Small Outboard (on a sailboat over 30')

[fourlyons]

Yep, though mine are 18 years old now, but they are still made.

One down side to consider is the lack of real charging ability. My motors have 10 amp charging coils, it's something but not much. On the other hand two of these motors is a lot cheaper than the equivalent inboard.

[Shawn67]

The Suzuki has a 12 amp alternator and fuel injected.

Shawn

[a64pilot]

Originally Posted by fourlyons

Yep, though mine are 18 years old now, but they are still made.

One down side to consider is the lack of real charging ability. My motors have 10 amp charging coils, it's something but not much. On the other hand two of these motors is a lot cheaper than the equivalent inboard.

I think I could get over that with a Honda, one will run a 100 amp charger, and that is about all I can really get out of my 165 amp alternator continuously due to heat.

[a64pilot]

Originally Posted by Shawn67

The Suzuki has a 12 amp alternator and fuel injected.

Shawn

I don’t think it’s a high thrust though is it?
Also I believe the Suzuki 9.9 is identical to the 20 HP. If so I think I wouldn’t mind running the 9.9 hard as wide open is 50% power.

[thomm225]

Originally Posted by fourlyons

Yep, though mine are 18 years old now, but they are still made.

One down side to consider is the lack of real charging ability. My motors have 10 amp charging coils, it's something but not much. On the other hand two of these motors is a lot cheaper than the equivalent inboard.

Yes I can see how charging might be a problem but my 5 hp motor is pull start so I haven't had to deal with that on this boat. I have solar for house power.

But when I was in my teens, I would take the charged battery out of my car and put it on the boat and let my car's alternator charge the boat battery. I did this often

I let the car run on the alternator while I switched them

[Shawn67]

The Suzuki 9.9BTX has a 10” 4 blade high thrust prop on it. The 9.9b is the same block as the 15 and 20hp. Just a restrictor and probably different software in the computer to change the rev limiter. They make more hp by spinning faster. Torque down low would be the same.

Shawn

[fourlyons]

True high thrust outboards have lower gearing in the lower unit, usually close to 3:1, allowing them to turn a larger prop with flatter pitch. The Yamaha has a 2.9:1 lower unit and turns an 11 3/4" prop. The Suzuki has the standard 2:1 ratio lower unit found in most outboards.

[Shawn67]

Originally Posted by fourlyons

True high thrust outboards have lower gearing in the lower unit, usually close to 3:1, allowing them to turn a larger prop with flatter pitch. The Yamaha has a 2.9:1 lower unit and turns an 11 3/4" prop. The Suzuki has the standard 2:1 ratio lower unit found in most outboards.

The Yamaha has a bigger prop but it is pitched higher (7") and only 3 blades. The Suzuki is 4 blades and a 5" pitch.

The Suzuki also has more than a 50% increase in displacement (327cc vs 212cc) than the Yamaha so it doesn't need to be geared lower to drive a high thrust prop as it will develop more low end torque due to the greater displacement. That is also why it has the same HP at a lower RPM. Same engine is also used for their 15 or 20hp models. Only difference is the engine control unit and a restrictor on the 9.9B.

Shawn

[fourlyons]

Yes Shaun, that's all true. Now imagine the thrust that engine would have if they put a proper lower unit on it allowing them to spin a proper prop

I kind of think we're speaking past each other. Suzuki took a 20 hp outboard, detuned it, changed the prop, and called it high thrust. Well, I could just take a regular old 20hp, and I bet it would produce the same bollard pull (thrust) as a 9.9 properly set up as a high thrust motor; that is, high thrust compared to a standard 9.9. Comparing the Suzuki to the Yamaha is apples to oranges.

I wish Suzuki had made a 20 hp high thrust rather than taking a 20hp and making it a 9.9. My engines are getting old and I would be very interested in them then.

Best, Mike

[HellBentSailing]

Viking 33 in my marina is using what I believe to by a Yamaha 9.9 high thrust in some kind of custom integrated outboard well setup. Can't testify whether or not it works because the boat hasn't moved in a long time but it must have at one point or another if they got it here.

[Shawn67]

Originally Posted by fourlyons

Yes Shaun, that's all true. Now imagine the thrust that engine would have if they put a proper lower unit on it allowing them to spin a proper prop

I kind of think we're speaking past each other. Suzuki took a 20 hp outboard, detuned it, changed the prop, and called it high thrust. Well, I could just take a regular old 20hp, and I bet it would produce the same bollard pull (thrust) as a 9.9 properly set up as a high thrust motor; that is, high thrust compared to a standard 9.9. Comparing the Suzuki to the Yamaha is apples to oranges.

I wish Suzuki had made a 20 hp high thrust rather than taking a 20hp and making it a 9.9. My engines are getting old and I would be very interested in them then.

