old gas problem

[pwrln12]

HI all, I just bought a tollycraft 26, with a 255 mercruiser, ran great in sea trials and got it home and ran for a bit then started running bad, we suspect the fuel might be old, but we changed the filters and put some sta bil in the tanks, so far it runs good at the dock but should I change the fuel out? not sure how long its been in the boat?

[Lepke]

If the tank is low, you probably can add new gas and be fine if the engine is running ok now. But I'd use up the tank soon. Fuel conditioner can be used at higher rates. That can help. There are fuel catalysts that can be added that make the fuel burn better. New gas has stabilizers, but they only last about 90 days.

Today's gasoline is even worse than the diesel. It is much more unstable than the fuel 20 years ago. If the gas is going to sit for any time, a few months, and you don't want trouble, it has to have a stabilizer.

[Bentwings]

I’ve run in gas problems as well as others on the pier. I had to go 40 miles on the port engine and through two lock and dams. I’m new to twin engine big boats so it was a challenge. I learned first hand when electronics sign off too. Fortunately I had the river maps. By carefully watching markers we managed until it got pitch dark. Then seeing markers other than the few lighted ones was difficult. I had to read the depth gage with a flash light.

Bad gas also stopped the generator.

I got both motors running when we got home. Both fuel water separators were full.. I saved the gas from the filters. You can see the water then the phase separation level. With the real gas on top. These tanks are baffled so it is impossible to put a hose into the filler other than the bottom of that section. Pumping this gas out and monitoring he phase separation will get most of it but as you go up on plane the bad stuff runs to the rear where the pickups are.

I’m going to make a purge system pulling fuel off at the pickup that I’ll operate at plane and just coming on plane. This should get most of it. Then the best that can be done is to add stabilizer and try to burn off the bad gas. Unfortunately it’s pullout time and I’m down to not more than two weeks in the water. I may be able to drain off some gas on the hard stands if the bow is high enough.

I’ve been on the boat in the last three weeks at night and the amount of condensation is like rain. Everything gets wet.

According to the gas stations gas begins phase separation in tow to three months without stabilizer. It can’t be fixed so you either burn it or pump it. All local marinas sell only non oxy premium gas but it still has some ethanol in it so it will go bad in time.

Asking around, some fill the tank for winter others drain the tanks. I’m not sure which is best.

[pwrln12]

ok we drained 20 gallons and replaced with fresh gas, a pint of sea foam, took it for a spin and it seemed to run ok, so hopefully,,, thanks for your help