Newbie Q - What outboard for a 3.1m RIB?

Clin Hoolihan · 05 February 2008, 15:43

I've been floating around on the peripheries for some time just lurking and eventually decided to take the plunge and ask, regardless of whether it sounds stoopid!

I am awaiting delivery of a 3.1m RIB for just cruising and family fun etc.. (15hp max in the spec).
I've spent hours looking around on the net at different sites for outboards (new) but I reckon the water's getting muddier. Should I be looking at a 9.9hp or a 15hp, I do want a four stroke with a short shaft, that much is decided. Wondering between engine weight and size is driving me round the twist.
Has anyone any experience to share with me regarding what to go for between those two engine sizes.
I know I'll probably look back on this question in the future and realise how dumb it may sound but I am very very green, bear with me please.

9D280 · 05 February 2008, 16:29

If you know you want a 4- stroke, then I guess the toss - up is between having that extra oomph and getting a hernia lugging an extra 10-15 KG up the beach.

If it's any help I've used an OMC Express 3.1 (not too dissimilar to your new toy) with a two stroke 8Hp on the back. Went like a mad thing 1 or 2 up, 3 or more (adults) it struggled to plane.

I suppose it may depend how you plan to get it to & from the water - if you are on a trailer or will always be able to park a few yards from the shore, go for the large one, if you have to lug it across half a mile of sand to get back to the car every time, I'd be tempted by the lighter one. Also if you're deflating or car topping the hull, check the size in the boot when you're at the dealer - Small outboards have an annoying habbit of growing when you show them a car boot, and if you have the whole family with you, that space will likely be at a premium!

Some food for thought - hope it's of some help, there are lots of SIB owners on here who I'm sure will be along shortly to add to the discussion......

yoyo · 05 February 2008, 16:36

15hp two stroke is the way to go for performance and family cruising IMHO.

shirehorse · 05 February 2008, 16:43

I have owned the 10 hp honda and now own the 15 hp they are worlds apart in performance and you dont really notice the weight difference. If you can manage the smaller you will cope with the bigger imho.

K&S · 05 February 2008, 17:02

Hi, we have used a suzuki aux on our previous boat and liked it so much we bought a larger suzuki for our new boat which was a shift away from mercury which i would have advised before now. (not that there is anything wrong with them)

Anyway have a look at the Suzuki 9.9 and 15 youll find they are the same weight so based on that and the fact you can allways slow an engine down but not speed it up without altering the engine i would recomend the 15hp

Cypman · 05 February 2008, 17:59

I believe that all the major manufacturers eg Honda,Suzuki,Yamaha and Mercury produce reliable quite similar products in the 9-15HP ranges. Furthermore, the weights of their 15HP models vary from 47.5kg to 52kg so there is little to choose between on weight criteria. So IMHO I would seek the best deal you can get, with this in mind Tohatsu may be worth looking at, they are very good value. If you are willing to consider a 2-stroke, Tohatsu can provide a 9.8HP weighing in at only 26kg whilst their 15HP 2-stroker is only 41kg, and a lot cheaper than a 4-stroke. I have no connections with Tohatsu!!!

blinddog · 05 February 2008, 20:35

We use a 15 hp Yam ( 2004) fourstroke on our 4 mtr inflatable, its the same block as the 9.9.
It gets up on the plane easily and is fantasic on fuel, we cannot fault it.
gaZ

codprawn · 05 February 2008, 20:41

I have a 15hp Suzuki 4 stroke on a 3.1m and it's great but I would rather a 2 stroke. They are easier to carry - give more grunt and easier to transport(lie it down any old way).

The 18hp Tohatsu is the same weight as the 9.9 if I remember correctly.I would always go for the biggest engine you can in the same weight range.

Unfortunately small 2 strokes are vanishing fast so if you have to get a 4 stroke go for the cheapest deal they can - all the makes are prob as good as each other.

Downhilldai · 05 February 2008, 20:46

Quote:

Originally Posted by yoyo

15hp two stroke is the way to go for performance and family cruising IMHO.

Quote:

Originally Posted by Cypman

.... If you are willing to consider a 2-stroke, Tohatsu can provide a 9.8HP weighing in at only 26kg ....

Quote:

Originally Posted by codprawn

I have a 15hp Suzuki 4 stroke on a 3.1m and it's great but I would rather a 2 stroke. They are easier to carry - give more grunt and easier to transport(lie it down any old way).....

ian parkes · 05 February 2008, 20:59

If its a 4 stroke for sure then check all the manufacturers for the wieght of the motor . Wieght has to be the most important factor or lack of it .

the honda 20 was by far the lightest in a 20 also available as a 15 but somebody may make a lighter 15 4t now.

ADS · 05 February 2008, 23:53

Yamaha 15 2 stroke or Tohatsu 9.9/ 18hp for me, I wouldn't bother with a fourstroke on something that size, the additional weight, pain to store and I doubt the fuel consumptions drastically better. 2 stroker should be cheaper to purchase too and you can't beat the smell first thing in the morning.

