More power from Mariner (Yamaha) 8hp

[Lee1]

This is the question guys. . . .
I have an absolutely mint condition 1989ish Mariner (made by Yamaha) 8hp model 6G1 short shaft twin cylinder two stroke outboard with only 30 hours use. I will never sell the engine as it's perfect for my smaller sibs (2.3-2.7) with just myself on the smaller sibs it plans and goes like a rocket but obversely it struggles with 3 persons on small ribs and use on above 2.7 size sibs its underpowered, I don't want to play around with extensive engine tunning like porting as I want to keep the engine original I would re jet the carb but I understand just bigger jetting won't really achieve move power so would a different prop give me more power? The current prop looks like the Yamaha high thrust ones and does not have the split pin method of holding on the prop to the shaft, the prop slides on the shaft and is held on by a nut, I know almost everyone will say get a 15hp but I have one already lol I would like this 6G1 to give me 11hp power

[beamishken]

I doubt your going to get more power easily from an 8hp as it's at the top of it's hp range already
You may manage to plane better with a heavier load with a smaler pitch prop and or a set of doel fins to give you more to plane on

[Fenlander]

As Beamishken says the 8hp is at its optimum already... if you'd had the 6 then that can be upped to the 8 but it's a lot of faff... and expense if new parts are used.

I wouldn't say get a 15 on a 2.7 where you obviously value portability.... but I would say consider a Tohatsu 9.8 2-stroke. Physically and weight wise pretty much the same as your 8hp but with a useful 25% extra power.

3 persons will always be a struggle unless you up the sib size and OB power... so you just need to accept trolling about at displacement speeds.

[Lee1]

I guess I already knew the answer lol thanks guys, a life long spare the 6g1 will be i guess

[Lee1]

Originally Posted by beamishken

I doubt your going to get more power easily from an 8hp as it's at the top of it's hp range already
You may manage to plane better with a heavier load with a smaler pitch prop and or a set of doel fins to give you more to plane on

Thanks, could you give me more info on the prop or a link so I know what I'm looking for thanks

[beamishken]

Looks like standard is 8 1/2×7 1/2 but you can get 8 1/2×6 1/2 maybe worth trying to find the smaler pitch to give a little more grunt I have an 8hp on a rib eye tender and it does seem a little overproped at times with a load in the boat
It would be nice if you could borrow one before you commit to spending 50 quid or so on a new prop