Gummy up carb

I just had my carb rebuilt on my 9.9 Mercury 2 stroke. Ran like a top the first weekend. then I let it sit for a month and its hard to start and then dies. The mechanic told me the ethanol fuel clogs up the carbs in about a month of sitting. I cleaned the carb out and now it runs great. (the little needle was stuck) A couple of questions:

1. how do I keep it from sticking again if I am going to sit it for a month?
2. How do I store it over the winter without it gumming up?
3. Is marine sta-bil different than red sta-bil?
4. Is sta-bil effective?
5. Is seafoam effective?

Stabil and seafoam are both good.

If the boat it going to be sitting a month between uses, I would add stabil to the gas every time I filled the tank.

Green stabil is more concentrated than the red. I have a big jug of the red that I have used for a long time without any problems but will most likely switch to the green when I run out.

I use seafoam once a year to help clean things out but keep stabil in the tank for fuel stabilization.

"I use seafoam once a year to help clean things out but keep stabil in the tank for fuel stabilization."

Do (or can you) mix the Sea Foam with gas that already has Stabil in it?

I always run yamaha ring free in my gas..in addition I always run all the gas out after each use...The gas today is very bad for out motors...I also only run fresh new gas in my motor...My yamaha service guy told me the red stabil is junk(not sure if this is true but he sure seams to know a crap load about gas)...he reccomended yamaha's stabil for any gas that will be sitting longer than 3 days but stressed that I always use fresh gas when I can...I just run whatever gas is left in my car,lawn mower ect...

As far as winterizing....just fog the carb real good and that should do the job...at least that has worked for me....

Outdoorsman said:

"I use seafoam once a year to help clean things out but keep stabil in the tank for fuel stabilization."

Do (or can you) mix the Sea Foam with gas that already has Stabil in it?

Click to expand...

Yes, you can mix them.

Longer than three days??? :shock: That would be enough to make me question your Yamaha guy. :lol: It sits in the tank at the station longer than that before you pump it. I've had gas sit in a tank for 4 to 5 months between uses with Stabil (and many times without) and never had a problem... knock on wood.

Yamaha guys push Yamaha, Merc pushes Merc, etc, etc. Any of it is better than nothing and I suspect most of it provides pretty equal protection.

eta: it's not really the ethanol that gums your carbs. It's the residue from the ethanol dissolved parts of your fuel system and gaskets that gums up your carbs. Ethanol loves to eat plastic and rubber that wasn't designed to withstand it and it also loves to water load your fuel. When it reaches it's saturation point it can phase separate and leave you a nice layer of water on the bottom of your tank with the gas floating on top. There's not a gas treatment out there that will neutralize that problem that I am aware of. That's where the water separating filters come in.

Good points and I agree....

I've had good results with Sea Foam and Star Tron.