9.9hp vs 15hp High Thrust Honda Outboard & Gasoline in Caribbean

[ArmyChief]

This is a three-fold question.

I know PDQ's have 9.9 outboards on them. I also know a few Gemini's had at least one 40 HP O/B at one time.

If you could mount (I'm sure you could) two O/B's on a Gemini. Only motoring to achieve about 5-6 knots. Would your fuel consumption be less with the twin 9.9's or twin 15's? I've looked at the weight difference. The 15 hp's are 8 lbs more each.

This brings me to the next question. How difficult is it to get gasoline in the Caribbean vs Diesel?

Lastly, I've searched and read this forum on storing gasoline on a boat. The venting, the insurace and regulations (not applicable to outboards). Could the existing Gemini fuel tanks be cleaned and used for gasoline. If so, is the venting adaquate you think?

TIA

[TexSail]

High quality gasoline is available in most, if not all of the Carribean. Shell, Esso, & Texaco are pretty common sights.

[capt_douglas]

As for the 9.9 vs 15s, I think the biggest difference is rejetting of the carbs, if your OBs are not fuel injected. I tend to think that a 9.9 running hard would use as much fuel and possibly more than a 15 running mid-range. The other consideration is that the 15s may put you above the 5-6kts you're looking for.

Maybe tank venting but I'd certainly want to add some non-sparking fans into the compartments where the tanks lie and make sure there are no holes for gas fumes to get into the bilge and other parts of the boat.

Finally, I'd make real sure those OBs were very securely attached to your boat. That might be difficult as if I were running OBs, I'd want a way to get them out of the water when I was under sail to reduce drag and prolong their life. Outboards have a tendency to go walkabout in some anchorages.

[ArmyChief]

Originally Posted by capt_douglas

The other consideration is that the 15s may put you above the 5-6kts you're looking for.

I was thinking I may not be able to keep the 15's RPM's up enough not to lug the motor...and be effiecient at speed.

However the original motor in a Gemini is a 27 HP. Two 15's should be about equal.

I hear ya about the security issue. Ashame we have thieves in this world

[captainKJ]

gas stations on land are close by also in most of the islands,,,, we ran out of gas once in a tender and traded a box of steaks for 5 gallons at a restaurant. most of the bahamas people are great in helping you out

I prefer a 4 stroke engine (15) compared to a 2 stroke (9.9)

also consider a chain for the outboard,,, maybe new york bicycle lock

friend of mine had an anchor stolen at night while they were anchored,,, locals cut the anchor line and took the anchor,,

also friend lost a 28 foot intrepid tied to the back of a 150 foot private yacht,, they found it 2 days later run up on the rocks

[VirtualVagabond]

If you're looking at Yamaha 9.9s, they're brilliant, reliable, and seem to only sip fuel, even at high revs. I had 2 on a 45ft houseboat for years and even with all that windage they coped fine. When I bought them I was replacing 2 old mariner 25s so was very concerned about the drop in hp. Only difference was a few seconds longer to get up to hull speed.
Don't have experience with the Honda, but their reputation is also very good.
Vic

[dskira]

Originally Posted by VirtualVagabond

If you're looking at Yamaha 9.9s, they're brilliant, reliable, and seem to only sip fuel, even at high revs. I had 2 on a 45ft houseboat for years and even with all that windage they coped fine. When I bought them I was replacing 2 old mariner 25s so was very concerned about the drop in hp. Only difference was a few seconds longer to get up to hull speed.
Don't have experience with the Honda, but their reputation is also very good.
Vic

I am glad you mention that about the HT Yamaha.
I am on the market to buy one, and I was wondering how's they work.
I am reassured. Thank you.
(it is for my own small houseboat I am building now.)
Daniel

[ArmyChief]

Since the weight is comparable. What about the difference in size? With the 8700 lbs of a Gemini and it originally having a 27 HP motor..In your opinion, do you think it would be "better" to have twin 15's..so you have 4 stroke vs 2 stroke, additional power if needed...would the fuel economy be comparable or better (cause you are using a 4-stroke and at a lower RPM to motor-cruise)

TIA

[captainKJ]

the 15 4 stroke is going to be quieter and NO mixing of oil

[shipofools]

Originally Posted by VirtualVagabond

If you're looking at Yamaha 9.9s, they're brilliant, reliable, and seem to only sip fuel, even at high revs. I had 2 on a 45ft houseboat for years and even with all that windage they coped fine. When I bought them I was replacing 2 old mariner 25s so was very concerned about the drop in hp. Only difference was a few seconds longer to get up to hull speed.
Don't have experience with the Honda, but their reputation is also very good.
Vic

Ditto on the yamaha 9.9 4strokes. The high thrusts are just different props. Easier to get parts than the hondas internationally and more mechanics are familiar with them in my experience as well.

[ArmyChief]

Thanks all

[clockwork orange]

Im not sure where the talk of 2 stroke 9.9s comes from but given the choice i would go for a pair of high thrust 9.9 yamahas 4 strokes over a pair of Honda 15s any day,thrust is what you want on a heavy boat.
Steve.