Loads of 2 stroke oil in the test tank.

[Danceswithseagulls]

1st of all, Hi to every one, my names Steve and I've just joined your forum. When I was a young boy I used to have an 18ft clinker built boat with a 40+ motor. I've worked at sea as a Master on pleasure craft and a couple of small trawlers for many years and now have time on my hands, and so I'm now the proud owner of a 1965 40 plus. It is now running like a clock but my problem is the excessive 2 stroke oil it coughs out the exhaust. I'm sure that I'm correct that the mix for this motor is
10-1 for a motor of this age, that's 100ml of oil to 1lt petrol? So why so much oil waist in the test tank? And dare I use less oil? If so is there any thing I need to do to the carb? I live in Tenby which has a small harbour and a harbour master with the eyes of a Seagull, excuse the pun but if this motor discharges that much oil in the harbour he won't be happy! Any advice would be most appreciated.

[Oyster 49]

Welcome! There are a few things you can do. Firstly your seagull will run fine on a weaker mix of oil, perhaps up to 16:1 petrol to oil. If you are running that mix you will then have the engine running rich as there is more fuel in the mix. You can adjust this a little by screwing the carb needle in the slide down to weaken the mixture. Do this a turn at a time and don't make the mixture too weak. I find the mixture is about right when the engine runs at half throttle smoothly with very little "Chugging" as it runs.

The seagul is a total loss oil system so some oil must always go through the engine and down the exhaust. If it didnt it would seize up very quickly!

Also there are some good biodegradeable two stroke oils about which you can show to anybody moaning, and ask if they are using biodegradeable diesel in that boat of theirs that coughs out oily crap when it is cold! The FAQs on the main SOS site tell you how to adjust the mixture.

Once the engine is running, check the plug occasionally to ensure the mixture is OK. The plug should not be too white.

Don't forget to flush in fresh water regularly, to keep the waterways clear.

[Danceswithseagulls]

Thanks for the speedy reply, I was hoping there would be somthing I could do, I was a bit worried about using less oil incase it wrecked a motor that's survived for 48yrs. I will give it a go tomorrow.. Can't wait to get it on the back of the boat..
Thanks again.

[charlesp]

Please don't worry about wrecking the motor, it'll be fine. The major issue with changing the oil/petrol mix is one of running too rich or too lean. The bearings and rings etc will take it.