converting a 9.9 yam to a 15

[willfinch36]

I have a 2002 Yamaha 9.9 2 Stroke, so what EXACTLY do I need to do/parts would I require to tweak it to a 15?

Cheers

Will

[willfinch36]

Someone must know??

[Max...]

Worth putting the topic title into Google as it brings up lots of other similar discussions, one below:

Yamaha 9.9 to 15 hp

[kdaw]

Originally Posted by Hugh Jardon

I have had a couple of questions regarding what it takes to upgrade a 9.9 yam to a 15

here goes

i have attached a pic of my particular engine, you will note the engine plate on the side of the engine as Steve cant find his so this is where it is on my engine. this modification was done on this style of engine rather than the older squarer ones

the next pic is me pointing to a metal stop that restricts the throttle from opening more than around 60%

if the background you can see the gold colour of the reed block, this is just bolted in place between the block and the carb

took me around 20 mins to do the work and that included a t-break

another pic of the engine from the side.

costs were as follows

bending the throttle stop out the way ....free

buying a new 15hp reed block....around 28 quid

buying a new 15hp sticker for the front and back.....around 2.80 each

i purchased a 12 pitch prop to take advantage of the extra power....50 quid

the benefit of the 50% increase in performance and increased economy....priceless

it is amazing how much more these reeds open compared to the 9.9 item

well worth doing

I know it's an old thread but

Guys I have a 3hp Malta but it also has a stop just like this one, I have started it up and it has a full throttle , does this mean that maybe this could be the 4hp version but it's restricted??

Thanks Karl

[phantom 19]

Originally Posted by kdaw

I know it's an old thread but

Guys I have a 3hp Malta but it also has a stop just like this one, I have started it up and it has a full throttle , does this mean that maybe this could be the 4hp version but it's restricted??

Thanks Karl

Nope the Malta is 3hp there is no restriction / limiter on the carb.

Although with age I have found that somehow maltas can suffer from spun liners which does cause restriction by partially closing off the exhaust port