Outboard for 2.9

tuskar · 26 October 2015, 20:00

Hi all,
I have a 2.9 excel with an 8hp mariner 2 stroke . Considering going a little bigger to a 10 horse power as that is manufacturers maximum rating.
My question is , is it worth changing for 2 horse power would prefer a 15 as they weigh same , if was sensible with throttle and low cargo will the excel last.
Thanks

beamishken · 26 October 2015, 22:46

We had exactly the same boat with a 9.9 mercury 2 stroke & my pal asked me to test a 6hp evinrude which was the same 2 cyl block as the larger hp engines & there was very little loss in performance
So going from an 8 to 9.9 might not give you much improvement
A possible course of action might be buy a yam 9.9 two stroke & try it if your disappointed then it's a fairly easy job to convert to a 15. I think it's just a reed block change & throttle stop to adjust
I'm on the lookout for a 2 stroke 8 hp if your going to sell the 8 let me know

tuskar · 26 October 2015, 23:28

Thanks bearmshken. I suspect a 2 horse might make little difference.just a bit nervous about fitting a 15 to such small 2.9 sib.
Thanks

Max... · 27 October 2015, 08:07

Hi Tuskar, in two strokes a 9.8 would be the popular fitment (especially the Tohatsu at 26kg) and ideal for that size SIB. The issue with a 9.9 engine is that they are generally the same block/size/weight as a 15 so most people would go with that but the 9.8 is much lighter.

As you say a 15 on a 2.9 will be fun but probably not needed.

What sort of use do you have the boat for and in what way do you find the 8 lacking?

Roflhat · 27 October 2015, 09:20

I don't think a 15hp on a 2.9m would be overpowered, is there one you could try on it?

beamishken · 27 October 2015, 09:58

Quote:

Originally Posted by tuskar

Thanks bearmshken. I suspect a 2 horse might make little difference.just a bit nervous about fitting a 15 to such small 2.9 sib.
Thanks

Hi the reason I suggested the 9.9 yamaha 2 stroke is its the max recommend for the boat & it is upgradeable quite easily which would mean the boat was still fitted with a 9.9 for insurance purposes .
I agree that 2hp will make only a small improvement & 15 seems a big jump & while it might be flighty with one person in, it will tame down considerably once loaded so as long as your carefull you'd probably be fine
Fwiw our boat was one of the first imported & 10 years on is still fine & hasn't had any special attention or been particularly loved so id say they are reasonably tough boats & would probably be fine with the 15hp if your carefull

jeffstevens763@g · 27 October 2015, 10:10

i had a zodiac 310 solid rated at 15 hp not much bigger than yours really worked well but you have to be sensible of course as with any boat beamish is right though go for the yam and up rate it to keep you right insurance/harbor laws etc

tuskar · 27 October 2015, 12:24

Thanks for all the advice . I just had fears of shortening the life of my exel
Think ill go 15 and be sensible. I boat on sea in Georges chanell with strong currents and find the 8 a bit wanting with 2 guys on board on rivers it's fine.

Gwozhog · 30 October 2015, 02:37

Get the 15. It's always nice to have both the 8hp if your by yourself and the 15 if your taking buddies out.

lightning · 03 November 2015, 07:28

My 2.85m Zodiac SIB (solid floor, air keel) goes like a rocket with a Tohatsu 9.8 on it, planing pretty much instantly and achieving about 19mph.

That's with two of us on board.
Also as mentioned the motor only weighs 26kg so is easy to carry and well within the 38kg max transom weight.

Before that we had a 6hp Mariner four stroke which weighed the same. Performance was much improved with the 9.8, much easier to plane and 6mph faster (19-20mph) top speed.

I tried a higher pitch prop on the Tohatsu and it did not make much difference, apart from about 500rpm lower at all planing speeds, and a bit more time to get on the plane (instant with the standard prop)

Our boat is rated to 8hp and 17mph.

Above that speed it does become harder to steer.

I think you will notice a fair difference going from 8hp to 10hp, after all it's 20% more power.
It depends on how far the 8hp is from what you want.
I'd look at the Tohatsu 9.8 unless the extra 10kg of the 15hp is not a concern.

tuskar · 03 November 2015, 08:38

I think the tohatsu 9.9 is getting hard to find now. Would be my first choice , may just hold off until one appears for sale.

willk · 03 November 2015, 08:40

Quote:

Originally Posted by tuskar

I think the tohatsu 9.9 is getting hard to find now. Would be my first choice , may just hold off until one appears for sale.

Tohatsu 9.8 is the one, the 9.9 is a heavy pig as is a downrated 15hp.

tuskar · 03 November 2015, 08:45

Thanks again.9.8

Mikefule · 03 November 2015, 17:18

9.9 is 25% more than 8, so that's 1/4 more power. I'd be wary of exceeding the recommended spec for the boat in case you ever need to make a claim, particularly if there is a third party claim against you after an incident.

lightning · 04 November 2015, 19:58

The Tohatsu 9.8 is still available new from a dealer called Mainbrayce Marine.
They get around the ban on small two strokes by selling from the Channel lslands.

There has been much discussion about the ethics of it, but if you want a new Tohatsu 9.8 (and it's in a class of one, being the only lightweight 10hp) they will sell you one.

I bought mine from them back in 2012.

Mickhitchuk · 05 November 2015, 05:02

Guy sells new tohatsu motors on gum tree, he gets then from Bulgaria, not sure on any warranty claim tho

lightning · 05 November 2015, 07:48

Quote:

Originally Posted by Mikefule

9.9 is 25% more than 8, so that's 1/4 more power. I'd be wary of exceeding the recommended spec for the boat in case you ever need to make a claim, particularly if there is a third party claim against you after an incident.

Yes l was wrong, while 8 is 4/5 of 10, 10hp is 25% more power than 8hp

Neil Harvey · 20 January 2016, 21:28

Bit late but I have the same boat and had 16-17 kn one up out of it with the Tohatsu 9.8. Wouldn't have wanted much more to be honest as it seemed on limit in the conditions I was out in.

lightning · 02 February 2016, 07:10

To the O/P

What speeds are you getting on your boat with the 8hp fitted, and does it get on the plane easily?

And how many people on board? As you have a similar boat to mine l could tell you what difference upgrading to a 10hp would be likely to make.

tuskar · 15 May 2016, 21:32

Sorry for late reply gave up off season

. Can just about plane with 2x85kgs with my 8hp maybe its worn and down on power.