Tim M · 06 February 2008, 00:02

I too would get a decent used 15-2stroke. I bought a Mariner 15 2-stroke just before Christmas and its an amazing little engine.

Nos4r2 · 06 February 2008, 00:13

Quote:

Originally Posted by codprawn

2 stroke. They are easier to carry - give more grunt and easier to transport(lie it down any old way).

Well, sort of. Must remember that you can't let the prop get higher than the powerhead and to let it drain down for a while before transporting so water can't run back up the leg.

Loads easier than transporting a 4 stroke though. I'd buy a 2 stroke in preference.

ian parkes · 06 February 2008, 00:24

I notice on my tohatsu 3.5 it says to keep the prop below the powerhead .
what is the reason for that ?, apart from water not draining out .
can the gear oil get up into the motor somehow .

i wanted to lay the motor down on its side in the consul so it could get tilted up at times

Nos4r2 · 06 February 2008, 00:34

Quote:

Originally Posted by ian parkes

I notice on my tohatsu 3.5 it says to keep the prop below the powerhead .
what is the reason for that ?, apart from water not draining out .
can the gear oil get up into the motor somehow .

i wanted to lay the motor down on its side in the consul so it could get tilted up at times

Water will run up the leg and into the cylinder via the exhaust port if you have the prop above the powerhead. Only takes a drip of salt water to seize an engine.

ian parkes · 06 February 2008, 00:49

Quote:

Originally Posted by Nos4r2

Water will run up the leg and into the cylinder via the exhaust port if you have the prop above the powerhead. Only takes a drip of salt water to seize an engine.

Thanks mate that didn't occur to me at all , but it so bloody obvious really innit

Locozodiac · 06 February 2008, 01:49

Quote:

Originally Posted by Clin Hoolihan

I've been floating around on the peripheries for some time just lurking and eventually decided to take the plunge and ask, regardless of whether it sounds stoopid!

I am awaiting delivery of a 3.1m RIB for just cruising and family fun etc.. (15hp max in the spec).
I've spent hours looking around on the net at different sites for outboards (new) but I reckon the water's getting muddier. Should I be looking at a 9.9hp or a 15hp, I do want a four stroke with a short shaft, that much is decided. Wondering between engine weight and size is driving me round the twist.
Has anyone any experience to share with me regarding what to go for between those two engine sizes.
I know I'll probably look back on this question in the future and realise how dumb it may sound but I am very very green, bear with me please.

Hola Clin

In order to help you better, why don't you specify the way you will launch your rib, is it going to be carried to the beach, place the engine every time you will use it, will you use a nice trailer with the engine secured to the transom and straight to water ? This is like day & night, the first option will drive you extremely mad after some launches, unless you have a very nice and cooperative crew with the sib owner.

Personally would not buy any 9.8 HP because if you change for a larger rib like a 330/340/350/ you will repent having purchased a small engine. If you must buy a new engine buy one that can support your next size sib/rib so not to sell the previous small engine, loose money, put the $ price difference to buy the second you should have bought in first place. An engine is a family leisure investment, so invest accordingly. Had a Evinrude 15 HP 2 strokes for the past 10 years and have updated 3 size sibs witht the same engine in ranges of 305/320/330, now moved to a Tohatsu 18 HP to power my new Sea Rider 360 sib. A proyect that have slept for the past 6 months because of trailer manufacturing problems.

If you must suffer carrying the engine to the boat go for a 15 HP 2 stroke. As my grandmother says " Better is to have more and don't need it than to have less when you need more" Anyway an engine can be carried by two people and definitely will enjoy the extra power performance.

Tohatsu has a nice 18 HP 2 strokes engine that weights the same as the 10 & 15 HP that is 42 Kg so this model will be a nice option to a 15. Four strokes are about 10 Kg heavier for that same 2 strokes model. If you will use a trailer and 2 strokes engines are not available in you area because of polution control, go for a 4 strokes then.

And don't be shy to ask whatever info you need, that's the purpose of the forums and Ribnetters are very cooperative cool guys !!

Happy Boating

Nick Hearne · 06 February 2008, 11:47

I have the 15hp Yamie it's 36kg I think & plenty to be carting around!
The wife is quite happy using the boat with the kids which is a + & the gear leaver at the front makes life a lot easier!

All in all very happy with it.

Clin Hoolihan · 06 February 2008, 18:36

Must say I'm bowled over by the responses, thanks everyone.

Locozodiac, I will be wheeling it from a boatyard about 50 yards to a slipway, so not much travelling to worry about. I do want it to be manageable for wife and kids (well young adults 16 & 19).

What is this I am hearing about not being able to buy two-strokes etc.... new legislation?

Once again, thanks everyone.

Nos4r2 · 06 February 2008, 19:11

Quote:

Originally Posted by Clin Hoolihan

What is this I am hearing about not being able to buy two-strokes etc.... new legislation?

Sort of. Importing of new carbureted 2 strokes for leisure use is banned (or something like that).

The upshot is,they ARE still available-while current stocks last-so if you want one, grab one. The spares/dealer network etc will still be available. I wouldn't be surprised if they hold their value rather well too as they are in demand because of the better power/weight ratio.