Finished with outboard, pull killcord or disconnect fuel line.,

Concerto said:
If you are leaving an outboard for a number of months before using again, I would recommend stop using E5, shortly to be E10, petrol and change to Aspen synthetic petrol. E5 has a shelf life of about 3 months, whereas Aspen has a shelf life of over 3 years. Yes it is more expensive, but is more reliable. It is used a lot in garden machinery and chain saws due to their irregular usage. I bought 10 litres recently and it cost £20, but considering how little I use I know it can still be used next year or the year after - so makes it far better value for money in the long term.
Aspen 2 | Aspen 4 | Premixed Petrol | Aspen Fuel
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10 litres for £20 is cheap nowadays:)
 
I posted earlier that an engine stops when fuel shut off due to insufficient fuel in the fuel / air mix as bowl content reduces ... so bowl is never fully dry ... for some reason the post does not show.

Ok lets explode some myths :

Straight gasoline leaves no residue : Wrong. It suffers from light, heat and Oxygen - causing GUM deposits. Its why Gasoline has to be tested for Oxystab and treated with Oxystab additives.

Gasoline has different agents added as 'cleaners' - but these are time limited due to vaporisation etc.

Ethanol interferes with 2T blending with the gasoline - there is no evidence at all for this.

Fuel has shelf life and should be discarded : There are a few reasons why gasoline may be a problem to use - particularly starting an engine ..... storage in unsuitable manner which allows light / oxygen and vaporisation ...

Use a decent sealed dark container in a cool corner of garage - and that gasoline will go years ...
 
Refueler said:
Use a decent sealed dark container in a cool corner of garage - and that gasoline will go years ...
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I 'd add that the containers should be full, Not necessarily brim full but with the minimum of air space to avoid the effects of oxygen.

Containers for storage should be metal, not plastic cans or fuel tanks.

My concerns with E10 are two fold:.
Compatibility with hoses and diaphragms in older engines.​
Absorption of water, due to the hygroscopic nature of ethanol, leading, eventually, to a corrosive ethanol/ water mixture settling out.​
​
My plan is to use E5 or, when I can get to a Power Service Station in Sussex, E0 for older engines and low mileage cars.

Worth noting perhaps that Esso say their E5 Synergy Supreme+ 99 is actually alcohol free except in Devon, Cornwall, North Wales, North England and Scotland
​
​
 
William_H said:
The concept of running a carb dry was correct for 2 stroke o/b where the petrol could evaporate leaving the oil in the bowl. With a 4stroke you have only petrol which if it evaporates will not leave much residue. Given that for so many years we ran cars with carburetor bowl and never tried to run it dry before parking I wonder why a 4t o/b is any different. ol'will
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It's to do with the amount of water in the petrol. Left for too long the carb rusts.

Ink
 
Humm I have a yam 4 hp.. Cir 1999? I find it rather heavy on my own lifting it on and off. I inherited it about 15 yrs ago.. But I will put up with it till its knackered then get myself a lighter o/b. It has been fully submerged twice In Salt water up to 20 mins.. I pickled it each time.. I don't service it hardly. I don't run it dry.. It starts on second pull nearly every time even after 3 months off for winter break.. I use it a lot for shopping and and exploring in when anchored up... Stick any old fuel I can get from where ever (petrol of course). Can get on the plane in 2.6m air deck tender.. Wish it would hurry up and die so I can buy lighter ???..
 
rib said:
Oh and I add engine oil in the petrol 100/1 ish too
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Many OB'd brands changed to 100:1 in answer to the Green Brigade ... but it was soon evident that 100:1 was not a good idea and those same brands reverted to 50:1. Few years on and the Greens won ... 4str became the rule for new OB'ds .... making the 2str a 'prized' possession.
 
With regard to Aspen, I do use pre-mixed Aspen in my 2-stroke chain saw and strimmer, but not in my 2-stroke outboard. This is following an unfortunate incident when I used Aspen pre-mixed 2-stroke fuel in my old Mercury 3.3 and it snapped the piston ring within a couple of minutes running. Possibly - even probably - coincidence but nonetheless I did some cursing and suspect that the oil is has properties raster different from normal outboard 2-stroke oil.

Aspen 4-stroke fuel mixed 50:1 with proper outboard 2-stroke oil is fine however, and given how little fuel I use in a year quite a good choice for me.
 
