Chainsaw fuel

[hair bear]

I'm looking for thoughts regarding E10 for small engines.
So, with the current storm rattling around outside I thought it a good time to spin the genny over and drag out the chainsaw and get it usable. It's not been run for the best part of two years but third pull and it was away. I don't know how old the fuel in it is but it wasn't 'new' the last time around. It still smells ok and is obviously still viable.
I'm a bit of a survivalist type pack-rat and like to have things like the generator, saw, waterpump etc. fully fuelled with a couple of gallons in cans ready to go but having heard about the horrors of E10 fuel gumming things up and not storing well for long periods I'm wondering what sort of hints, tricks or additives any one can recommend to keep this new fuel from deteriorating. I've seen it suggested on some US forums that 100LL avgas is the way to go but how and where it could be acquired I wouldn't be too sure about.
For the record, the genny is a 4 stroke Honda, and the saw and pump are 25:1 2stroke.
Thanks.

[gecko.cx]

Short answer - don't do it.

Alcohol plays merry hell with all but the most exotic rubbers.
Apart from the fuel line, to allow them to work in any positions, chainsaw cabies are of the diaphragm type which is a rubberised fabric.
Many saws (and other small engines) use plastic tanks. Unless the manufacturer has approved ethanol fuels, I'd be avoiding the stuff if at all possible.

As for Avgas, some race/rally shops stock it and obviously airfields - getting airside to buy it can be a hassle though.

[Matchless?58]

E10 fuel absolute rubbish . Just as an experiment I tried a tank full in my old royal Enfield which believe me runs on virtually any old crap . It doesn't like it at all and has gone from a second kick starter to a none starter ! I had to change the plug drain the tank completely and refuell with fresh fuel to get reliable starting again . One of our club members recommended Esso petrol as being one of the last places to sell non or low ethanol fuel . I got a can of that it's worked so that's where I will be filling up in future . Any petrol with ethanol does not store well in my experience it seems to leave a brown gummy substance around the jets which soon blocks them . I'm not sure how it gets on with fuel injection ? Anyway I would not bother to store fuel now just not worth the agro .

[MrF]

It depends on the age of the equipment, most newish stuff will have ethanol safe o rings and fuel pipe etc and wont blink a eye. Newer fuel injection systems same. I leave the petrol in things over winter and have no issues, but I add stabil fuel treatment to them and its stopped the mess in spring for the 4-5 years Ive been doing it.
Older stuff, yeah, the rubber isnt compatible, its possible to change things to fix this, I'm doing my 101 landrover so it can run on E85 because its 1/5th the price...

[Slooby]

Little late to the party on this, but:

The easy solution is to run a super-unleaded for now as they are generally all still E5

The problem with storing fuels with ethanol for a while is that the greater the ethanol in them the more water they absorb, so you need to add a fuel stabiliser, or drier. Most motorbike specialists and decent garden implement suppliers sell stabiliser/drier additives

As has been said the fuels with added ethanol in place of hydrocarbon fuel stock attack rubbers, plastics and resins (not good for 'bikes fitted with grp tanks - 90's era Hinckley built Triumphs for example) there aren't any fuel additives to stop this, the only option is to replace anything that can be attacked by ethanol with a proofed alternative (there are grp tank coating treatments out there too).

The upside of greater ethanol in petrol is higher Octane ratings and a greater cooling effect on the burn, which is particularly useful on high performance engines, especially turbocharged ones. E85 (assuming it is true E85 and therefore greater than 83% ethanol) is 105 Ron and with the fueling and ignition optimised for it a 20% increase in power over a 99 Ron E5 fuel is up for grabs! The main problem is that the fueling and ignition for an E5 will be different to that necessary for E10 and so on as more ethanol is substituted for the hydrocarbon fuel. The only way this can be dealt with automatically is with a fuel injected engine running engine management that can talk to a 'flex-fuel' sensor that actively analyses your fuel and then tells the ecu what it needs to know about tge fuel in the lines and to adjust parameters accordingly. Not something anything we're generally tinkering with on here then, and so it's back to manually adjusting the advance and retard along with mixture settings and jets to suit tge fuel now in your tank

[hair bear]

My '86 quad bike still has fuel in it from at least six years ago, likewise the '88 genny, both still start on the button, both Honda. I guess once they run out I'll be doing a lot of fuel draining in future. On the up side, once I've finished carving stuff about with the saw, I just empty the tank out to start the bonfire.
Just perusing the manual for this saw and not noticed this before - 'AVOID GASOHOL'. What the hell is gasohol???

[Slooby]

Gasohol is an older Americanism for a Gasoline/Alcohol blend containing 10% or more Ethanol...so E10 then

It was very popular in South America after the fuel crises of the 70's

[gecko.cx]

One problem with ethanol as a replacement fuel for petrol is that is only has about half the calorific value of petrol.
Without modification, a carby engine will run progressively leaner as the ethanol percentage is increased. Boring out the carby jets is the usual mod unless you have a variable jet carby like an SU.
Any engine with an O[sub]2[/sub] sensor should be able to retune it's self, but 'standard' injectors are unlikely to be able flow enough fuel to get full power (double the flow rate is a bit of an ask).

The other follow on is the fuel consumption - if you need twice the quantity of fuel to produce the same power, your tank will only last half as long.

https://www.engineeringtoolbox.com/fuel ... d_169.html

[hair bear]

Ok, so super unleaded it is then, for now anyway.
Had a look at the link, wow that's a lot of numbers! Interesting reading though.