outboard fuel

[JBA]

Hello all

For the winter I plan to empty the fuel tank on my Mercury 5 HP 2 cycle outboard. I have no problem disconnecting fuel lines but I cannot remove the tank even after removing the three securing nuts. I could open the fuel shut down but that would leak fuel all over the place. There is only about two inches of fuel in the tank. Any suggestions?

JBA

[Duncan]

Unless you're going to get rid of the fuel, leaving it in the tank is ok as long as you put some stabilizer in it.

I used to shut off the fuel, run the engine dry while spraying in some fogging oil, and put in a bit of fuel stabilizer.

If you really want to get that fuel out, you could syphon (most of) it out?

[Sea Hunt]

JBA:

I tried searching the web for a service manual for your Mercury 5hp/2stroke. I could not find one. I was trying to see how your onboard/internal fuel tank is configured and the routing of fuel lines.

I am assuming that the fuel line from the internal tank to the carburetor is located at the bottom of the fuel tank. If so, why not just run the onboard/internal fuel tank dry Assuming your O/B is water cooled and that you are "winterizing" the O/B, I assume you are going to flush out the saltwater build up within the "cooling system" before winter storage. Just run the onboard tank dry in the process of fresh water cleaning the cooling system.

If I recall correctly you live in the Maryland area. If the O/B is going to be stored in an area without a lot of temperature changes day and night, leaving the tank empty is probably OK. If a lot of temperature changes then you have the possibility of condensation within an empty tank that you may have to deal with in the Spring.

To minimize the condensation issue you can fill the tank near full (allowing a little space for expansion/contraction of the fuel) and add an extra ration of fuel stabilizer. I prefer Startron but Sta-Bil is also supposed to be good.

[Mike Wainfeld]

Ditto-Leave the tank full with the usual amount of stabilizer added. Been doing that for 13 yrs now-Yamaha 3hp-engine runs great.

[Dick Villamil]

Be careful about leaving old gasoline in the engine - The new fuels are not conducive for storing since they now contain 10% ethanol - and it is not good for the older engines. You should always put into the fuel the alcohol stabilizer whenever using the motor. Then, when storing it you should probably empty the tank by using a siphon and then run the fuel out of the engine. I always fog the cylinder by removing the plug, fogging then cranking the enging slowly to distribute the fogging oil - then replacing the spark plug. You could probably also spray a small amount of fogging oil into the gas tank to prevent rusting over the winter. Stabilizer should be piut into any leftover gas if you are going to store it. The new gasoline only "keeps" for a month or so and fuel stabilizer only lasts for 3 months before the degradation starts - even the alcohol treatment stabilizer. This will only get to be a worse situation if they succeed in adding 15% ethanol! I know of many small engines that have become ruined - or at best clogged - by the ethanol fuel without treatments. Empty the remaining fuel into your car - a little at a time so that the oil burns in small increments until the gas is gone - then buy fresh in the spring and add alcohol treatment to it. Small engines are much more sensitive to bas gasoline then larger lower compression engines.

[Jim Davis]

I have a relatively new 6HP 4 stroke ( but not covered by warranty) that has had to have a new carburetor installed because of Ethanol. This was done after a dozen trips to the shop. Actually two different shops, that were unable to solve the problem. The carb was sent back to the manufacturer and fouling in very small passages due to fuel was confirmed. It could have been rebuilt, but it was cost effective just to replace it.

As a result I replace the fuel every couple months and have learned how to drain the carb, fuel pump, etc. I will give credit to both shops in that after the first trip to each they did not add any more labor charges and really tried to get me running again. I can not blame the problem on dirty tank or fuel lines, both are relatively new and made with Ethanol in mind.

Per my discussions with the manufacturer's head of maintenance support I do add Startron to the gas and for normal use do not run it dry. For the winter I do run the engine dry, then drain it and spray WD40 into the carb, as well as fogging oil into the cylinders.

As to adding alcohol based additives, I would not do it! There is already as much alcohol in the gas as it can support and any more, well you might as well be running E15 (or worse).


http://mystarbrite.com/public/pdf/LIT010V2.1-101.pdf