Marinette Boat Forum

I'm looking for some information regarding a constant topic of discussion at our marina and is not specifically related to our M's. With the price of fuel, many boat owners find that they may not run through a full tank of gas during our short Great Lakes season. Old gas, plus low hours, equals TROUBLE! Sooo, I was looking for some thoughts on how to mitigate this issue. I submit the following questions for discussion:

How bad does gas have to get before you should have it removed instead of burning? I know the best solution is to remove old, "bad" gas and replace with new, but that is a costly and complicated process. Is adding fresh fuel and running it through an acceptable solution?

A previous post indicated that most additives aren't worth their own press, but are there any additives that can help "restore" a bad fuel load?

I must admit, I have run some pretty dirty gas through my Chryslers, but have always ended up working the problem out. Is there a way to tell if you fuel is simply too contaminated to run it through?

How do you mitigate sediment problems as they always seem to be an issue with Great Lakes boats?

I know there are some great motor minds out there. Can you please weigh in?

Thanks,
Scott

I added a gallon of "Seafoam" when I filled up 2 yrs ago. About 80 gallons. Says it stabilizes gas for 3 yrs. Boat was winterized and sat idle till this year. Both motors fired up and run fine. They're die hard 318's.

I took very old gas out of my boat tanks, treated it with PRI-G and burned it in the 318 in my fuel injected pickup truck. My boat tank gas is now about two years old. It is non-ethanol and should be OK when I refresh it with new gas. I would not use an additive with alcohol in it. If your gas is dirty or has water you can rig an electric fuel pump to pull it through the water separator until it shows no water.

A little bit of water in the fuel isn't harmful but a lot of water is -- of course. The really bad actor, especially in ethanol gasoline is the whitish yellow looking sludge that settles out and then finds its way into the fuel lines. I suspect that siphoning it out from the bottom of the tank will help. Unless you can do that, count on multiple carb cleanings which are either time consuming, expensive or both. The old Perko filters with the ceramic cartridges were great at keeping that sludge out but my newer spin-on units not so good. It looks like Yooper's solution was a good one if you have a truck with a wide appetite.

Use the Fastjeff Burn 'em Out Method. To wit:

Get motor up to temperature and running. Shut off fuel valve. Wait until motor starts to die and pump the HELL out the throttle to keep her running long as possible. Then open the gas valve, start her up, and repeat the above. That sucks out all of that vile "White Gook" that goes right through filters and separators, won't burn, and can not be made to by any know additive.

Jeff

I just had a similar fuel problem, my solution and it seems to be working. The spin on filters were clogged with yellowish brown stuff, I have a aluminum tank. I changed the spins, shut off fuel valve and ran dry. Next I added 5 cans of seafoam also added 5 oz of water zorb. The 318's ran fine but not one to let it alone I pulled the fuel sensor and with a plastic kerosene pump I sucked out about 2 gallons and it looked ok with no water or gunk. I have been using 89 octane ethanol gas and adding valve tech for ethanol. I will now use ethanol free 92 octane hoping this solves any future problems.

Seanik
1987 28" express
twin 318's

This sounds old school and it is !

I run MMO (Marvel Mystery Oil) Been around since the dinosaurs roamed. It helps lubricate displaces water.. and just keeps things running.

I clean my Perkos out and change filters annually. No problems with the big M in 10 years knock knock.... I use MMO in my antique cars which are very sensitive to old gas.. because I do not drive them often enough.

Most of us do not run our boats enough make sure you burn at least a full tank each season before layup.

safe boating,

dave

You put MMO in your gas?

Roger

Yes sir.... 4 oz per 10 gallons

I have found that MMO helps to keep varnishing to a min. in the carb. It is a very good cleaning and lubricating solvent. Smells nice also



dave

I run MMO at a rate of 1 oz per gallon of gas. Lubricates the top end and dispalces water.

I became a fan while racing. During tear down, I noticed engines running fuel with MMO has less piston scoring, fewer valve deposits and better looking rings, valves, etc.

To my surprise, many of the top fuel and pro stock guys were doing the same thing.

Eric.