Outboards 2009 - HP, Weight, Make Comparison

"Engines keep getting better, more expensive and more complicated. Have you looked at the Tohatsu/Nissan LPDI 3cyl 2 strokes?"

The specs of the Nissan 50 hp, 3cyl. 697 cc @206 lbs (94 kg.) appear excellent. I have it on my list to investigate further. However, here in Colorado, boating supply sources are sparse. I haven't been to the Nissan dealer yet; it is a little further away. I also have been told by several mechanics & dealers that in this area I should stick with Mercury or Evinrude because sources for parts and service for the others are so limited.

A somewhat unique part of my learning and decision in this quest is that here in Colorado we have some beautiful lakes located at 9000+ foot altitude. The appropriate engine for a boat located on the coast may be too weak here. As I understand it, it takes about one hp per 50 pounds displ. to plane a hull, and an engine looses about 2% efficiency for every 1000 ft gain in altitude. As you say, engines are expensive, and I need to get a somewhat larger one for the approx. 1500 pounds at full load for the hull I am building or risk not getting "over the hump".

 

Wayne,
It sounds like hp per lb would be a big issue at that altitude. Any engine you buy should be fully able to compensate for the different fuel mixture (leaner) that you will require. I wonder if outboards come w the mixture excessively lean to minimize emissions or if the fuel mixture is optimum for performance? Early carberated cars had lots of problems and fuel injection seemed to solve the driveability issues but I've wondered since if the mixture is now perfect for performance or is it a compromise. I suspect the latter as I remember the old cars as being snappier but at 70 my memory may not be snappy either and I'm aware there are lots of other variables as well.

Easy Rider

 

Fuel injection really helps keep the engine running efficiently, and all the outboards I am considering have injection. You are correct that weight, of the entire loaded boat, will be critical. Since this boat is a semi-planing hull of my own design, I have to do some estimating of the constructed hull weight and of expected and desired performance. But, of course, that is what I signed up for in starting this project. I was originally thinking 30 hp but got what I think is good advice to use more power with a larger prop.

 

Wayne,
You will need a light boat. Can you easily tell me about the boat?

Easy Rider

 

Is there a reson no one talks about Honda?
I thought they are very good motors particularly quite and trouble free.

 

I looked at Honda when I bought my 60 Suzuki and at that time the Honda was carbureted. The Suzuki and all others had injection. The big issues I had w Honda was the prices and the small propellers. However a good friend of mine has a 20hp Honda on a 14' Lund and it performs well But lower gear ratio's and bigger props are always better at low to med-high speeds. I think small props are found on many outboards as a design compromise. They are much less sensitive to pitch and diameter. Small outboards are clamped onto boats w extreme variations in size, load and speed. It's hard to over speed or over load an outboard with a small high speed propeller. I feel I'm skillful enough and knowledgeable enough to run a big prop w low gears. Now that I have the very complicated Suzuki w fuel injection here in Alaska I may be better off W carburetors. The Honda's are by far the best looking of all the engines. And ther'e not black. When I got the E-tech for my 16' skiff I was looking for more simplicity and again the biggest prop.

Easy Rider

 

developable-surface-boat-designs.blogspot.com will show you more than you want to know. At this point I have sheathed the hull in 6 oz. cloth and epoxy resin and am sanding and filling to get it smooth. It will be an 18' x 5'8" runabout hull.

A 50 hp Honda is $1500 more than an equivalent 50 hp Mercury. A 40 hp Yamaha is $1000 more than a 40 hp Mercury, and this engine was jointly developed by the two companies (same weight, disp., and hp). That is why I doubt if I will end up with a Honda or Yamaha. The 40 hp Merc, 50 hp Nissan and 60hp Suzuki are what I am presently considering. Haven't got a price on the Nissan or Suzuki yet, but there's plenty of work to do before I need to make a final decision.

 

Nissans are Tohatsu painted grey with a slightly higher price.

 

The new 2010 Suzuki 60 weighs less than their 40 & 50 !!!! It's great...The old 60 was heavy .

 

Today I finally talked with the local Nissan/Tohatsu dealer (70 miles away). He said that their TDLI two-stroke engines have had problems at the mountain lake altitudes (about 9000 feet) but that the problem has just now been fixed. New stock will have a revised control to handle the altitude, and a repair kit for older engines will be available soon. 50 hp in a 206 pound engine is very attractive; I will be investigating this further.

 

Mercury certainly seems to be the dominant brand in many of my cruising areas. I think this is more for historical reasons- it's always been that way, so the service/dealer network is there- than for any current technical reason. Johnson/Evinrude from the OMC days are also very popular; the things just don't die and parts are still readily available. Yamaha and Honda are occasionally seen in these parts; Suzuki, Tohatsu, Nissan are quite rare.

There's a new brand called APS that I've seen a few examples of- they're sold through Canadian Tire, $2000 for 9.9hp and the owner reports, so far, don't seem particularly good.... I haven't seen one dismantled yet, but they look an awful lot like a Chinese clone of an older Merc four-stroke.

I'm with Easy Rider on the props issue- let's see some steeper gear reductions and larger diameter props on these things. The stock small gearcases are fine for a little aluminum fishing skiff, but it'd be really great if more manufacturers would start offering optional, larger lower units with 2.5 or 3 to 1 reduction and the ability to swing, say, an 18" prop on 50-60 hp. Only a couple of them are doing this right now- there's a reason why so many pontoons and working boats run Merc or Yamaha. Evinrude's latest are getting better, with 2.67:1 ratios as standard on many models....

Oh, and what the !@#$ happened to outboard prices lately? A 60 hp Honda is $7500, a 60 hp Yamaha is a hair over $9000.... only a few hundred bucks short of a new Kia Rio sedan and more than the average student pays in rent for a year.

 

Marshmat
The problem with putting a large gearbox on a smal engine ( and yes it would be great) is that the thrust it can create and more of a problem is in reverse is that the load is more than the transom bracket/swivel tube can handle.
This has happened to manufacturers before when they have made high thrust engines and you break things that you normaly couldnt.

A manual tilt engine will need a massive reverse lock so if you then impact somethng in forward..its going to be ugly depending how thats configured.
You also have the problem to ensure the engine can produce enough power at idle so when it goes into gear it wont stop

Depending on the model some smaller engines do use the the larger horsepower brackets so they could do it but its not as straight forward as one would think.
Not to mention just about all outboards and the accessories are designed for bass boats