Saving Old Seagulls

http://www.youtube.com/watch?v=jDRgOTtHTe0 Here's my 68 40+ I got before Christmas that I did some work to and now it runs great. I didn't have any 10:1 so I ran it on 16:1, but when I run it on a boat, I'll use 10:1.

Does the American two stroke fuel come ready mixed then?

I mix it myself, but I only had 16:1, which I run in my other vintage motors.

So pop down to your local gasolene purveyor with a gallon can and purchase sufficient to top up the 16:1 to achieve 10:1.
I'm much too old to work out the measure required but I know you will able to . . .

I'm much too old to work out the measure required but I know you will able to

Obviously. To change 16:1 into 10:1 you have to add oil not gas

10:1 is 10% oil 16:1 is only 6.25% oil ...... so you need to add 37.5cm³ more oil to a litre


Oh rats the OP is in USA. Even I am not going to work it out in US ounces US pints and US Gallons One day with a bit of luck they will join the rest of the civilised western world and discover litres and cm³

Perhaps I will its another 0.6 ounces of oil per US pint. 4.8 ounces per US gallon

Since its a 1968, 16:1 should be just fine. That way there will be no chance of any mixing foul ups, since your other motors are running 16:1. After all, it could run 25:1 with just the needle change in the carb. If you need to change the setting in the carb to lean or richen the mixture, it is recommended [in the manual, I believe] that you do not exceed 3 turns in from flush [the top of the set screw] with the top surface of the throttle piston that the set screw is postioned in.[Villiers carb.]

1968 and later motors can run as lean a gasoline or petrol mix as 25:1

Kia ora Phil and others who may be able to help,
I have just changed my needle so that I can run my 72,40 on 20:1.
Am having trouble tuning it in the tank and at present smoothest running is about 1and 1/2 turns above flush !
Is that likely to be the case?
Which is rich - screw down or screw up?

Thanks ,

Chris - novice Kiwi

Hi,flush with the top of the the throttle piston is the start point, screw down [clockwise] for leaner,counterclockwise for richer. Many people seem to run them too rich, of course, too rich is better than too lean. Judge by running on boat, wide open for a few minutes after warming up, shut off abruptly, check plug should be clean no fouling and a dark brown, milk chocolate to dark chocolate colour. Try not to loose it over the side, wouldn't hurt to have a spare. At idle and slow speed, just on the lean side of four stroking. Juggle those two and you should be about right. The one that really matters is full throttle setting. If two turns out gives the right results, two turns out it is.

hey seagull guy, try this.........

step 1. pour out 1.7 litres of 16 to 1 mix into whatever you mix it in
step 2. add 400 millilitres of straight gas
step 3. add 100 millilitres of oil

presto! ........... 2.2 litres of 10 to 1 mix!

or simply measure 2.125 litres of 16 to 1 mix and add 75 millilitres of oil for the same result
i'll let you work out the american equivalents. cheers