Over winter we often don't get out on our boats as much as we'd like for various reasons and I've heard a few sad stories about the negative effects of stale fuel on engines.  I imagine this may be a more a common issue than it is common knowledge?By way of example as a basis for starting a discussion, my own circumstances involve a boat with a half-full tank (300l) that hasn't been out for a couple of months - probably typical of a lot of boaties situations - the engine gets turned over in the drive but most of the fuel just sits in the tank for extended periods.I'm wondering if a fuel additive such as Fuel Set (made by Liquid Engineering in NZ) that appear to be designed to prevent or at least mitigate the effects of stale fuel is the answer?

Just use all the fuel or if not pour it into the car when you have finished boating, unless you use the boat more offen, i give it a week 2 tops before i use it on the car...

We use totes, 2 weeks and it's in the cars :) fresh is best  i have free diesel for life but petrol cars and outboards do not run on diesel.. 

My mate in Hamilton uses Gull fuel as he noticed his fuel was going stale with not using it and he got told by boat shop to switch to Gull as doesnt seem to have the problem as is better quality fuel from singapore and now he doesnt have that problem

He used to find that on the fuel from other stations it would be hard to start after a month or 2 (with new engine) but the Gull fuel he doesnt have that problem.

if I can offer one thing guys and that is to top off your tanks pure and simple, leave them half empty or is that half full they condensate, now the last time the boat was out i drained off some for the truck and filled with new stuff, worked a charm.

Have heard Gull fuel has higher octane than Marsden Point varieties even though it's marketed in the same ratings although has higher ethanol content. Be carefull with older motors/fuel systems as it can be hard on o-rings, hoses, primer bulbs etc. Some US marinas wont sell any fuel with ethanol content. Have seen postings on US websites of people driving miles to find old school fuel for their beloved two strokes but I guess it's still dirt cheap compared to what we're stuck with! 

I have often used fairly old fuel, sometimes up tyo a year old and never had a problem.
Maybe I have been lucky.
Never run my motors hard out for any length of time,
never had hard starting
always run a water seperator and check it after a short run if the boat has been sitting for ages.

So apart from water, what exactly are the problems you expect to encounter using old fuel?

I have heard of cars refusing to start on old fuel, but then going as soon as new fuel is put in.

I had an old telstar sitting in my drive for 2 years, put a battery in it, started it up no worries, and took it for a drive, no lack of power, no rough running...

When I had older 2 smokes they ran on old fuel just fine.

Sufishent wrote: There was a thread on this a while ago - http://www.fishing.net.nz/asp_forums/ethanol-blended-fuel_topic52373.html Gull fuel is NOT recommended for use in a marine environment - this from Gull website: http://www.gull.co.nz/assets/Uploads/ETHTIPS.pdf - please note point 4

Correct when like the article says it is for there force 10 & 96 not suitable for outboards --- can ONLY use 91 fuel from Gull in boats....

I've never had any issues with the high octane stuff but certainly had some 91 go off after lots of months.