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Old 24 February 2007, 17:09   #11
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Country: UK - Scotland
Boat name: imposter
Make: FunYak
Length: 3m +
Engine: 2 stroke YAM 20 HP
MMSI: 235089819
Join Date: Sep 2005
Posts: 10,114
Quote:
Originally Posted by MustRib View Post
Maybe I ought to get the 25hp Yam and put the hood from the 20hp on top!
Or can you get the cheaper 20HP and uprate it by replacing carbs?

I have the 20HP myself so would be interested to know.

I think you will notice the difference from 15-20HP though (I have no direct comparison as not tried 15 HP on my boat). Its possibly misleading to think of this as adding just 5 extra HP - but rather think of adding 33% extra power.

I don't know how HP varies with throttle on the yam but if it is linear (i.e. 3/4 throttle is 15 HP on the 20HP model) then you WILL notice the difference. On my boat 3/4 to full throttle is at least 5 knots difference in the flat.
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Old 24 February 2007, 18:04   #12
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Country: UK - England
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Boat name: Merlin
Make: RB4 Gemini 550
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thanks for that....
The Yam model is a new - but 2005 2 stroke engine....So any hints and tips that you peeps have on the motor would be appreciated.
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Old 26 February 2007, 19:49   #13
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I had the same boat last year , with a 20 honda .

Get the 25 yam it won't be a problem for sure .
I went for the honda for economy , but the amount of fuel it used was so little I wished at times I had the extra power .

As for speed mine used to do 18 kts flat out with 3 people in , probably 20 plus with one but was very twitchy unless it was calm , so be careful till you get used to the motor and the way it handles .
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Old 26 February 2007, 23:28   #14
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Country: UK - England
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thanks Ian...
I have decided to get the 20hp ...
Will post here when I get it fitted and have had a try (weather permitting!)
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