BajaNomad

Q: Gas for small outboard (again)

Alm - 8-12-2015 at 12:34 PM

Bringing a small outboard. Suzuki 2.5 HP, 4 stroke, carburetor, one cylinder. Very small carb and cylinder.

The manual says "alcohol-free unleaded gasoline whenever possible, with a minimum pump octane rating of 87 ((R+M)/2 method)". Have never heard of R+M method, don't ask me what it means.

I'm hearing all the time that all gas in Baja is ethanol free. So - cheapest Magna then? I'm (mostly) in BOLA area.

55steve - 8-12-2015 at 02:04 PM

R = Research Octane Number, one kind of octane test

M = Motor Octane Number, a different kind of octane test

Average the two (R+M / 2) and that's what they put on the pumps (eg, 87, 89, 93)

Much of the rest of the world just uses RON (Research Octane Number).

Bottom line is that yes, the cheaper fuel in BoLA would be fine but with a tiny engine the cost of the more expensive fuel may not be an issue.

SlyOnce - 8-12-2015 at 02:50 PM

outboards are all very low compression and run fine on the lowest grade of gas. Especially the small ones.

bajabuddha - 8-12-2015 at 03:20 PM

Just a suggestion: I was told by both a dealer and a 4-stroke certified mechanic to ALWAYS run the low-mix Stabil in every tank (Yamaha has their own brand as well) and if your motor is going to sit for more than a couple of days without running, be sure to run the engine dry (and de-salt). I'm not a motor-head, so just passing on what I heard from the pro's.

Alm - 8-12-2015 at 04:24 PM

Thanks.

Yes, I (usually) de-salt and run it dry every time. Darn thing runs 5 minutes on few drops remaining in carb, with fuel c-ck closed :) ...

Sta-bil is a light-duty carb cleaner, adding it once in a while would make sense, not sure about "every tank". But I'm not a pro either.

bajabuddha - 8-12-2015 at 04:32 PM

From what I understand, Sta-bil is a substance that keeps gas from going 'lacquered' on you. In what's left of my head it means gas will evaporate leaving stronger solutions of bad stuff you don't want to build up, and especially in carb tanks, etc. I use it all the time in my 'little tank' of gas for my generator (and back in The Day for my chainsaw, lawnmower, etc). I haven't heard of it causing any damage, so it's worth the few cents for engines that aren't often used. Doesn't clean anything; just keeps it from getting sticky and plugged.

I think.

woody with a view - 8-12-2015 at 04:33 PM

^^^pretty much^^^

Alm - 8-12-2015 at 06:27 PM

Different mechanics are telling different things. Like Stabil is best for fuel conservation, i.e. in storage. To prevent fuel breaking into fumes and gunk after a month or two. And that it does contain water removers and cleaners. Same things I hear about Seafoam, Exact formula of either product is a trade secret, so we'll never know.

If Stabil is not a cleaner (not a heavy cleaner for sure), and is good for conservation - then I don't need it in motor tank. It's a 1/4 gal built-in tank, refilled with a new gas few times a week. Carb is empty. Where I could need Stabil, is in a gas can - if it's not going to be used up in under a month.

basautter - 8-12-2015 at 07:15 PM

The biggest problem with alcohol in fuel is that it can erode gaskets and O-rings. The next is alcohol absorbing water, and algae growing in the tank. I know this from personal experience.

I recommend running your engine dry of fuel between uses if possible. Fuel stabilizer will likely help the algae issue, but not the o-ring issue.

Marc - 8-13-2015 at 06:23 AM

Quote: Originally posted by Alm  
Thanks.

Yes, I (usually) de-salt and run it dry every time. Darn thing runs 5 minutes on few drops remaining in carb, with fuel c-ck closed :) ...

Sta-bil is a light-duty carb cleaner, adding it once in a while would make sense, not sure about "every tank". But I'm not a pro either.


That's what I do with my Nissan 4hp. Use any low octane.