running motor dry of fuel after use

[bugsytwoshoes]

Two questions ----I have a new 60hp Yam. 4st. tiller steer, would I be better off running the motor out of fuel when flushing or not. I can dissconect the fuel line easily as it has a portable tank not underfloor. I do not use the boat a lot maybe every six weeks and I worry about stale fuel left in the motor. Second question does standard fuel ( 91 octane ) contain ethanol I have been told that it does contain ethanol and we are not told about it. ???????

[Triple]

How long is it sitting between runs? Unless it more than a few months then it will be fine, if in doubt use products like stabil or fuel doctor. Premixed carby two strokes may have issues with fuel evaporating from the bowl and leaving the oil residue turning into a varnish like substance lining the bowl and when fuel is added can stir it up and block jets etc (and some say if run dry then drying out gaskets and orings causing them to shrink)
Is it efi? if so then you should not run it dry as you could damage the fuel pump (fuel lubes and cools the pump) and possibly injectors due to dry running damaging the injector valve.

Long term storage is a different ball game to just a few months between outings..

All unleaded must be labelled at the pump if it contains ethanol or not.. have a good look around the pump labels (some bp's currently have ethanol supply issues and their regular (91) does not contain ethanol (label removed or crossed out).

Do NOT use ethanol fuel.

[stue2]

well from what I have read there is no guarantee that ethanol is not in low octane fuels. There is no guarantee that what I have read is accurate either but they did suggest that ethanol has been found in low quantities in low octane fuels that are labelled ethanol free. I have been using Premium for a few years now and not had any issues at all.

You better read the manual on storing your motor. I have a feeling that running it out of fuel will also run it out of lubrication.

Cheers, Stu

[Dan5]

I had the same engine........don't bother running it out just disconect the fuel line thats it.......efi sealed system..........in fact they are a bugger to start after running out of juice.

Dan

[oldboot]

Firsly as has been said it is unwise to run a fuel injected motor out of fuel, for a variety of reasons.

The fuel in the injection system wont go off as fast as it would in a carby, which is vented to air..but modern inleaded fuel does go off, and is expected to be below spec within 60 days.

The best bet....if you cant take the boat out, at least give it a run on the muffs or in a tub at least once a month. on fresh fuel.

Then before the fuel goes stale run it thru something else.....I recon the best option is to empty the tank after you finish flushing if you don't intend to go out real soon.
That way you have fresh fuel you don't need to waste.

Now there have been a coupl of either, myths or misunderstandings about fuel.

In Australia, the fuel companies CAN NOT put any ANY ethanol in fuel without it being labled on the pump.
The hokus pokus about there being a bit of undeclared ethanol in this or that fuel, is comming from the states......I doubt that it is true there either.

As for two stroke going off faster......yes it does... but my understanding is that the varnish comes from the decomposing fuel and not from the oil.....the oil simply accelerates the process.

cheers

[stue2]

Whats your views on containers Oldboot. Do you think sunlight can speed deteriation up as in steel v plastic containers. My view is that it does. We use the fuel in the red containers first before we open the steel ones.

cheers, Stu

[bugsytwoshoes]

Thanks for the answers guys you can trust Ausfishers to solve any problem ( well most problems. )

[fisho8]

My old man always used to start and run his engine every 2 weeks between trips and just let it run for about 5 minutes that is what I do with mine also a few other people I know do the same thing.

[oldboot]

I think its 6 of one half a dosen of the other with containers.
The manufacturers specify that fuel should be stored in cool dry places.

There would be very little UV gets thu the thick opaque plastic containers we use....the UV would be more of a problem to the plastic than the fuel.

BUT the temperature..ahhh well there seems to be no question that high tempeatures accelerate degradation.

As far as the fuel life...I wont take my boat out on fuel that is more than 30 days old.

cheers



if the metal container gets hotter well that one would degrade faster.

[stue2]

Now there have been a coupl of either, myths or misunderstandings about fuel.

In Australia, the fuel companies CAN NOT put any ANY ethanol in fuel without it being labled on the pump.
The hokus pokus about there being a bit of undeclared ethanol in this or that fuel, is comming from the states......I doubt that it is true there either.

cheers

Sorry to be a pain Oldboot but labelling laws say that if the fuel contains more than 1% ethanol it must be labelled. Ethanol is used to boost the octane levels in some high octane fuels. Which suggests to me that there is no garentee that fuels don't contain ethanol even at low levels.

This also means the premium fuel I use could possibly contain ethanol but it does seem to store better than regular fuels

Cheers, Stu

[stue2]

I think its 6 of one half a dosen of the other with containers.
The manufacturers specify that fuel should be stored in cool dry places.

There would be very little UV gets thu the thick opaque plastic containers we use....the UV would be more of a problem to the plastic than the fuel.

BUT the temperature..ahhh well there seems to be no question that high tempeatures accelerate degradation.

As far as the fuel life...I wont take my boat out on fuel that is more than 30 days old.

cheers



if the metal container gets hotter well that one would degrade faster.

Ok so the heat thing makes a lot of sense. Plastic components in my industry are known to contain the heat whereas steel will disperse it. The steel container is cooler than the plastic but my boat prefers plastic. just have to use it sooner.

cheers, Stu

[oldboot]

I doubt that 1% of ethanol will do much either way, I doubt that it would effect the moisture holding capacity of the fuel and 1% won't de doing much for the octain either....serioulsy not worth worrying about..besides there is not a thing you can do about it anyway.

It is the 10% ethanol we have to worry about and that is a real and clear issue.

As for the temperature....I doubt that you could make a simple choice between plastic or metal even on the basis of temperature.
Most metal cans are either polished metal or painted dark colours, both are good absorbers of heat and better conductors than plastic.

I do not believe it is possible to make an inteligent choice between metal and plastic from the point of view of fuel shelf life.

One thing for sure though..plastic does not corrode, and that IS a real and dominant issue in boats.

cheers

[NTMID8]

It probably doesnt help you much but my mechanic has told me with my engine (60hp 2strk) to always run it empty on the muffs coz the oil in the fuel will build up in the carby if left.

[oldboot]

Thats not unreasonable in a carby two stroke, particularly premix.

BUT the main issue is the fuel will remain in the carby and the more volatile elements will evaporate, and the less volotile eliment will oxidise, polermerise and turn into varnish.

The oil realy don't matter much.......if you have a postmix two storke and the fuel runs out the oil will keep pumping and you will get more oil in the carby...depends on who you speak to wether this is a good or bad thing.

cheers

[stue2]

Maybe I'm looking at this the wrong way.

1% of 25 ltr is 250ml or 1% of 200 ltr is 2 ltr.

NTMID8 correct me here but do etecs winterise with an extra oil process?

[oldboot]

Um yeh your maths is correct, and your point is??

[stue2]

Oops, sorry. in a hurry.
point is the gunk can still build in the tank. If you dont clean it out properly and not everyone does in the off chance they will get out in a month or so.

A tiny little pocket of brown sludge is all it takes

I just picked an old honda 6hp motor for a small auger up and it still have the old leaded petrol in it. started in three pulls. And the tank is spotless