What Four Stoke

[Jono Garton]

Hi

I'm off to Gurnsey next week to see Jason about the Pro Sport.

Cant decide if I Want twin Yamaha or Mercury/Mariner 115.

Any one got any news on the Yamaha 150hp Four Stoke, is the merc far behind?

Can anyone offer their views? Problems? with either

Suzuki and honda are out due to no local dealers to service.

[John Hughes]

My 115 efi Mercury (my first outboard) on a 6 metre Valiant won't pull more than 4750 rpm, and I am dissapointed with top speed, about 35 mph with light load and calm sea.
Am satisfied prop etc correct, and have been told it (engine) adjusts itself according to load!! It's very quiet, reliable, and doesn't seem to use much fuel, albeit I've no idea how many gph.
Although not much help, I would question it's underlying power compared to a two stroke and given a choice, I would have gone for a bigger engine. It was the biggest 4 st. merc. did at the time, and was very cheap. (Whopping great discount from Valiant who are owned by the same corporation that owns merc/mariner/Johnson/Sea ray/Bayliner/Quicksilver etc etc etc.

[DJL]

Originally posted by John Hughes
My 115 efi Mercury (my first outboard) on a 6 metre Valiant won't pull more than 4750 rpm, and I am dissapointed with top speed, about 35 mph with light load and calm sea.
Am satisfied prop etc correct, and have been told it (engine) adjusts itself according to load!! It's very quiet, reliable, and doesn't seem to use much fuel, albeit I've no idea how many gph.
Although not much help, I would question it's underlying power compared to a two stroke and given a choice, I would have gone for a bigger engine. .

John, I would seriously suggest getting a new prop, with a different pitch. If you are sure its only pulling 4750rpm then somthing is very wrong. The engine will only produce 115HP at max RPM (about 5750).

Contact Steel Developments, they will be able to give you advice.

[Pete7]

Keith posted a reply to the "water proof hatches" post which I have been reading along with some of the other articles and guess what there is one on rib cruising with a 25 ft rib and twin Yam 4 115 hp strokes. This can't be far off what your after.

http://www3.ns.sympatico.ca/leeh/default.htm

If the link doesn't work then its issue 10 and 11 your after.

There is another article about a side by side test of a four stroke, HPDI nad a stern drive which would warrnat reading too.

Keith, good link,

Pete

[zod550]

re the yamaha 4 sk 150. this motor will be out in canada this fall as per my local dealer (british columbia Canada) . It has been tested up the coast at a fishing lodge and all went well with it. I heard Yamaha may be coming out with a 130 4 stroke soon. I have the Yamaha F100 on a Zodiac pro 550 and while the motor is great the boat is underpowered. Like the previous fellow said it was the largert 4 stroke at the time except for the Honda which is way too heavy.