Outboard Motor Decision Help Needed - Have 1-1/2 Day Window

[ChrisP and Pam]

Outboard Motor Decision Help Needed - Have 1-1/2 Day Window

I found a new 2005/2006 90hp 4s Yamaha motor for sale by a dealer (far from home) that has to move to another building and they're selling it for pretty darn good pricing (the same goes for a 150 Yam 4s). I think they need the cash and I have a day and a half long window to decide.

So does anybody have a Yam 4s 90 on your boat or (gulp) an opinion on such a motor on the Mac?

Is the 2005/6 technology somewhat dated or roughly the same?

[Bobby T.-26X #4767]

it should be fine.
it looks like there's been no changes on that model in several years.
weighs about the same as a Suzuki 70hp 4 stroke @ 369# (dry weight).
has more cubic inches and cc's than a 90hp 2 stroke @ 97ci & 1596cc respectively.
i don't recall many regulars (if any) on this board that have a 90 Yamaha on the rear of their Mac X/M.
but...if the price is right and the appropriate transom reinforcements are utilized, you should not have a problem and be very happy.



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

[Catigale]

CHRIS - make sure it isnt a gray market motor that you cant get warranty service on!!! There have been documented cases where people bought motors from US dealers and found they were Canadian motors with no warranty...ugh...

[beene]

I like it

Looks mean



G

[Night Sailor]

My perspecitve is from a limited retirement income, but not only do I see more hp, but more cost up front than necessary, and continued higher cost for fuel which already climbing steadily to stratospheric range.
Great deal or no, I think you will be happier saying no thanks to higher initial cost than a 50 or 60, continued fuel costs, and the weight on the stern that you can never get rid of while sailing.

[Catigale]

Counterpoint on fuel economy - your consumption will be pretty much (+-10 percent) a function of your speed, not your engine size.

Cruising at 6 kts with either a 50 or 90 HP motor will consume the same amount of fuel pretty much. Of course the 90 HP opens up the >20 mph speed range where you will burn (a lot) more fuel

[Night Sailor]

Certainly mileage may vary among boats and brands. I don't know of a direct cocmparison on a Mac that has been precisely measured. My old dock neighbor with a 17 ft. power boat said after going up from 40 to 75 hp his mileage decreased by 1.5 gph at the same rpm. Doesn't sound like much and isn't if you seldom use your boat, but adds up fast if you use the boat often of for longer trips. Of course, the difference is much greater at higher rpm.

It just makes sense on any boat that there will be a difference as not only the extra weight must be carried, but the stern will drag in the water more to change the waterline hull shape. Another 100 lbs on the stern will definitely make a difference under sail in light winds.

[Robert]

Same RPM from on two very different size outboards will provide very different boat speed. The larger motor moves the boat faster at the same RPM. To compare fuel consumption compare at the same boat speeds.
..

[Craig LaForce]

Luke. Don't give in to the Power. That leads to the Dark Side.

Mind what you have learned, save you it can.

[beene]

Another 100 lbs on the stern will definitely make a difference under sail in light winds.

With these boats, non performance sailboats, I seriously doubt that. I had a 7.5 Honda on my M first, then mounted the 75 Merc, nil difference on sailing performance that I have seen.

As for fuel economy, I use the bruit force of the 1596cc to get out of the hole and on plane fast, then back off and hold the plane at 3700 rpm 20pmh.

I have not conducted scientific testing to determine the absolute best engine for these boats, for fuel economy/top speed or anything. But I feel that getting the Mac out of the hole and on top is conducive to better fuel economy IMHO.

G