Ozeam 8hp, Yamaha F6 copy? Small SIB upgrade on 6hp

[Warlock]

Has anyone seen or used one of these-

https://www.thenauticstore.com/en/outboard-motors/210-outboard-motor-ozeam-8hp-4-stroke.html

It seems to be a copy of the Yamaha F6 but must have an updated carb, the Yamaha has the bigger 139cc block and so could it be upgraded to a genuine 8hp?

I have a Suzuki DF6A, it also has a bigger block 138cc, Does anyone know if I could get more than 6hp from this engine?
It almost gets my 3.5m sunsport 350wb kayak on the plane (11mph) but needs just 1 more HP I think!

I have got two different lower pitch props to try though and I’m hoping changing prop pitch may help, has anyone done this with success on a 6hp?

My usual load is 180-190kg (me,wife,3 yr old son)

Thanks in advance for any light that can be shed on my planing dilemma

[Richd]

You're asking a lot from such a small engine! I've got a similar narrow 'crossover' boat so understand the appeal.

I think the only way to get more horses within your weight limit is 2 stroke. The Revered Yam 8 or the Unicorn (Tohatsu 9.8) are both 27kg. There's the possibility of a Selva 8hp 4 stroke which may well be what that engine above is; a Yamaha 6-based clone but I can't see any decent reviews of it. All the other 4 strokes go to 2 cylinders and much more weight above 6hp

[Warlock]

Thanks for the reply, I had a tohatsu 9.8 3-4 years ago but stupidly sold it
I agree it would be the best solution but they are quite hard to come by, also 2 stroke is extremely damaging to marine life, so I feel like I’m playing my part by using 4 stroke, better economy too

So my transom says it’s rated for 40kg and 6hp Max, why I went for a 6hp but would you say it would be ok to put a 37kg 9.9hp four smoke on there?

What canoe crossover have you got please?

[Richd]

I personally wouldn't go for something that heavy whether or not the transom could handle it.

I have an Elling K430SL rated to 10hp/38kg. But we carry less weight so a 20kg 5hp works well with it. It's lovely lightweight and small. I personally would not want to lug anything heavier than 27kg around. My dad has that same Suzi 4T as yours but 4hp (same weight) and no way would I want to move anything any heavier or more awkward than that.

[Richd]

Also, as well as trying a different prop, optimise the transom height: anti cav plate like is being discussed on here at the mo, and the 6 might well do it.

What's the hull like on the SunSport, flat or V? Google does not know!

[Warlock]

I have moved the motor up on the transom by an inch using a piece of wooden baton, did the same on a zodiac I once had, it has definitely improved things, when at WOT the engine is bogging and just won’t accelerate any more, so I am hoping the lower pitch props will work.

The boat feels like it’s just on the cusp of planning and we did actually manage it using some waves and going with the tide, it was intermittent at best.

Another thing I’ve noticed is how much the stern digs in, it just seems I need a tiny bit more RPM of more lift at the back, I’ve also been looking at the small engine hydro foils but not sure i’d Have enough power for one? I am 95kg so I guess it is a stern heavy set up!

I looked at the narrower crossovers but was put off by small tube Diameter but I would imagine I would have an easier time planning due too the narrowness of the boat, mine is 150cm beam at the back.

[Warlock]

Sorry yes it is a flat hull and I have had the pressure inflated a little above recommend pressure