Originally Posted by dirtrider212002
hi there thanks everyone for comenting. the boat i have got is a wooden floor and when it is pumped up to corrct pressure is realy suprisingly rigid. i am new to boating but would be very very cautious so i dont think that is an issue. if i was to go for this 15hp would i be able to use it on my own or would it be to powerful or just throttle on gently.
See first if the 15 HP weight is compatible/safe for the 2.90 transom, this information must be in the sib's owner manual tech specs. Or ask the dealer about it. Is not the same, 3 boys up than 3 adult up, probably a 2.90 with 15 HP driven by 3 boys will fly compared to same 3 adults. Is a matter of accelerating to see/experiment sib's behaviour at different speeds. Would be advisable to adjust a bit the engine steering friction bolt to have a light heavy steering if going for a 15 HP engine. If too light you can lose tiller/sib control. A 15 HP is theorically 3 times faster on calm waters than your actual 05.
Back in 96 used to own a OMC (Zodiac 3.05) with a Evi 10 HP, the top HP the boat could handle, modified the engine to 15 HP and performed much nicer, that is, better hole shot with more weight and slight better end speed. On the other hand if you buy a 15 HP will be perfect for a larger sib update up to a 3.30 mtr.sib. Go for it, but use with caution untill you are confident to have mastered the small beast.
Some Ribnetters will prob say "how can I recommend a newbie to go for a larger engine" so, if possible go with the 15 HP current owner on a engine/sib sea test on calm waters to see/feel it's performance at different speeds before buying. I'm sure in a short trial will be used to the new engine/sib configuration. The final decision is entirely yours.