fuel mix

[BobA]

I wonder if anyone can give me a foolproof way of mixing fuel and oil in a 100 to 1 ratio for my spare Suzuki O/B - i cant seem to get it right and get no end of smoke.
Bob

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[Evadne]

I may have missed something but have you ever tried a small measuring jug? 45cc of oil in 4.5 litres (1 gallon) of petrol is usually close enough.
Alternatively, you could do as I did and buy an electric outboard. Then it's just plug and pray, as with any other bit of electrical kit, but without the bonus of petrol all over the boot carpet on the way home.

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[steve_cronin]

Maybe, if it's the SPARE outboard it is left with fuel in the carb. every so often so that when you start it some of the petrol has evaporated leaving a stronger oil mixture than intended. Apart from nasty smoke and smells this can't do it much harm. Even fuel left in the tank for long periods will evaporate it's petrol constituent to some extent and richen the mixture.

What I use is a 2 litre kitchen measuring jug (plastic) and a medicine measurer (little pot with a pourer) available from pharmacies and marked 10cc 20cc & 30cc. I pour 1 litre of petrol into the measuring jug and then 10cc of oil into the medicine measurer. Tip this into the oil and swill it around. Then into the outboard fuel can or tank and off you go.

Use double the quantities if there is room in the jug to swill it around - even stir it.

Steve Cronin

<hr width=100% size=1>The above is, like any other post here, only a personal opinion

 

[Col]

I have one of those universally available 1gal / 5ltr green plastic petrol cans. Use the cap as fitted and put 2 capfuls in to 5 ltrs, and it works out to 100:1

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[Johnjo]

Thats a really handy tip. saves mucking around
with measuring flasks.

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[Keith]

the problem withoutboards that have been left standing as stated in previous replies is that the petrol evaporates away, but what most people do not realise is that the mixture is set for full throttle to stop it seizing so at partial throttle openings it runs oil rich, when you bring it down to idle you notice it smokes alot more, second problem occurs when you switch it off because the mixture is passed through the crankcase this is where the greatest concentration of oil is and thats why on initial start they smoke so much, side effect of this is you will go through two or three upper main bearings to one bottom bearing because on initial start up the bottom bearing is swimming in oil and the top is starved..........keith

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[LadyInBed]

Absolutely Foolproof

A plastic 35mm film container filled to the brim holds exactly 30 miliLtrs. So mark the film container off into thirds and you have one third (10ml) to one ltr of fuel (or full to 3 ltrs fuel).
I use a one ltr plastic bottle to measure the fuel from the petrol container to the 2 stroke container (marked large with 100:1)

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[Egbod]

I use an additive to stop the fuel from ageing. I think it is a Johnson (OEM?) liquid called 2+4 and it seems to help. Only very small amounts are needed. As for the fuel mix beware of calculating what 1:100 etc is as the 2-stroke oil makers claim to have already added some petrol to help the oil mix with the petrol in your tank- so you need to put in more oil than the calculated amount. I use the instructions on the origial bottle and that bottles graduations. I know that this is not very accurate but my new outboard has interesting instructions. I can use 1:100 but the instruction book recommends that for "professional use" you can use 1:50. I expect professional use to be pretty frequent compared to my occasional use. I mix my fuel to be on the slightly weak side of 1:50 in the hope of providing better protection and getting longer engine life.

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[Egbod]

I use an additive to stop the fuel from ageing. I think it is a Johnson (OEM?) liquid called 2+4 and it seems to help. Only very small amounts are needed. As for the fuel mix beware of calculating what 1:100 etc is as the 2-stroke oil makers claim to have already added some petrol to help the oil mix with the petrol in your tank- so you need to put in more oil than the calculated amount. I use the instructions on the origial bottle and that bottles graduations. I know that this is not very accurate but my new outboard has interesting instructions. I can use 1:100 but the instruction book recommends that for "professional use" you can use 1:50. I expect professional use to be pretty frequent compared to my occasional use. I mix my fuel to be on the slightly weak side of 1:50 in the hope of providing better protection and getting longer engine life.

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[jerryat]

Hi !

Yes, I agree with your latter comments re the richer mix. The suppliers from whom I've bought small 2 stroke outboards, have without exception, strongly advised me to ignore the 100:1 ratio 'recommended' by the manufacturers and use 50:1. They explained that this would definitely increase the life of the motor and that 100:1 was far to lean for effective long term lubrication.

As I sold my Mariner 2hp in full working order after 18 years use and have similar expections for my 'new' (6 year old Yamaha 2b) I think they were right!

The comments from Keith reinforce this view it seems to me and the cost savings of the weaker mix just don't make economic sense IMHO.

Good sailing!

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[Keith]

further to this thread slick 50 do an additive for two strokes, that works quite well ,two guys in the motorcycle club i was in went up to ride the scottish six days trial identical bikes nearly identical age but one was slick 50'd and the other wasn't, to keep the story brief the bike that was treated, came back and ran perfectly for a further nine months the other bike came back and had to be re-bored, bear in mind that these bikes are performance machines and nine mths doesn't sound long but when you consider theabuse a comp bike has to deal with, the outboard that's been treated is going to perform near its peak for a lot longer ..............keith

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[Egbod]

I have another idea. What 2 stroke oil are you using? Marine 2 stroke engines run fairly cool (compared to a motor bike) so need marine 2 stroke oil which burns better at the lower temperature. My outboard use is fairly low so I buy a well known marine brand of 2 stroke oil in the hope of avoiding problems from poor burning. I guess the next question is what brand of petrol are you using? Several items in the daily papers have recommended the use of good brands and NOT supermarket petrol which is "gassed" to "improve" it. Good brands are reputed to burn better, not clog the engine up and give better MPG that balances out the extra cost. I think the recommended petrols were Shell and Texaco.

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[Keith]

I actually use whatever o/b oil i can get hold of, if its got an sae number on it thats fine with me, but i do use the highest octane petrol i can get...keith

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[BrendanS]

Slick 50 got hammered by a few government and class actions in the US, and are no longer allowed to advertise many of the claims they used to make for it. Many feel they are an expensive waste of time, but I'm willing to be convinced by scientific rather than 'a friend says that' claims

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