Pontoon Boat & Deck Boat Forum

Hello all.. I've been a member on this forum for about 13 years, but haven't posted much lately, primarily because I really haven't used my boat much. In fact the last time she was in the water was the summer of 2020. Since then she's been sitting in a storage building for about 18 or 19 months. Thought about selling the boat but after talking it over with my wife, we think we'd like to maybe go another season or two, which leads me to 2 questions. There is somewhere between 12 and 15 gallons of "old" fuel still in the tank. It's been in there for right at 2 years. I did use a stabilizer when I filled it up 2 years ago, but still. I would hate to get out 10 or 15 miles from the launch and have her shut down because of old gas. Should I go ahead and drain it or just add stabilizer and top it off with fresh fuel? 2ND question is my trailer tires. They don't have a lot of miles on them, but they too have been sitting and not moved in over a 18 months. And they are 5 years old.. air em up and keep using them or just buy 2 new tires for peace of mind. Your input is greatly appreciated. Thanks in advance.

Howdy Roland!

I don't like spending money, but my personal limit on tires is 5 years. My neighbor burns his old gas by adding fresh fuel to the tank, shooting for a 30%-50% new fuel mixture. Two years is likely to be a problem and you will have water in there from condensation. Your separator should take it out, but.....

FWIW, when I got my boat it had sitting for 3-1/2 years. The oil was super clean, the battery was on a Tender, so I wanted to see if it cranked. The engine started immediately and ran smoothly. Everyone around me said to just run it. I drained it of course)

Just my opinion and I am sure that other people will disagree, but I suggest replacing the gas and the tires if you have any real distance and/or high speed to go.

Get some more of those great Caddo pictures!

Ethanol free or with Ethanol? Ethanol free may be ok. I would pull some out and look. But I would probably just drain in either case. Better safe than replacing parts. On the tires I would replace if high speed towing and for a distance. I only tow occasionally for a couple of miles to the ramp at low speeds. If that is how you tow you would probably be fine. Trailer tires should be good for 5 years.

The fuel will be fine especially since you added stabilizer. Top it off with fresh fuel and an optional bottle of Star Tron (which helps rejuvenate old gas and disperse water to burn out) or Seafoam Marine. I've burned even ethanol gas with no stabilizer over five years old without issue. EFI has eliminated a lot of the problems moderately old gas can cause. I bet if you started it right now it would run like you just used it yesterday.

There is no additive that can prevent fuel from losing volatility (ease of ignition) with age once you pass a year. The best thing for that is storing with the tank close to full and keeping it out of sunlight so if yours was in storage that helps. Since you do not have a full tank, topping off with fresh gas will help bring the overall volatility up.

Might need tires soon anyway and you can typically buy the wheel and tire together cheap....or could. I have two spares mounted on my trailer.

On the other hand if you even have an inkling of selling the boat, do it now. It's never again going to be worth as much as it is right now.

This is what I would do if I was in your position;

Drain fuel and use it in a cheap lawn mower or sell cheap to someone with a cheap lawn mower.

If your not going on long trips, just inspect tires for cracks.

Have fun!

Hello Roland--

I would remove fuel and dispose of properly. Fresh fuel with Stabil Marine Stabilizer. NOTE: Honda has it branded for their outboards...that's how good it is.
The potential headaches of using bad fuel are not worth it.
Peace of mind is worth a lot to me; I do my own motor maintenance.

I always tell myself....don't cheap out and don't be lazy!

Marc K wrote: ↑

Sat Mar 26, 2022 5:00 am

Howdy Roland!

I don't like spending money, but my personal limit on tires is 5 years. My neighbor burns his old gas by adding fresh fuel to the tank, shooting for a 30%-50% new fuel mixture. Two years is likely to be a problem and you will have water in there from condensation. Your separator should take it out, but.....

FWIW, when I got my boat it had sitting for 3-1/2 years. The oil was super clean, the battery was on a Tender, so I wanted to see if it cranked. The engine started immediately and ran smoothly. Everyone around me said to just run it. I drained it of course)

Just my opinion and I am sure that other people will disagree, but I suggest replacing the gas and the tires if you have any real distance and/or high speed to go.

Get some more of those great Caddo pictures!

