Yamaha 3.5 AC

[gybemark]

This week end I bought a small boat with a Yamaha 3.5 AC outboard. It is my first outboard.<br /><br />It is clearly <br />1. elderly<br />2. Air Cooled (AC)<br />3. 2 Stroke<br /><br />My first question is what fuel (unleaded or lead replacement) and fuel mix (petrol/oil ratio) can anyone guess I should use?<br /><br />Secondly, does 3.5 mean horse power, and if so, is that capable of moving a 200 lb/14 foot boat with 4 adults on board against a normal UK estury tide (say 2.5 knots of tide)?<br /><br />Thirdly, is there any amaintenance or is it really as simple as it seems, just the air filter?<br /><br />Thanks in antcipation.

 

[steelespike]

Re: Yamaha 3.5 AC

First it should run fine on unleaded fuel.Lead has no effect on 2 cycle motors.<br /> The mix is 50:1 My service manual says Outboard 2 cycle oil.Some believe it should be aircooled<br />2 cycle oil.??<br />The powerhead is air cooled but im pretty sure the exhaust leg is cooled by water scooped up behind the prop try to be sure there is water comming out of the holes (if any) in the exhaust leg.It may over heat if the leg is not cooled properly.<br /> It is indeed a 3.5 hp.<br /> At 4 people you will be at the max.<br />weight for your boat Unless it is a big 14.<br /> There may be a plate on the transom giving the capacity. If not give us the demensions, Actual length,beam,depth,transom width and if aluminum or fiberglass. we can get an idea of the rating.<br />I think I would try a run with one or two aboard<br /> See how it handles the tide flow.My guess is it would handle it but the over the bottom speed would be REALLY SLOW.(It will be slow regardless of the tide.)<br /> And I sure wouldnt go too far from land fall.<br /> Be careful.

 

[gybemark]

Re: Yamaha 3.5 AC

Thanks for your response to date - most helpful.<br /><br />It does indeed look like the exhaust is water cooled, as there are some holes one third down the leg, and a large hole where the exhaust come out.<br /><br />Some other info if any use<br />Serial Number 642 S 20048<br />Prop is approx 7.5 inch diameter aluminium<br /><br />No plate on the boat, except the makers. The boat is 14 foot Skipper ex-sailing dinghy,<br />fibreglass, twin skinned, with bouancy tanks, so it shouldn't sink even when capsized.<br /><br />Beam is 5 foot.<br />Height at bow is 2 foot 6 inches (keel level to deck lne)<br />2 foot at midships<br />and 1 foot 3 inches at transom<br /><br />We will be using it inshore tidal creeks and esturies, never more than quarter mile from land, and no big waves.