Outboard Oil Mixing for Dummies

January 24, 2014 at 11:26 am

While the 8hp 2 stroke 35kg monster languishes on its side in the garage awaiting a decision on its fate, I have been looking at how I might improve its running if I do decide to keep it.

I’ve come to the conclusion that its unreliability and smokiness may well be down to simple operator error with the mixing of the oil and petrol that goes in the damn thing  –  I can never remember how much I’m supposed to use and every time have to refer to the manual, or the internet …and then the measures on the side of the oil bottle aren’t that easy to use so I generally add a bit extra for “‘luck” (and although I have heard that in life you can never be too rich or too lean, it appears that in the clattery world of outboards they are mutually exclusive and it is actually better to be too rich than too lean…)

Running too rich (ie using too much oil to fuel) causes the outboard to be smoky, and the spark plugs to blacken (they should be the colour of rich tea biscuits apparently) and the engine can run rough.  Conversely running too lean (ie not enough oil to fuel) can damage your engine.  (I found a great 2 stroke trouble shooting guide here.)

What I need is a proper measuring jug for this purpose.   Then I thought that I couldn’t possibly be the only person to have ever had this issue and google would no doubt provide the answer… Which is how I came to find  the small plastic jug on eBay like this – 2 Stroke Outboard Engine Oil Measuring Jug for £6.49 (FREE Standard Delivery)

I thought this was a bit steep for a plastic measuring jug and yet another example of a ‘marine’ inflation… So on my next trip to Lathams I found a small 500ml plastic measuring jug in the kitchen section for the princely sum of 39p.  With the addition of a sticky label and a sellotape covering to provide some protection against the inevitable oil drip and I have this:

2 or 4 Stroke Outboard Engine Oil Measuring  Jug

Probably keep this single purpose, rather than use it for scrambled eggs as well…

So, for the record (and repetition helps memory) my 2 Stroke Mercury Saildrive outboard  needs a 50:1 mix and the green petrol can I usually use is 5 litres so I will need 100ml of 2 Stroke oil for that can.  (There is a good chart I found on the internet here)

I added the 100:1 details ‘just in case’ I do end up with a brand new outboard as I will probably need to use a 100:1 mix to run it in.

As for the one in the garage, I’ve been quoted £90 for its annual service at Norfolk Marine in Wroxham, and am watching the ‘going prices’ for outboards on eBay… and I’ve sought council from the Hurley Owners Yahoo Group and been recommended a nice new 6hp 4 Stroke Tohatsu is what I need, weights 25kg and will fit in the outboard well – more on this soon no doubt.