Hello Marc... good to hear from you. as far as the fuel goes, I had given some thought to just towing the boat to the ramp, backing down and firing up the motor while the boat was just sitting on the trailer...thought I might let it run 15 or 20 minutes to see how she runs with the old fuel.. but then I thought that might be a bad idea because if the fuel is going bad then by running the boat I'd be pulling that fuel out of the tank and into the motor.. no question: the safest thing to do for the motor is drain the fuel. The boat mechanic I use told me he could drain it without any problems.. I made a mistake about the tires, they were put on in the spring of 2018, so this would be their fifth season.. Those size tires are fairly inexpensive, think I can two kenda load stars ( that's what's on there now ) for about 175.00 or so. It is about 30 miles one way from the storage building to the lake and almost all of it is highway, so I'm pretty sure I'll just replace them. After not being on Caddo Lake since the end of the season in 2020, I'm kind of itching to get back out there just to see all those beautiful cypress trees.

SoCalAngler wrote: ↑

Sat Mar 26, 2022 3:51 pm

Hello Roland--

I would remove fuel and dispose of properly. Fresh fuel with Stabil Marine Stabilizer. NOTE: Honda has it branded for their outboards...that's how good it is.
The potential headaches of using bad fuel are not worth it.
Peace of mind is worth a lot to me; I do my own motor maintenance.

I always tell myself....don't cheap out and don't be lazy!

Thanks for the replay SoCalAngler.. I appreciate it. I'm familiar with Stabil, it's a good product. However about 10 years ago I stumbled on a product called Pri-G. i've read that some of these large ocean going cruise ships use Pri G in 55 gal. drums for the fuel on these cruise ships. I don't know which one product is better than the other but I only know that since I've been using Pri G in my boat, I've never had a fuel related issue. However, now that the fuel that is still in the boat is two years old, think I'll have it drained while my mechanic is servicing the outboard.. oil, plugs, filters, new water impeller etc... as you know, when you let a boat sit and a couple of years go by, you gotta catch up on the maintenance. Unfortunately, I'm not mechanically inclined like you.. figure the mechanic's bill will be 350 to 400... Ouch.

Hey guys, I appreciate you taking the time to respond to my questions.. thank you all.

Great to hear from you ROLAND! I would probably change tires mine were way older than that when we hauled THE FLOATER to the city and I was spooked the whole time. We got new ones from PS. Wheel and tire.

https://www.pontoonstuff.com/collection ... adial-tire

The gas I would drain most out..

Glad you're getting back on the water! It'll still be a month or so for us.

Going to visit gdaughter in the camper this weekend.

Your boat has been sitting in a storage shed, hence it's not been rained on. You only have a half a tank of old gas. Top 'er off and don't go to the trouble of trying to get the old gas out. It'll run fine.

ROLAND wrote: ↑

Sat Mar 26, 2022 11:57 pm

SoCalAngler wrote: ↑

Sat Mar 26, 2022 3:51 pm

Hello Roland--

I would remove fuel and dispose of properly. Fresh fuel with Stabil Marine Stabilizer. NOTE: Honda has it branded for their outboards...that's how good it is.
The potential headaches of using bad fuel are not worth it.
Peace of mind is worth a lot to me; I do my own motor maintenance.

I always tell myself....don't cheap out and don't be lazy!

Thanks for the replay SoCalAngler.. I appreciate it. I'm familiar with Stabil, it's a good product. However about 10 years ago I stumbled on a product called Pri-G. i've read that some of these large ocean going cruise ships use Pri G in 55 gal. drums for the fuel on these cruise ships. I don't know which one product is better than the other but I only know that since I've been using Pri G in my boat, I've never had a fuel related issue. However, now that the fuel that is still in the boat is two years old, think I'll have it drained while my mechanic is servicing the outboard.. oil, plugs, filters, new water impeller etc... as you know, when you let a boat sit and a couple of years go by, you gotta catch up on the maintenance. Unfortunately, I'm not mechanically inclined like you.. figure the mechanic's bill will be 350 to 400... Ouch.

I’ve been using Pri-G for a lot of years; since well before they began selling gas with ethanol, and it saved me a bunch of $$ compared to my neighbors. Here, the gas stations were given six months from when they started selling “e-gas” to get their e-gas signage up; so all of us had been buying it without knowing it was e-gas.

So, my neighbors were having to have motor work done, gas lines replaced all the way from the belly/other built in tanks to the motors. Many had to have all the internal outboard fuel lines, plus damaged internal parts, replaced.
Since I used Pri-G; I had no problems at all.

My airboat sits for the better part of a year without being used, and I just add some fresh fuel (always ethanol-free in all my boats), even though the airboat engine is a 454 CID 425 HP Edelbrock crate engine, fed by a Holly dual-feed 750 CFM carb.

I’ll be putting my tri-toon back in the water within the next few weeks, depending on the weather, and it’ll be running on the fuel that was put in last September.

PRI-G REALLY IS “ALL THAT!”.