Pontoon Boat & Deck Boat Forum

Hey guys.. I know this is a question that's been kicked around a lot, but i'v read so many conflicting comments on this I thought I'd just see what the consensus among you experienced boaters was..
In a month or so I'll be putting the boat up til next spring.... In the past I have generally ended the season with about a half tank of gas.. So I would put a stabilizer in and forget about it... then this year I read a lot of comments that went back and forth.. some say either run the tank down as low as you can get it then fill up in the spring... others have said fill up and add stabilizer right before you put the boat up for the winter... Those that say fill up claim it prevents moisture from getting in the tank... but then you're faced with 6 or 7 month old fuel at the start of the season.. those that say run the tank down and fill up at the beginning of the boating season tout that you'll be using fresh fuel from the get go.. but then there's the matter of moisture forming in the near empty tank thru out the winter... Just curious as to what you guys that have been boating for years think is the best way to go...

Coming from motorcycles (30+ years) and the forums supporting them (12+ years) and by and large you will find that the consensus there is to store your tank full with stabilizer. Less air space to cause condensation as condensation causes rust as well as oxidizing your fuel. Also I work on large 8K HP boats as an Engineer and while we have other reasons coming into play we also keep our fuel tanks as close to full for the same reasons. Slack fuel oil tanks grow an algae of sorts...

I have the red plastic tanks so I just take them off the pontoon and use the rest of the gas in the cars.

A lot of what you read on the web is old wives tales from the past. Old days boats had metal tanks and they sweat more than the new plastics. So you had more moisture in the gas. I have had boats for almost 50 years and have never had any problem with filling up the tank and adding some treatment or running it dry and filling it up in the spring. But did one thing everytime turn off the gas to the motor and run it dry leaving no gas in the carbs.

Only one time I let it sit for almost 4 years and had it drained before the new season. Just good common sense.

I've had no problem storing mine half full, with stabilizer, but living at 9,000 feet elevation, in the Colorado Rockies, the humidity is amazingly low through the winter. This is a place where you can SEE sublimination happening - that is, water going directly from ice, to vapor without bothering to turn to liquid on the way. It literally evaporates.

Portable tanks that the vent can be closed will not pick up moisture. All my fuel has 10% ethanol that sucks up any water.

I add oil to bring mine to 16/1 for use in the snow blower.

Stabilize whats left.

Im on teecro's side on this.

Thanks guys.. I appreciate the input..

lakerunner wrote:Stabilize whats left.

+1 for Myself and have never had an issue "yet". But we run our boat a lot and go through some fuel over the summer season. As such when we put her away I know the fuel is either fresh or only a week or two old when we put her away. In reading through this post though I remembered another post made by Roland recently that would make me contradict my own advice.

ROLAND wrote:still have a little boating season left down here in Louisiana.... we've been out probably 7 or 8 times this summer.. mostly crappie fishing... so far still have about a quarter tank left from the fill up at the beginning of the season... I assume by the end of october we'll have to put the boat to bed for the winter.

Simply because I'd never consider just stabilizing a bit of leftover fuel that has been sitting around in my fuel tank since spring. In this case I think I'd prefer to be the treat it and top her off boater myself. It just would seem the sinsable thing to do in this situation.

Been boating for 26 years. I fill it and use Stabil.

When I pull my boat out at the end of the season, I fill the tank on the way back from the ramp and add a generous amount of Stabil. You can overdose without problems. The Stabil gets thoroughly mixed with the gas on the ride to my house. When I'm ready to winterize, I warm up the motor (using muffs) in preparation to changing the crank case oil. This allows the Stabil treated gas to go through the carbs.

I add Starton Blue to every fill up, but at the end of our season, I add Statron Blue, take 'er for a good run on the bay and then top off the tank on the way home.

badmoonrising wrote:I add Starton Blue to every fill up, but at the end of our season, I add Statron Blue, ......

Me too. Good stuff !

My two cents........... No fuel in tank = no alcohol = no problems.

From mercury's web site:
Question:
What should be done when storing boats with ethanol-blended fuels for extended periods?

Answer:
Follow the instructions for normal storage preparation found in the Operation, Maintenance & Warranty manual.When preparing to store a boat for extended periods of two months or more, it is best to completely remove all fuel from the tank. If it is difficult or not possible to remove the fuel, maintaining a full tank of fuel with a fuel stabilizer added to provide fuel stability and corrosion protection is recommended. It is best to add the stabilizer and fuel treatment to the tank at the recommended dosage, run the engine for 10 minutes to allow the system to be cleaned, shut off the fuel valve to interrupt the fuel supply and allow the engine to run until it stops, and top off the tank until it’s full to reduce the amount of exchange with the air that might bring in condensation. Do not cap the tank vent and do not fill with fuel to the point of overflowing. Some extra space should be maintained in the tank to allow for expansion and contraction of the fuel with temperature changes. A partially full tank is not recommended because the void space above the fuel allows air movement that can bring in water through condensation as the air temperature moves up and down. This condensation could potentially become a problem.

Yamaha's site says leave tank 7/8ths full after running treatment through engine.
Volvo-Penta said empty tank if possible.

Still a confusing mixture of recommendations, but seems the best bet is no fuel. If you do leave full in tank, then tx the hell out of it. I treat every tank all year just in case something happens where I can't run the boat for several months. I'm older and shit happens...........

I'm older and shit happens

No shit! I have lost all of my super powers. I've learned that even if I remember something I forget it again. Treat it when you fill it!