Fuel revival

[merseybluenose]

Motor didn't perform so well last time out, thinking it might be old fuel as its been sitting for a few months without use and it sits outside so maybe a little water........can I just buy one of those bottles of fuel stabilizer and revive the fuel I got in the tank??

[Axl]

Are you using tote tanks or is it an under floor tank?

If you are able to get the old fuel out do so and use it in the mower. You are putting yourself at risk using old fuel. If you cant get it out then id top it up maybe add some stabilser take the boat out for a good run and use it all up.

If it is water and as you have said "it sits outside" then you need to do something to stop the water getting in and posibly add a water/fuel seperator to your boat.

[stevej]

stabliser only works when added to new fuel

otherwise your just stablising old fuel

[Spaniard_King]

How much fuel are you talking??

What is it stored in??

What engine are you runing??

[merseybluenose]

Sorry, yes its a 70ltr under floor s/s tank, 40hp yam 2 stroke.

When I say its old fuel, I've continually topped it up after taking the boat out meaning there would be some fuel that has been in there for longer than a few months but has always been mixed in with fresh fuel.

The motor could not reach full throttle and was generally down on power/performance..............I figured after checking the sparkies, fuel was the next guess as the boat was fully serviced in the last 6mths.

[tigermullet]

This 'stale fuel' thing had me worried a couple of weeks ago when I went out on a friend's boat. He hadn't re-fuelled or checked his boat engine for eleven months. To my surprise, it ran like a beauty and went like the clappers. Not one problem. I was all prepared and equipped with several flasks of coffee, beer and four packets of smokes because I fully expected to be stuck out on the water for hours. 18 hp Tohatsus - you can't stop em with an axe.

[FishHunter]

It seems to me the statement "It could not reach full throttle" is your problem. Why couldn't you open the throttle all the way?

[merseybluenose]

it was miss-firing, a low burble like that I've heard when not enough oil in the tank and the motor is in life saving mode - only this time there was plenty of oil and I could only reach 2/3 throttle - got slightly worse as the day wore on.

[Crunchy]

Sounds like plugs, but you checked them, how did they look?

[wrxhoon]

Have you checked if the mechanical advance works whe you open the throttle?

[Dignity]

stabiliser only work to prevent fuel going stale, once it breaks down I doubt there is a reliable way to fix the problem, also if it is stale it will ruin your mower (also cheap oil is another way to make your mower smoke). If your motor is running sweet in the lower range then I would start with new plugs etc as per above suggestions.

[Moonlighter]

A while ago we had a marine mechanic talk at our boat club about outboard maintenance. He brought a jar full of "off" fuel with him, because he knew we would all ask him how to tell it was off.

Well, the smell gives it away. It smells bad. Not like normal fresh fuel at all.

So that would be the first test. Lift the lid, and have a smell. If it smells normal, its most likely OK. If its off, you will know by the bad almost rotten smell.

Also, it seems that tanks that are kept full plus boat kept in a garage, fuel keeps much lomger than a half full tank in a boat left out in the weather.

The other thing is water in the fuel. You do have a water separating filter, dont you???

If not, you are, frankly, mad. All engines like fuel that is clean and water free. There are so many reports around of people who pick up a load of dirty fuel or water laden stuff that a decent filter of the Racor type is compulsory.

As others have siad, check the plugs. They should tell you a story, especially if one f them is wet and black and the others arent.

Cheers

ML

[cobiaman]

Back when i had my tinny, i would leave the fuel in my tank for up to a year. Motor was a merc 9.9 and it never run bad or anything...

[joey_1987]

+1 to sounding like plugs. Have had this issue myself.