Refueler said:
Many OB'd brands changed to 100:1 in answer to the Green Brigade ... but it was soon evident that 100:1 was not a good idea and those same brands reverted to 50:1. Few years on and the Greens won ... 4str became the rule for new OB'ds .... making the 2str a 'prized' possession.
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Very true - when talking to a leading Yamaha dealers mechanic recently he recommended 50:1 even though the handbook stated 100:1. As most 2 strokes are now quite aged it makes even more sense to give them that little extra lubrication, in my view
 
jdc said:
With regard to Aspen, I do use pre-mixed Aspen in my 2-stroke chain saw and strimmer, but not in my 2-stroke outboard. This is following an unfortunate incident when I used Aspen pre-mixed 2-stroke fuel in my old Mercury 3.3 and it snapped the piston ring within a couple of minutes running. Possibly - even probably - coincidence but nonetheless I did some cursing and suspect that the oil is has properties raster different from normal outboard 2-stroke oil.

Aspen 4-stroke fuel mixed 50:1 with proper outboard 2-stroke oil is fine however, and given how little fuel I use in a year quite a good choice for me.
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OUCH !! But I doubt the Aspen mix was to blame ... BUT being a 'garden tool' mix - the 2T would have been for Air Cooled use .... which means it would resist the running temperature of your OBd more... but not advised 'environmentally' ...
 
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William_H said:
The concept of running a carb dry was correct for 2 stroke o/b where the petrol could evaporate leaving the oil in the bowl. With a 4stroke you have only petrol which if it evaporates will not leave much residue. Given that for so many years we ran cars with carburetor bowl and never tried to run it dry before parking I wonder why a 4t o/b is any different. ol'will
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William - agreed why run them dry? In fact there is every reason not to run a 4 stroke dry.
I have a 2.5 Suzuki 4 stroke, new in 2009. In the first few months of using it in Greece I religiously ran it dry every time I stopped it. Every 3 weeks I had to go back and get the tiny slow running jet cleaned. After the 3rd time the Greek engineer asked if I was running it dry, which I confirmed.
His answer was that doing this draws up and dries out the Gum in the fuel which coats the very narrow slow running jet, and hence the eternal slow running problem.

I never ever ran the outboard dry again - and if handling the outboard the engineer said just drain the carb using the screw designed to drain it.

Since them the outboard has run perfectly - infact all I ever do to the carb is drain out the fuel when left and inspect once a year for crap in the bowl.

So stop running them dry!!!
 
coveman said:
Very true - when talking to a leading Yamaha dealers mechanic recently he recommended 50:1 even though the handbook stated 100:1. As most 2 strokes are now quite aged it makes even more sense to give them that little extra lubrication, in my view
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I did read somewhere that a new engine is more likely to need a higher level of lubrication, whereas an older one will have accumulated some wear on moving parts and will require less.
 
Chris_Robb said:
William - agreed why run them dry? In fact there is every reason not to run a 4 stroke dry.
I have a 2.5 Suzuki 4 stroke, new in 2009. In the first few months of using it in Greece I religiously ran it dry every time I stopped it. Every 3 weeks I had to go back and get the tiny slow running jet cleaned. After the 3rd time the Greek engineer asked if I was running it dry, which I confirmed.
His answer was that doing this draws up and dries out the Gum in the fuel which coats the very narrow slow running jet, and hence the eternal slow running problem.

I never ever ran the outboard dry again - and if handling the outboard the engineer said just drain the carb using the screw designed to drain it.

Since them the outboard has run perfectly - infact all I ever do to the carb is drain out the fuel when left and inspect once a year for crap in the bowl.

So stop running them dry!!!
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Do you mount and unmount the engine ? Or is it on mount all time ?

I would suggest that a 4str is less likely to bad starting if stopped by button / killcord - because its a non 2T fuel mix. A 2str on the other hand will suffer evaporation of gasoline light ends ... running dry (at least till engine stops) allows you to pump in fresh fuel to carb before starting.

As to blocking the idle jet - that's why I ask about mount / unmount ... as I cannot see why Gum should be drawn up .. why would Gum be there anyway if engine is run frequently ??? Gum is a deposit due to oxidation and heat ... it actually takes a reasonably large volume to produce a small amount. A litre bottle would have a couple of very small blobs if pushed to drop out ...

You can do the experiment yourself in fact ........ Glass clear bottle ... half full ... leave it a bright sunny location top off .... wait days !! Literally all Gasoline has Anti-Ox / Gum agents added.
 
Spirit (of Glenans) said:
I did read somewhere that a new engine is more likely to need a higher level of lubrication, whereas an older one will have accumulated some wear on moving parts and will require less.
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As I understand it, yes, a new engine will require greater lubrication until it is "run in". Indeed, that is the recommendation in the handbook ,but after running the engine in, it was then thought that 100:1 would be ok. As refueler mentions there may have been other reasons for this recommendation such as being seen to be "greener"??
 
VicS said:
I don't think you will find anything smaller than 8hp with electric starting
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I have vague memories of 3rd party conversions for some small OB'ds ... (and was going to say possibly late large model Seagull .. but that was actually recoil starter).

My 4.5 Johnson Twin has electric out and I have suspicion that had possibility of add-on starter.
 
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