What happened to my 1 year old dinghy fuel?

[Woodstock]

I bought a new 10' AB RIB in early 2020 and put a new 15hp Tohatsu motor on it. Spent a month getting it prepped for the boat including installing a new fuel line and tank (with ethanol free gas) that was in a bow compartment of the RIB. Ran it one time on a hose in the driveway last April and it ran great. When covid hit last spring we put our travel plans on hold so the dinghy sat until today. I started it up today and it cranked right up but died after about 20 seconds. After investigating, the fuel in the engine was dark red almost bordering on molasses color. But the fuel in the tank looked normal so I was able to bleed the bad fuel out of the hose and the engine and get it running. So it appears that only the gas that sat in that new fuel line is what went bad. Is this just a bad fuel line? What would cause this?

 

[rslifkin]

If the gas wasn't stabilized, any of it that wasn't well sealed from air exposure would definitely go bad. In general, any gas that won't be burned within a month should be stabilized. And stored in a well sealed container.

 

[SteveK]

OK, but why did fuel in the line go bad, no air there

 

[Woodstock]

OK, but why did fuel in the line go bad, no air there

Exactly. Only the fuel in the line between the tank and the motor went bad.

 

[koliver]

Exactly. Only the fuel in the line between the tank and the motor went bad.

Over the last few years, I have been trying to get away from ethanol laced fuel for my dinghy. last year I started having some problems with my 18 yr old Honda 40, carburated outboard. I ended up using a spray can of Honda Carb cleaner, and it has run well since then.
For the winter, I ran out the fuel in the carburetors and it then sat for 6 months.
This spring I reconnected the fuel line and started it up. It runs perfectly well. The secret seems to be the fuel. No ethanol. 91 octane with a sign on the pump that says "0% ethanol".

 

[psneeld]

Ah the myth about Ethanol gas. I have been using it for over a decade with many others with no problems.

Non ethanol fuel goes bad to if not stabilized and or under certain conditions.

Both fuels will evaporate and screw up carbs with varnish like deposits.

Yes Ethanol can phase separate and turn into a mess, but once learning its weak points, no big deal. But having non ethanol gas doesn't mean trouble free, there were plenty of gas issues long before Ethanol arrived.

My 8hp outboard has run perfectly too for the last 10 years with Ethanol...in fact great as the Ethanol is a great solvent to prevent varnishing. But leave it in the carb for more than a couple months....yep, little flakes where it dried up just like non ethanol gas. So I run it dry and no problems.

 

[backinblue]

Ah the myth about Ethanol gas. I have been using it for over a decade with many others with no problems.

Non ethanol fuel goes bad to if not stabilized and or under certain conditions.

Both fuels will evaporate and screw up carbs with varnish like deposits.

Yes Ethanol can phase separate and turn into a mess, but once learning its weak points, no big deal. But having non ethanol gas doesn't mean trouble free, there were plenty of gas issues long before Ethanol arrived.

My 8hp outboard has run perfectly too for the last 10 years with Ethanol...in fact great as the Ethanol is a great solvent to prevent varnishing. But leave it in the carb for more than a couple months....yep, little flakes where it dried up just like non ethanol gas. So I run it dry and no problems.

You are correct. Ethanol-free gas can still cause problems and leave deposits when dried out. I found out the hard way in a new small outboard, which is why I now have gone electric. Coincidentally, I'm also making the transition to electric lawn tools. Just gave up on my old Craftsman 2 cycle hedge trimmer and bought a rechargeable Dewalt. I'll buy more electric attachments when needed.

 

[rslifkin]

The fuel line is probably slightly more permeable than the tank itself, so over the course of a year, the gas in the line lost some of its volatile components. Outboards don't always get the same low permeation fuel lines that inboards do.

Ah the myth about Ethanol gas. I have been using it for over a decade with many others with no problems.

Non ethanol fuel goes bad to if not stabilized and or under certain conditions.

Both fuels will evaporate and screw up carbs with varnish like deposits.

Yes Ethanol can phase separate and turn into a mess, but once learning its weak points, no big deal. But having non ethanol gas doesn't mean trouble free, there were plenty of gas issues long before Ethanol arrived.

My 8hp outboard has run perfectly too for the last 10 years with Ethanol...in fact great as the Ethanol is a great solvent to prevent varnishing. But leave it in the carb for more than a couple months....yep, little flakes where it dried up just like non ethanol gas. So I run it dry and no problems.

Agreed. My boat ran on nothing but ethanol gas for ~15 years. Only reason it isn't still is a change of location where all of the fuel docks near me now have only non-ethanol.