Suzuki took their existing 9.9hp engine, extended it to 25"s, put a different gear case on it (to clear the big prop) and then put the large prop on it and called it a high thrust unit. That the engine already had the displacement to push that prop is why they didn't need to gear it down.

If you want a high thrust 20hp you could buy the 9.9BTX and then order silencer seal 13832-89L00 $7.64, flame arrester13710-89L00 $10.10. Those would replace the restrictor that is on the 9.9 and 15hp engines. Then get the computer out of the 20hp 33920-89LA0 for $391.81 and your engine is now 20hp. The rest of the engine is identical (fuel injectors, pumps, block...etc...etc) While you are at it get their engine interface to give you NMEA output for full instrumentation on your chartplotter.

I'd be willing to bet that below 2500 or 3,000 rpm or so there would be almost no difference. Airflow needs of an engine are linear with RPM. Double RPM, the engine needs twice as much air. The restrictor wouldn't do much of anything down low and then the restrictor would start having more and more of an effect as RPM climbed as it would be choking off the engine and reducing its torque at higher RPM. That would decrease HP since HP = (torque x rpm) / 5252. You can see that in action by calculating the torque produced at peak output for the three versions. On the 9.9 it is about 10 ft/pounds at 5200rpm, 14 ft/lbs on the 15 at its peak of 5500 and 18 ft/lbs on the 20hp at its peak of 5800 rpm. The lower engines have their torque dropping due to their volumetric efficiency being reduced by the restrictor. The different computers are likely tuned for that and also have different rev limiters in them.

Shawn

[Fore and Aft]

Thom225 I hear what you are saying about old engines. Have you had a good look on Craigslist for a new old motor? I found a new old 20hp Yanmar 2GMF for $4000 AU still in its crate. It came from a failed boat building project and had been sitting around for years.
I wonder if you could put a custom fibreglass box under that tiller for an outboard? Nothing wrong with outboards, but I just hate the way they detract from the sweet lines of a yacht. Plus less chance of the prop coming out of the water in a chop.
That Viking looks a nice yacht.
Cheers

[a64pilot]

All the newer Suzuki 9.9, 15, and 20 HP motors are the same motor, not just the long shaft.
I was unaware of a restrictor, I thought it was just tuning.
However it of course means it’s a big and heavy 9.9, but it ought to last a good long time, cause it’s never run hard as it’s power is restricted to 50%.

Really sweet thing about outboards is they take a lot of the sting out of repowering.

I don’t know about the 9.9. But the 20HP between 3 to 5 thousand RPM goes into lean burn, and it’s fuel burn is significantly reduced

[Shawn67]

You can see the restrictor on the parts sheet for the engines.
https://www.brownspoint.com/store/pc...l.asp?ID=20857

Yes, they are all lean burn.

Definitely heavy. It was around 130 pounds but that is also with power tilt. Much cheaper to repower an outboard. Think it was $2850 delivered for the 9.9btx with remote control unit and power tilt. Suzuki doesn’t restrict remote model sales like others do which is also nice. When i bought mine it was unique. Now Tohatsu has a new 9.9 with a bigger block and fuel injection too.

Shawn

[thomm225]

Originally Posted by Fore and Aft

Thom225 I hear what you are saying about old engines. Have you had a good look on Craigslist for a new old motor? I found a new old 20hp Yanmar 2GMF for $4000 AU still in its crate. It came from a failed boat building project and had been sitting around for years.
I wonder if you could put a custom fibreglass box under that tiller for an outboard? Nothing wrong with outboards, but I just hate the way they detract from the sweet lines of a yacht. Plus less chance of the prop coming out of the water in a chop.
That Viking looks a nice yacht.
Cheers

Well from what I can tell the Viking 33 is a nice boat but this one needs everything.

The first thing is to remove the rusted out engine and old smelly gas tank and old hoses to get rid of the gas smell onboard

Then all the running rigging needs to be replaced.

The sails are probably all well worn too.

The bimini and dodger are old and starting to rip.

Cabin sole will not come up easily. I was afraid to force it when I inspected the boat with the owner's wife not wanting to splitter the boards

Everything needs paint both inside and out

I went through much of this on my present boat when I bought it in 2011 after it sat on the hard for 5 years, but it had much less rust. Almost none.

I could get a nice rebuilt A4 from Moyers, but that is still a 40 year old engine. If I go for a diesel I'll have $15,000-$20,000 in an old boat before I even get started

https://moyermarine.com/mmi360/r1.html

And thinking about it, I'd hate to mount an outboard on a boat this size. It can be a nice looking boat if brought back properly, but that would take a lot of work.

The one I have now is close but it's been 8 years and $10,000 which includes the bottom jobs, sails, solar, autopilots, running rigging, tiller, interior paint, shades, led interior lighting, brackets, new dodger, mainsail cover, and engines.

I bought it for $2,000