maximum rpm but i sacrifice top end speed.
others with 90 tohatsu have used 13 pitch to attain 30+mph (lightly loaded) but experience less desireable results under a load. that is, not able to reach max rpm specification which can cause motor damage under prolong use.

those who follow this board know my story.
i was an unhappy camper with the 50 suzuki and sold it two years new in exchange for the 90 tohatsu tldi. it's been a great motor for the X. trouble free, proven reliability. weighs 320#.

today, i would probably opt for the new Honda 90 VTEC. that looks like the ticket as it weighs about 365# and is the lightest 4-stroke available in the 75-90hp class.

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

Catigale · Post by **Catigale** » Fri Dec 28, 2007 2:53 pm

John - look far ahead - you can see me...that little white spec on the horizon..

Highlander · Post by **Highlander** » Sat Dec 29, 2007 7:04 am

Cat

You Wish, !! Your getting delusional in your old age

J

Highlander · Post by **Highlander** » Sat Dec 29, 2007 7:18 am

I just got a nice quote on an 08 suzi 70hp & 90hp Hmmmmmmm !! what to do , gonna check out the weight diff. between them & the new Honda 90hp, thinking the new honda 90 is newer technoligy should maybe leave alone until it has proven itself !!!

J

beene · Post by **beene** » Sat Dec 29, 2007 8:02 am

Get Suzi over the Honda for sure J.....

Honda 90 4s efi = 1496cc
Suzi 90 4s efi = 1950cc

I said it before, I'll say it again.... ITS TORQUE THAT MOVES THESE BOATS

G

Highlander · Post by **Highlander** » Sat Dec 29, 2007 9:04 am

Hi Beene

The suzi 115 & 90 are the same 4/stroke block weight is 415#

115 has an wot range of 5200-5800rpm's "600rpm range "

90 has an wot range of 4500-5500rpm's " 1000rpm range"

So it would appear that the 90 has more lower end torque !!! and would be the better choice plus about 1 1/2 boat bucks cheaper

than the 115 and would allow me to use my suzi SS flush mount remote control which cost 760 I got on sale for 240

Not sure I like honda's new V-tec valve control system which is only avail on the 90hp !! most likely where its getting the extra hp from the 75 !
the honda 90 does not weight in at 320# as stated above . But actually weights in at 360# so for a diff of 55# , big block, more torque, should be more fuel efficient !

some more pondering to do !!!!!!!

waternwaves · Post by **waternwaves** » Sat Dec 29, 2007 10:20 am

I cant believe you wont go Canadien with Bombardier.....

E-tec 90......

Bobby T.-26X #4767 · Post by **Bobby T.-26X #4767** » Sat Dec 29, 2007 12:06 pm

Highlander wrote: the honda 90 does not weight in at 320# as stated above . But actually weights in at 360# so for a diff of 55# , big block, more torque, should be more fuel efficient !

look again...you read it wrong.
it's the tohatsu 90 that weighs in about 320#.

BTW...i cannot believe that you're actually thinking about putting a 400# motor on the rear end of a Mac 19.

IMHO...i would not consider anything more than a yamaha 60 high thrust or an etec 60.

but hey!!! whatever floats your boat...

Bobby T.-26X #4767 · Post by **Bobby T.-26X #4767** » Sat Dec 29, 2007 12:10 pm

beene wrote:Get Suzi over the Honda for sure J.....

Honda 90 4s efi = 1496cc
Suzi 90 4s efi = 1950cc

I said it before, I'll say it again.... ITS TORQUE THAT MOVES THESE BOATS

G

IMHO...if you're considering a suzi 90 for your Mac, you might as well step up to a 115 or 140hp since it's the same powerhead.
that is, the 90 is a de-tuned 140.

Catigale · Post by **Catigale** » Sat Dec 29, 2007 12:42 pm

Isnt that 140 just a detuned 280? Might as well step up

ronacarme · Post by **ronacarme** » Sat Dec 29, 2007 12:57 pm

Your WOT 5500 rpm seems close enuf to motor's max (6000 rpm?). Before re-propping or re-motoring, I'd experiment with fore-aft weight distribution.
You mention "not planing", "plowing", "nose up plow" at WOT. Also, you have 24 gallons of gasoline (about 150 #) presumably near the stern, a second person ( 150-200#?) in the cockpit, a second battery (say 50#) presumably in aft part of cabin and a fairly heavy motor (300#) on the transom. I believe the M has a less wide/flat aft bottom portion than an X and may be harder to plane than an X.
Given the above, I'd try shifting as much weight from rear to front as possible and seeing if that reduces plowing at WOT. If so, it may up top speed a bit.
At least I'd try WOT with only a few gallons of gas in the tank, only the helmsman in cockpit and and a couple of hefty people jammed in the v-berth (safer than on the bow). Cheap and easy experiment.

MacGregorSailors.com

MacGregorSailors.com

Do I Need To Repower??

ChrisP