can someone let me know if they have had a 2 stroke and a 4 stroke on their yacht and if the noise is mucg different,
depends on the motors but all the modern 8 to 10 hp are fairly quiet, unless you are worried about an extra few kilos or the extra cost to buy new the 4 strokes are way better, more economical, quieter and happy to run all day at low revs. No smoke either. Generally the Yamaha 9.9 hi thrust 4 stroke has been the most popular yacht outboard motor and proven over the last 25 years. They also make an 8 hp. They have a large prop and a 3 to 1 reduction gearbox that works well in reverse also. Lots of other good brands though. If you are only pushing a very light or small boat you can get away with a lesser motor, in calm conditions even a 2 hp will push you. My last boat was a 46ft ex race cat and 1 1985 9.9 yamaha would push us at 7 knots , with 2 motors 9 knots.
I also have the 9.9 high thrust. It's great.
Benny if you are chasing one, I know of someone who has one for sale. It is approx 2 year old I believe, and is long shaft version.I think if was around $2k (mine was $4,xxx when I bought it)
PM me if you are interested and I can pass on his details.
I've got a Yamaha 9.9 high thrust and love it. It powers my 30' cat very well and you can speak on the boat at normal conversation levels, even at high revs.
We have got 2 strokes on all of our yachts and they are great. Most outboard motor brackets are not rated to put a 4 stroke on them as they weigh to much. One of our yachts has a Yamaha 8hp 2 stroke and is the best motor, it is very quiet and has great reverse thrust. And the other yacht has a Mercury 5hp 2 stroke and push's an 7.7m yacht with no problems. 4 strokes are alot more expensive to buy and weigh more and cost more to service, 2 strokes for me!!
I have a Tohatsu 8hp 4 stroke. Coming from motorcycles, and many two strokes, the four stroke is easy to service, because it only needs an oil and filter change, along with spark plugs. A four stroke usually has greater longevity and uses a little less fuel. They usually start easier and there is no need to worry about 2 stroke fuel mix issues.
The downside is that it's just too large to put in the well, so it lives on a lifting bracket on the stern, but the good part of that is that it's much quieter out there.
It uses just on a litre per hour at hull speed of 6 knots.
Perhaps you could go to some of the boat hire places near you and see if they have both, then try them for yourself.
Michael
My preference is 2 strokes because of simplicity and weight (or lack of).
I currently have a Yamaha 8hp 2 stroke which is a great engine. Only issue is that I often need to clear the tell tale water outlet with a piece of wire and removeing the lower leg to change the water pump impeller is a little bit tricky with releaseing the gear change rod.
Yamaha always produce top quality products.
Another engine I had was a Mariner 9.9 hp 2 stroke which was also an excellent engine.
A feature of that engine was the gear change incorporated in the twist throttle.
This is a great thing to have especially if your engine is mounted on the stern. Changing from ahead to astern is so much more efficient especially if you are trying to concentrate on a smooth docking. You don't have to look behind and reach back to a gear lever on the side of the engine.
As an outboard mechanic, 4 strokes cost more to service, you have oil, oil filter, sump plug washer, rocker cover gasket and anodes in the block to replace ( if you can get them out ) plus the extra labour charge to replace the above parts and oil disposal..
Dont be fooled by the "myth" that 4 strokes will go forever because in the marine environment, they dont. 4 Stroke outboards have alot of corrosion problems which is why they have anode's in the engine block which are to be replaced every 12 month's
All of our 2 stroke outboards start within 2 pulls and are easier to pull over than a 4 stroke, the only advantage i can see with a 4 stroke is fuel economy, they do get better fuel economy than a standard 2 stroke but thats why i have sails for!!!!!!!!!!!!!!!
All great reply to your question. I wont add to that, to decide witch one.
What is main use, get you from mooring or marina and back. Than 2 stroke is
unbeatable. For me 2 tons and Bass Strait 9.9 Yamaha 4 stroke is a must.
/can't afford to run 30 hours 2 stoke anyway/.
thanks for all your help, i have decided to go with the 4 srtoke. i am sick and tired of mixing the oil in and i always stress out that if i dont use it up it the fuel will bugger up, im not even sure if that can happen. i managed to get a good deal on a tohatsu 9.8. the majority of use will just be for manouvering but also running up through the bay. i will let you know how it goes
hey all, well good news the motor went great, it moves us along really well, and it is nice and quiet.
Select to expand quoteEnsure you use non ethanol unleaded.
second that.
We have a local Apco that ensures none of it's fuel contains ethanol.
Lot's of the fisho's fuel up there.
