Biggest engine for SIB

[Brunedaprune]

Hi there, I have a 2.7m air deck SIB. I also have access to get an extremely good deal on a 15hp Yamaha 2 stroke outboard. Would this be a suitable match or is it stupidly overpowered?

[chipko]

Correct answer stupidly overpowered.

However, if it was me, I’d probably risk it.
Assuming at that size rated to 8/10hp at which a modern four stroke will be mid 30 kilos anyway, and at 36kg the Yamaha not much heavier. Just exercise caution with the go faster handle!

The engine’s a cracker so go for it. You can always upgrade the sib at a later date if it’s too hot to handle. [emoji3]

[Brunedaprune]

I also have a pathetic 4hp evinrude so I thought I might be able to swap the 4hp with the SIB for a RIB that’s a bit bigger. Does anyone have any experience on aluminium skiffs, I’ve had awesome memories with them but I can’t seem to find any little ones for less than a few thousand.

[Fenlander]

I might have a different opinion to many in that the biggest OB you can strap on isn't always best. An over power and/or over weight OB can unbalance the feel of an outfit so I'd say if you were keeping the 2.7 and that was the purpose of getting the 15 then perhaps look at a lightweight 10hp instead. If you think you might soon upgrade to a bigger boat then perhaps that might suit a 20 and then the 15 is no use.

[Pikey Dave]

Originally Posted by Fenlander

I might have a different opinion to many in that the biggest OB you can strap on isn't always best. An over power and/or over weight OB can unbalance the feel of an outfit so I'd say if you were keeping the 2.7 and that was the purpose of getting the 15 then perhaps look at a lightweight 10hp instead. If you think you might soon upgrade to a bigger boat then perhaps that might suit a 20 and then the 15 is no use.

Absolutely[emoji106] My default setting for RIB engines is max the RIB will take (plus a bit for good measure) SIBs are a completely different kettle of lobsters. You need to be able to manhandle the engine for a start, & as you say, SIBs are more sensitive to weight than RIBs.

[beamishken]

Originally Posted by Fenlander

I might have a different opinion to many in that the biggest OB you can strap on isn't always best. An over power and/or over weight OB can unbalance the feel of an outfit so I'd say if you were keeping the 2.7 and that was the purpose of getting the 15 then perhaps look at a lightweight 10hp instead. If you think you might soon upgrade to a bigger boat then perhaps that might suit a 20 and then the 15 is no use.

A 15hp Yamaha 2t is exactly the same engine as a 9.9 2t & a 20 is way heavier the 15hp he's been offered is a great engine power to weight wise if its a good deal then he'd do well to grab it & fit to a larger boat when he can.

[Blankton]

The 15hp and the 9.9 are the same engine apart from one piece, so no concerns with regards to weight or transom strength etc. I have a (removed) throttle restrictor in my shed if you'd like to downrate it

It may be a bit scary on such a small boat, but you don't need to give it full beans. If it is too much, I'd probably look to buy a slightly larger boat, as they are very good engines!

[Fenlander]

Of course much of the answer to this depends on the use this 2.7m Sib is being put to... long voyages like The Gurnard... messing about in the breakers just offshore... a brief tender journey dropped over the side of a yacht using the boom etc.

[Brunedaprune]

Not too sure about its role will decide how well it handles the swell. Does anyone have any idea what I could expect with a 25litre tank and a 70kg lad for speed wise. Only way is to test it out…

[Steve509926]

Maybe the choice of the 15 or something smaller could be decided upon, by where you normally launch in Anglesey and how often?

[Brunedaprune]

My mate got rid of the yam to someone else, but I got his 9.9 mariner 4 stroke for a case of beer. All it needs is a whole new lower unit and new carb. Does anyone know where the best place to sort these parts are?

Ta

[Blankton]

Originally Posted by Brunedaprune

My mate got rid of the yam to someone else, but I got his 9.9 mariner 4 stroke for a case of beer. All it needs is a whole new lower unit and new carb. Does anyone know where the best place to sort these parts are?

Ta

That's a shame that you've lost out on the 2 stroke, your mariner probably weighs more, for less power!

You see a lot of ob's being broken on ebay, but gearboxes aren't cheap. £150-300 is the range I see. Carb wise, you could try a rebuild kit for a few quid, buy a Chinese pattern part for about a hundred or a genuine one for even more.

[Brunedaprune]

Depending on what I think of the engine. I also have the option to get a big old 25 mariner 2 stroke. But that will probably warrant a rigid floor boat.

[tinker]

Originally Posted by Brunedaprune

Depending on what I think of the engine. I also have the option to get a big old 25 mariner 2 stroke. But that will probably warrant a rigid floor boat.

Be a fun day out on 2.7m SIB, just make sure you wear a lifejacket and kill cord, action camera strapped to your head, the youtube video would probably pay for a whole new setup

[Fenlander]

Do you know the history of this Mariner 9.9 as to why it needs a carb and gearbox? As Blankton says replacements even used are expensive so I’d have a concern that you need to know the rest of the outboard is good enough to justify sourcing these parts.

[Steve509926]

If you're mostly launching on Anglesey, it would be cheaper to have a sub 10hp otherwise you will be paying £10+ every time you launch.

[Brunedaprune]

Am in Trearddur bay, boat will stay on private beach with engine in nearby neighbours shed with fuel tank. I’ve seen engine running before. A lower unit was needed urgently for another boat so it was taken off mine and just left in a corner. I’ll need to actually pay a fair price for the 25 mariner so it makes sense to run the 9.9 for a summer and save up some money. But at the end of the day, the best type of boat is the boat you can use.

[Steve509926]

Lovely part of the country, had a great couple of weeks there last year. Planning on a couple of weekends back there over the simmer.