El and Bill- Great topic......here we go again!!!
Casey- Great information and thinking! Ditto on the EFI endorsement!
Greg- I took the information on the various engines from their 2006 brochures, if that's what you're asking(?).
Choosing a motor can be a somewhat arduous task if you want to weigh all the facts, opinions, and other factors such as cost and service availability carefully before committing, but here goes.
I choose the Yamaha 90 last year for the following reasons which I think are still valid:
For 2005, Yamaha added Electronic Fuel Injection to all their models from 50-90 hp. EFI is more convenient, more reliable, more efficient, cleaner, and simply better than "Old School" carburetors. The engines start better, run smoother, use less gas, pollute less, and give you and your motor technician more information on what's going on with them. Carburetors are headed for the Museum of Outboard Artifacts and Old School Ideas.
I choose the 90 over the 75 because of the power reserve factor for heavier loads, although I mostly run in the 3800-4400 rpm bracket.
The Yamaha F90 weighs 369 lbs, well within the bracket defined by engines available in this class: Honda 75/90-373 lbs.; Suzuki DF90-416 lbs; Evinrude E-Tech 90-320 lbs. The Mercury 90 is a Yamaha except for the lower end=386 lbs.
The Yamaha 75/90 and 115 (actually all the Yamahas) are designed specifically for marine use, eg., an outboard engine designed as such and not an automobile engine adapted for use as an outboard and stood on end. The many hours of experience with an automobile engine design can eliminate many problems, of course, but standing it on end, putting it in a marine environment, and loading it up to work at heavy marine loads as compared to lighter auto loads, and at temperatures well below that in an automobile, can introduce new issues. I prefer a specific marine designed engine by a large scale world renown manufacturer with tons of experience in designing gas and diesel engines for cars, trucks, motorcycles, snowmobiles, jet skis, generators...you name it. I think such an engine can and will be a better product in the long run.
I preferred the simple direct 4 valve dual camshaft design of the Yamaha (and the Suzuki) over the single camshaft more complex three valve Civic engine design in the Honda. Even the Honda engines from 115 hp up use the same dual camshaft, 4 valve set up as the Yamaha. (Adding variable valve timing at the higher levels.)
The induction and exhaust systems in the Yamaha and Suzuki are more modern and efficient in design than the Honda.
The engine displacement of the Yamaha also is well placed among the choices: Honda 75/90 1590 cc, Yamaha/Mercury 75/90 1596 cc, Suzuki DF90 1950 (!) (Suzi DF 70 is a different block = 1298 cc), and E-Tech = 1295 cc (2-stroke).
The amperage output of the Yamaha is reasonable within the choices available: Honda = 16 amps, E-Tech = 25 amps, Yamaha/Mercury = 25 amps, and Suzuki = 40 amps(!). I think all of us need a good alternator output with the "stuff" we load onto our C-Dorys!
I liked the gear ratio of the Yamaha for a heavier boat like the C-Dory. Mercury 2.07 : 1, Honda 2.30 : 1, Yamaha 2.31 : 1, Suzuki 2.59 : 1, and E-Tech 2:1 for Freshwater model and 2.25:1 for the saltwater version.
The dealer network for Yamaha is very strong here in California. Several marine dealers in Redding alone sell Yamahas. The Honda network is also strong. The nearest Suzuki dealer is in Marysville, 90 miles away, although the Johnson dealers could easily work on a Suzuki, since the four stroke Johnsons are actually Suzukis.
The motor came with a three year warranty, which is pretty standard, as I remember it. The E-Tech curently comes with a 7 year warranty! Suzuki was offering a six year warranty at no extra cost at the time, but with the nearest dealer 90 miles away..... (However, I wound up buying the Yamaha from Gunther's in Santa Rosa because he was a C-Dory dealer and because of the deal he made to sell the old motors for no commission, which turned out to be a $1950 return with no effort to me.)
Overall, I just thought the Honda, by comparison, although a very high quality product, was in need of some serious updating.
The Suzuki DF-90 looks to be a "brute" of an engine with its 1950 cc of displacement, and the same block is also offered "tuned up" in the DF-115 version. The short dealer network and automobile design engine was the put-off, although I liked the chain driven valve train for engineering reasons (have not heard of anyone actually having problems with the rubber/fabric/ fiberglass or Kevlar (?) belts in all my readings.) The big block baby also comes with a slight penalty: 416 lbs. It's probably the strongest of the 90's (torque).
Since the Mercury and Johnson 4 strokes are Yamahas and Suzukis, respectively, they represent the same basic choices as before, except for the Mercs having their own make lower unit, which Flagold has assured me is a better foot than the original!
The real "sleeper" here is the Evinrude E-Tech with its light weight, high tech approach to modernizing the 2-stroke outboards. Most people will say that the jury is still out on this new baby, and it might be a little more of a "risk" until it has a longer track record. (The "ficht" snafu for Evinrude still lingers in some minds.) So far, however, most of the reports are positive from my readings on various sites. Trust Dusty to give us the real scoop as it develops. This may be the C-Dory engine of the future.
So when it came time to replace my aging Evinrude 90. I decided the Yamaha was the safest and best bet available, especially with the newly added EFI. I've had zero problems with it so far. If I had time, I could probably come up with a few more reasons why I think it's the best choice, but other items need my attention. I'll get to the criteria for the kicker in a later post! Joe.
How bout it Joe. Dig up some goodies for us. Right now my time is very limited for the web :? to go into this like I want. 