Yamaha 3.5 - should water come out of the two holes?

[VictorII]

I have a Yam 3.5 two stroke outboard - see picture. http://dyanemaniac.web-log.nl/.shared/image.html?/photos/uncategorized/perenkist2bbm.JPG
It has a water cooled exhaust and this works, since water and smoke come out from the bottom tube near the prop. But it also has two small holes in the leg, about half way down, and only hot air (smoke?) comes from those.

Should the holes spout water? What could be going wrong? I've searched quite long for this but haven't found an answer on the forums, even though the engine gets mentioned regularly - I think as the Mariner 3.5.

 

[VicS]

Id expect some water to come from those holes with the exhaust gases but it may be no more than a few droplets or a mist. Hold your hand there and see if it gets wet.

Provided the engine is cooling you have no problems.

If not done recently or if you do not know the history it would be worth changing the pump impeller at some point.
Also check the gear oil for signs of water ingress

You dont give the year or any of the model details so cannot look anything up and i do not know if the model has a telltale.

But there were some air cooled Yamahas IIRC !

if recent you may be able to find an online owners manual at http://www.yamaha-motor.com/outboard/service/servicehome/home.aspx and if no older than 1984 parts list and diagrams (The site is really for engines imported to the USA though)

If it truly is the same as the mariner 3.5 you may have more luck with http://www.brunswickmarineemea.com/download/preparesearch?mod=4&lang=EN for an owners manual BUt the site may only cover American made models
likewise http://www.crowleymarine.com/index.cfm for parts lists and diagrams

 

[DownWest]

Vic, I think this is aircooled, looks just like my '80 3.5 hp. If so the answer is no to water coming out of the holes. The cooling water for the exaust is blown up the leg by a forward facing pipe behind the prop.
A

Edit to add. A gassy damp output would be in line. Prob they are there to avoid backpressure.

 

[Joe]

Outboard

It is indeed air cooled
It uses a really basic system using the exhaust gasses to try and pull up some water to help cool the exhaust but its very hit and miss especially on old ones ( which they all are now )
Dont worry about it
as long as it runs ok and dont overheat it will be fine.
Make sure the special spark plug cap is still fitted tho as a lot get removed.
It covers the entire hole in the cowling where the spark plug goes in to send the wind round the engine fins and out the bottom

Joe

 

[VicS]

If it is an air cooled engine then it'll be pretty obvious from the fan, cowling and cooling fins. I have an old 5hp Volvo Penta that's like that.
That has a scoop behind the prop to catch water for cooling the exhaust. I really don't remember if much or indeed any water comes out of the exhaust pressure relief ports.

Probably no water pump impeller to worry about then.

 

[Keith 66]

Dont worry about it, the cylinder barrel & head is air cooled by ducted fan that vents out underneath, the exhaust is water cooled by the simple & efficient expedient of a pipe that hangs down just behind the prop, when its in gear the propwash blasts up the pipe & cools the exhaust, there is no impeller to go wrong. Best bullet proof outboard ever made though you might need ear defenders cos they are a bit noisy!