repowering dinghy

[jwilsail]

I have a 10' rib with a 15 hp 2 stroke Tohatsu. I am thinking about repowering with a 4 stoke but I don't want to increase the weight too much. The current engine can push me at 20 knots. I don't need to go that fast. I am considering going down to a 9.9hp. Has anyone done this and were you happy with the result?

 

[Ski in NC]

I have run a few four stroke 8 and 9.9's, some merc, some tohatsu, some yammi. Also run similar hp two strokes. And own a 8hp merc two stroke. I BY FAR prefer the two stroke in this size. Smoother running, lighter, easier to pull start. The four stroke two cylinder is an infernal beast balance wise. And the carbs are a pita to clean compared to the two's.

Sure they burn less fuel and don't smoke, but in my opinion, the disadvantages outweigh the advantages. Once you get to say 30-40hp and get a three cyl, then it all changes.

 

[jwilsail]

Sounds like I might be better off just getting a tune up for my 15hp 2 stroke.

 

[caltexflanc]

Sounds like I might be better off just getting a tune up for my 15hp 2 stroke.

Correctomundo.

 

[gaston]

I hate my Honda 10 HP it dose start every second pull but you gotta be standing to start it . Going back to a Yammy 15hp 2 stroke very soon when warm they start on 1/2 a pull.

 

[Nomad Willy]

Was wondering when this would happen.
I've got four two stroke outboards.
2, 4, 6 and 8hp
Yup I like um.
I run 40-1 mix.

 

[Dougcole]

Don't get rid of your 2 stroke, you will regret it if you do. Small four strokes suck, especially on a rib.

 

[drinkenbuddie]

I have had a few too. Right now I have a 5 merc and a 9.9 yam two strokes and 3.5 tohotsu 4 stroke. Love the 3.5 on my gheeno but the 9.9 on my ding.
Yes two strokes are way lighter but love the quite of the fours.

 

[Bay Pelican]

The four strokes have improved somewhat in the last 10 years but I have met several boaters who found out too late that their wives could not pull start 9.9 hp four strokes. If you are a cruiser where your first mate will use the dinghy then make sure she can start any outboard you are going to buy.

In the Eastern Caribbean where both two strokes and four strokes are sold the four strokes are rarely bought in the smaller sizes.

 

[angus99]

The four stroke two cylinder is an infernal beast balance wise. And the carbs are a pita to clean compared to the two's.

Sure they burn less fuel and don't smoke, but in my opinion, the disadvantages outweigh the advantages. Once you get to say 30-40hp and get a three cyl, then it all changes.

At the upper end of the "small" outboard category, does anybody have experience with the 15-20 HP Suzukis? Fuel injected with no need for a battery and both engines at or below 100 lbs. Thinking about one for our next dinghy, which won't be a RIB.

 

[Nomad Willy]

My wife loves our 6hp Johnson. All controls are easy. Starting, steering, shifting and throttling. Re the latter it's not abrupt .. very controllable .. unlike our 60hp Suzuki.

 

[jleonard]

Sounds like I might be better off just getting a tune up for my 15hp 2 stroke.

Yes you are. Keep it till it pukes.

 

[gaston]

At the upper end of the "small" outboard category, does anybody have experience with the 15-20 HP Suzukis? Fuel injected with no need for a battery and both engines at or below 100 lbs. Thinking about one for our next dinghy, which won't be a RIB.

Suzuki 15s are ok but why fight science and why have fuel injection on a small motor with all the inherent problems that come with it .Just buy proven Yamaha 15hp
If you wish to save a few $$ buy a Yammy 9.9hp and fit a 15HP reed valve this makes the 9.9 a 15

 

[mbevins]

Suzuki 15s are ok but why fight science and why have fuel injection on a small motor with all the inherent problems that come with it .Just buy proven Yamaha 15hp
If you wish to save a few $$ buy a Yammy 9.9hp and fit a 15HP reed valve this makes the 9.9 a 15

I wouldn't give up my 15hp Yammie for anything. Bought it when my merc started acting like a POS. That was 12 years ago. Keep the 2stroke.

 

[Mule]

At the upper end of the "small" outboard category, does anybody have experience with the 15-20 HP Suzukis? Fuel injected with no need for a battery and both engines at or below 100 lbs. Thinking about one for our next dinghy, which won't be a RIB.

I have a 15 with electric stare,.....love it...no carb problems...no carb..

 

[HopCar]

Lehr 9.9 and 15 are available with electric start for those, like me, who are to lazy to pull the rope. The neat part is that the battery is under the engine cover. No cables needed. I have a Lehr 15 on a little skiff I built and I love it.
I do have to tell you I'm a Lehr dealer so I may be biased.

 

[Giggitoni]

I'm too lazy to check the charts...but I think the 15 and 9.9 four strokes are about the same weight; no gain there.

Edit: couldn't stand myself! The Honda 9.9 is about 12 pounds lighter than the 15. 92 vs 104 pounds.

 

[HopCar]

In two cycle engines I think you'll find that 9.9 and 15 are the same weight. In four cycle engines the 9.9 is generally lighter.

 

[Bay Pelican]

My Johnson 9.9 two stroke weighs approximately 62 lbs. The Honda 9.9 four stroke mentioned above weighs 92lbs. Quite a difference in being able to lift it with one person.

 

[DavidM]

In addition to all of the good advice above to keep your two cycle, a four cycle 9.9 hp outboard may not plane your boat. I had to put a flatter pitch prop and a Doel-Fin on a Tohatsu 2 cycle to plane a similar dinghy with three people aboard. A 4 cycle should be worse.


David