I am sure if that comma oil(which is prob made in the same factory as duckhams/castrol) is ok to use in a high performance motorbike it will be in your old tech mariner.
Really? I thought 2 stroke outboards and 2 stroke bikes ran at different temperatures therefore bike oils are not suitable for use in an outboard which run cooler. Could be an interesting if not expensive way of discovering if this is true.
Rumour has it that the Mariner/Merc 50 & 60 was designed by Yamaha and first appeared in this country about 1991 time. The design incorporated lost foam casting techniques to reduce the number of components and complexity of the power head. Why is this an "old tech mariner" engine? mine was an excellent little engine that never gave any problems.
Oil is only as good as its additives and the specification is controlled by the American Petroleum Institute, provide both oils meet the same API standard there is no problem but , Pete7 is right there is a strong likelihood that an oil formulated for a bike will differ in its additives to an oil designed for an outboard.
Oil is really so cheap compared to getting it wrong I wouldn’t mess around just get the right stuff.
Des
Really? I thought 2 stroke outboards and 2 stroke bikes ran at different temperatures therefore bike oils are not suitable for use in an outboard which run cooler. Could be an interesting if not expensive way of discovering if this is true.
Rumour has it that the Mariner/Merc 50 & 60 was designed by Yamaha and first appeared in this country about 1991 time. The design incorporated lost foam casting techniques to reduce the number of components and complexity of the power head. Why is this an "old tech mariner" engine? mine was an excellent little engine that never gave any problems.
Pete
Yes they DO run at different temps hence the comment about corrosion inhibitors - a bike engine runs hot enough to burn most stuff away but a boat engine doesn't hence the need to do something about the corrosion - in a race engine it will be inspected/stripped/cleaned etc so not an issue. You could also use a anticorrosion additive to save wasting the oil.
When I said "old tech" I wasn't being derogatory - just that they aren't like the optimax/ficht etc which needs higher spec oil.
As to "lost foam casting technology" don't think it is that special - been around for a long time and is virtually the same as "lost wax" casting which was first used about 5000bc!!! Still used today for turbine blades - nothing much new in the world after all.....
I bought the Comma out of ignorance thinking that any 2 stroke oil will do.
However,the high revving hot air cooled verses medium revving water cooled debate has spooked me and I want err on the side of safety.I have to respect the opinion of more experienced people than me on this one.25 litres cost me £45 and I can just bring it back and get a credit note.It would take a lot of petrol to burn that lot off and I don't want to spend hundreds if I trash the engine
I reckon having read some of this, I will always stick to TC-W3 graded oil. To be sure, one can check at www.nmma.org to see what oils have this standard. Can't upload a word document. Just all about outboard oils. Most recommend "Only use TC-W3 grade oils" All to do with the low oerating temps, rpm, low ash etc.
Absolutely, as Des said the amount of oil someone is going to use each year for a leasure activities is cheap compared to the cost and agro of an engine rebuild.
but , Pete7 is right there is a strong likelihood that an oil formulated for a bike will differ in its additives to an oil designed for an outboard. 
I wouldn’t mess around just get the right stuff. 
