Best fuel to run thru boat motor?

[Murdock]

I live in the Southern metro, looking for a near-by station that has non-oxyginated fuel available. Is this the right/best fuel to run thru your boat motor and if so, does anyone know where a guy can find a place that provides this type of fuel? ( I have a 35 horse Yamaha tiller on my boat.)

[Gissert]

Fleet Farm has un-oxygenated fuel (Lakeville).

[Fish-n-Freak]

That is the right fuel to use, and I know on the north metro I get mine at Super America, Amoco and a local little store. I think the Holiday stations have it also.

One other thing -- ALWAYS run your motor dry, if it is going to sit for more than a couple of days. Any of todays gas left in the motor will trash it in about 2-3 years. Then you get to pay $600 to get the injectors replaced and carbs cleaned.

Good luck with your search.

[Guest]

OK...so just unplug the gas line at the tank or motor? and then let die before pulling it out of the water? I have never heard that before.

[EBass]

I never heard that before either. But I just got a boat back in July so doesn't surprise me.

[can it be luck?]

I also run my motor dry after each use. Unplug the line and let her run.

[Surface Tension]

If you have a small engine that doesn't get used often or used seasonal it's best to use unoxygenated gas with a stabilizer.

I've got mixed feelings on running the carb dry. If you mix your gas/oil and run your carb dry your also running the crank and cylinder walls dry. Moister and lack of lubricant in a stored engine is the main reason for bearing pitting and piston cylinder wall rust. A little rust on a crank bearing will get you about 2 hours of use till it's shot. On the other hand a dirty carb will make and engine run lean which can damage rings, piston, walls and bearings. For short periods of storage I'd say go with a stabilizer. For extended storage use a stabilizer and fog the engine. To fog properly you do so with the engine running, you'll find the instructions on the spray can. After I'm done with the fogging I like to remove the plugs and spray down the cylinders.
Now if you like the bowls dry, drain them manually.

[Gissert]

I have had good luck running Seafoam in my small motors that are used infrequently, say once every two or three weeks. It stabilizes fuel, and prevents gumming.

Any longer terms storage that that, I fog the engine.

[Murdock]

Thanks for all the info guys.I visited a station that is on the Unoxyginated gas listing. I maybe blind, but am I to look for a specific pump or should I be looking at the octane level? I think I need to look for the higher octane gas, but not certain.Can someone please reply with direction as to what to look for at the pump? Thanks tons guys. By the way, I have found using Seafoam as a stablizer seems to do a better job then many other stablizer products.

[Gissert]

Unoxygenated fuel will usually be the highest octane. If a station has it, it will be a single pump, and will be labled as unoxygenated fuel for use in small engines and older vehicles.

Look closely, as there may be other pumps there of equal octane rating that are oxygenated fuel.

[can it be luck?]

Mercury Quicksilver gas additive is what I use on any fill up, expensive but worth it to me.

[Fish-n-Freak]

I'm not a motor tech, just forwarding what I was told by techs at Nelson and Hallberg Marine. I have a 1999 Honda 90hp Tiller and ran it fine for about 2 1/2 years with Seafoam and other additives, but never ran her dry after each use. I had my boat in the shop most of this spring trying to clear up a problem with the mid-range RPM's and then once the mid-range got cleared up, I had NO top end.

I got the carbs cleaned and injectors replaced and was told to make sure and run the gas out, after each use, if the motor would sit for more than just a couple days before the next use.

I was told that "todays gas is just poor quality, and varnishes quickly in the carbs". I still use the Seafoam and stablizers, but I run it dry after each use. I don't know if it will cause other problems, but I would rather not go through the carb prolems again. I will see what the next couple of years bring, and if I go back to the shop for any other issues.

My current pattern is to run it dry at the lake, and then (at home) I pull the plugs and shoot a quick shot of fogging oil into each cylinder -- to provide lube and prevent rust. Only got a three month track record, but so far it's working.

Wish we had a Motor Rep or Tech to answer this one.

[Surface Tension]

No way will a carb varnish in a couple days. If it did you'd see cars stalled all over on the road side.
Only reason to run it dry is cause most guys arent sure when they'll get out again.
Running a 4 strokes and oil injected engines dry is fine.

[Steve Foss]

Yeah, I doubt it when I hear that today's gas is worse quality than it used to be. I can't image you'll get carb varnish that fast. Sounds like a mechanic who is covering his rear in case his fix isn't right.

But if the non-oxygenated gas is the higher octane, how could it be we should run that in our small motors? I've been hearing for years that small engines are designed to run on normal octane gas, and high octane stresses them.

------------------
"Worry less, fish more."
Steve Foss
[email protected]

[united jigsticker]

Running the carbs dry on pre-mix applications is not good for the motor, as previously stated. The cylinders will need fogging to prevent rusting, even if storing for just a day or two.

Oxidation on unprotected high friction metal takes place fast, especially in summer weather!

On injected motors, the oil is injected at the carbs. So basically when the gas runs out, the engine kills, and oil quits pumping. Oil may be injected a split second longer, but odds favor the majority of it will remain in the carbs. Over long storage times, slight amounts of sludge can develope of some of this residual oil and plug orfices and jets, and your cyclinder walls will still be dry and end up oxidizing.

By "running the motor out of gas" you still leave residual fuel in the carbs, in nooks, crannys, orfices, where its not wanted. The less gas in there, the quicker it goes stale and varnishes.

The best way is to treat the gas with a good additive, for short or long term storage.

Sea-Foam or Sta-Bil will work well, but make sure to run the motor long enough after treating the gas so it makes it through the fuel hose and the carbs and the motor fires off on the treated gas. This way, you can leave the carbs full, and shut the engine down normally.

For long term storage, pull out the plugs, shoot a 3 second shot of fogging oil in each cylinder, and turn the engine over for 3 seconds with the plugs out. Replace the plugs, and she is good to go.

On short term storage, fogging is not required, as the cylinders have enough oily residue to prevent too much oxidation to cause harm. However, keep in mind that over time with the motor tilted up, enough of the oil could run back to create vacant areas of petroleum protection on your cylinder walls.

After writing all this, it seems pretty outrageous, as most people don't even think of any of this stuff and never have a problem. 1,000's of hours, year after year, and life is good.

On the note of gasoline and octane ratings...Octane is a measurment of fuels resistance to burn. The higher the rating, the more compression and hotter spark it will require to ignite the fuel.

Most engine manufacturers state the use of 87 octane fuel.

Ufff Da. I am winded now.

------------------
Good fishing,
UJ
[email protected]

[This message has been edited by united jigsticker (edited 08-24-2003).]

[Dano2]

So should a guy add the proper amount of sea foam EVERY time he fills up? If he takes the boat out say, once or twice a week?

[This message has been edited by Dano2 (edited 08-24-2003).]

[Surface Tension]

Dano I put a stabilizer in if I think I wont be using the gas up in the tank within a couple weeks. It shouldn't hurt to add stabilizer whenever you gas up.