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I have a BF20 that's on a trailer sailer that I've been given and am trying to sell (http://www.trademe.co.nz/Browse/Listing.aspx?id=891439399). Seems like a really nice motor for the few times I've used it. 6amp charging as standard and can be upgraded to 12amp I think? If you want to help unbolt it, your welcome to borrow it to see how it fits and goes. I'm really hoping I can sell the boat without the motor as I really want to keep it for cruising on Freedom/hooning around in my RIB. 

 

Mine seems to have a smaller prop than the 9.9 yamahas run so that might be a point of difference. I don't know if mine is a high thrust model.

 

I think I remember Phil saying Sundreamer has one of each at the moment and he is trying to go back to the yamahas?

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I've had two Honda's on Pulse. First one was a 15 hp, the old square model as it was the last one to be upgraded into their current form. It was a very good and reliable engine. A year overseas and not getting used probably killed it, eventually getting gear box problems and a cracked water jacket. Still it did nine years without getting flushed of course. 

Then there was a 15 hp 'Sail' outboard. It was called a 'Sail' because mostly that is what I did as it was hopeless. Stay well clear.

Now I have a 10 hp Honda, only because there wasn't a 15 hp available in the country just before a Coastal when I needed to replace the above quickly. It has an impressive 12 Amp charging and electric start. It's been mostly reliable, a few niggles. It has a vibration at mid revs, but could be in the boat. I miss the extra 5 hp only when going from forward to reverse. I've got the biggest 4 blade prop with fine pitch I could find.

On the whole I've been more than happy with the Honda's I've had.

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Only decent picture I could find! Just in response to the Accord comment above it really.

 

I once had an outboard called a Wind 8hp, was made in Russia by a company called Volga motors (seriously). Fantastic motor, ran like a dream once they replaced the faulty ignition coil they'd all been shipped with! If I still had it, I'd be using it!!

 

Apparently the Wind was more reliable than Tim's Sail :)

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an old thread

 

but have been researching prop specs

 

as previously stated

 

the yamaha 8hp 2-stroke is a high power, low weight,  popular choice for 8.5mt multis

 

it comes standard with a large pitch 10'?  all white prop designed to get light dinghies planning

 

there are also 2 lower "geared"  "dual thrust" options for boats heavier than a dinghy that will never reach those speeds

 

the black hubed  9" x 7"N, for light weight multis (9 inch diameter with 7 inch pitch)

 

 (cast into the prop alloy)

 

and the black hubed 9" x 5"N for heavier boats with heavy keels

 

the black hub is "dual-thrust" in yamaha speak, which means in-hub exhaust so the blades are less likely to cavitate in reverse and lose bite.............most light tinnys/inflatables etc don't reverse much so don't need this exhaust gas diversion

 

solas also make 5 props for the yami 8hp 2 stroke, the 4 bladed versions with in-hub exhaust probably the best choice for multis

 

http://www.rubexprops.com/boat-propellers/Yamaha/?motor=H0080C&ver=a&model=8HP%202%20Stroke%20(7%20Spline)

 

yachts heavier than 900kg probably want more power AND lower gearing

 

for them the 9.9hp was made with lower reduction gearing to prop (planing speeds not needed)

 

AND a range of dual thrust props for differing boat weights

 

..............

 

cavitation protection in swells

 

small multis with a single outboard mounted centrally seem better with the long shaft engines as the hulls can lift the prop out in swells + waves

 

yamaha make just the 1 long shaft option but tohatsu make a long and an extra long

 

as Greg has on Mysterex

 

but even the standard long shaft yamaha can still get lifted clear enough for the engine to scream as the prop half spins in air.......one way to help prevent this is to bolt an aftermarket hydrofoil to the engine's small anti-cavitation plate just above the prop

 

194156799.jpg

 

http://www.trademe.co.nz/motors/boats-marine/parts-accessories/outboards/auction-1168791372.htm

 

the barnys fitted 1 to capricorn's 8hp 2-stroke yami

 

gallery_1988_37_413454.jpg

 

and it seems to be working well

 

they are just a cut + bent bit of alloy sheet so am going to knock up another out of some spare ally checker-plate for the spare engine

 

also outboard mounts that have multiple down positions help to keep the prop from spinning free

 

capricorn is set so the 2nd from bottom hole for motoring off the mooring, with sails already raised

 

but need the max bottom setting for motoring in, as when head to wind to drop sails, my weight moving from stern to bow, can lift the prop clear from the 2nd from bottom position

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It's not cavitation. It's ventilation. Air being sucked down to the prop from the surface. 

Cavitation is very unlikely on the small outboards and speeds we operate at. 

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