I remove all fuel every time I leave my outboard for a long period of time It's a nissan 3.5 so I just turn over pour gas out of tank and then start till run out of gas . then mix fresh gas next time I use . I use the left over out board gas for the weed eater
Your weed eater has essentially the same (or smaller version) Walbro type of dipharam impulse carb thats used in chainsaws, etc.
Water contaminated or separated bi-phased fuel easily 'dry out' through the small vents and passages that connect to the 'open to atmosphere' venturi section in such carbs, - the small series of 'idle jet passages', etc. in such carbs.
The Walbro type uses the gasketing of the diaphragm chamber as its check valves (small 'flaps' in the diaphragm gasket) ... and with 'gumming' fuel the 'flaps' are the components that get 'stuck' and 'gummed up' first.
In ALL of these small carbs and especially those with multiple teeny idle ports, its always 'best' to drain (blow out) the carb, then prior to storage for greater than 60-90 days, rinse out the internals with Isopropyl alcohol to prevent gumming up of the small passages and especially the 'flap' type check valves that are integral with the 'gaskets'. ALL small carburetors will benefit from 'blow out' and rinse-out with IPA when storing for long periods.
Anyone can 'separate' ethanol/water from gasoline, easy to do if you have the knowledge of vacuum distillation using all *explosion proof* components ... the gasoline is the first of the fractions to come off, but that vacuum distilled gasoline is mostly normal 'heptane' (Octane = "O") and you then have to add an octane equivalent back to the blend to slow down the flame speed of the heptane ... better, cheaper, and much SAFER to simply use only fresh ethanolated gasoline, and simply use it in your automobile after its over 30-40 days 'old'. If you dont have the 'specific' knowledge and expertise ... its just too damn dangerous (and highly illegal) for a DIYer to separate ETOH from 'gasoline'.
The question for the immediate future remains when the government imposes E15, which is definitely not going to be not 'compatible' for small and fractional HP 'engines', and 'older cars too' ... the indicators are that government will ultimately not allow sale of anything less than E15 and it will simply follow that anything requiring E10, or less, will simply be rendered 'obsolete' unless one goes to the additional expense of retrofit carbs, etc. with larger 'jets' and 'passages', etc. that deliver the correct fuel/air ratio for E15, etc.
The reason the modern autos dont gum up with E10 is: 1. the fuel pumps are high pressure 'recirculation' type pumps (fuel injection) and action of the continuous pumping 'chops up' and keeps the dropped out phases 'emulsified' 2. automobiles have closed storage systems (tanks, etc.) -- charcoal adsorption canisters, etc. instead of atmospheric 'vents'.
The remedy for all this is 'political'.
