Gas: Run it All Out, or not..."That is the question

spidc60

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May 30, 2005
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I have a 71' 800 Merc. Question, Is it better to run the gas out the carb right before pulling it out of the lake or not? I tend to use the boat weekly.<br /><br />Thanks
 

Barnacle_Bill

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Re: Gas: Run it All Out, or not..."That is the question

There really isn't any need to. Besides, that doesn't empty the carbs completeley anyway.
 

ZmOz

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Re: Gas: Run it All Out, or not..."That is the question

Absolutely not. Several reasons.<br /><br />1. Completely unnecessary. Gas takes a LONG time to go bad to the point that it will cause any carburetor trouble. Years.<br /><br />2. I don't know your motor, but if it's two stroke and has multiple carbs it is bad for the engine to run it out of gas. The carbs will not run dry at the same time; which means it will only be running on a few cylinders for a time. The cylinders that have already run out of gas will be running without lubrication.<br /><br />3. You will not get all the gas out. The only way to get all the gas out of the carb is to take it apart. The less gas you have, the faster it goes bad. This means running the carbs "dry" actually causes them to gum up quicker than if you just left them full. (but again, this takes YEARS to happen)
 

umblecumbuz

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Re: Gas: Run it All Out, or not..."That is the question

Cutting ignition to stop the engine leaves a gasoil mix unburnt in the cylinders.<br /><br />This is great anti-wear insurance for next time you fire up.<br /><br />Others have their own views, but I would never run the motor dry, even when winterising.
 

walleyehed

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Re: Gas: Run it All Out, or not..."That is the question

I agree with the above info, except this;<br />
Gas takes a LONG time to go bad to the point that it will cause any carburetor trouble. Years.<br />
This can happen in 60 days...."years" no longer hold truw with todays fuel.....<br />If it will set more than 30 days, stabilizer is a must.
 

fishingdan

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Re: Gas: Run it All Out, or not..."That is the question

I have been told to eave them with fuel, but use a fuel stabilizer.
 

jleus

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Re: Gas: Run it All Out, or not..."That is the question

I pump the bulb to fill the carb bowls each weekend if the thing is not headed for the water.
 

lladnarc

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Jun 12, 2005
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Re: Gas: Run it All Out, or not..."That is the question

I failed to "winterize" my rototiller last fall, It was stored in a shed all winter, and upon trying to start it this spring, well it wouldn't. The gas in the carb was FOUL, I'd never smelled bad gas like that (insert chili joke) I had to drain it, clean it, and run a teeny piece of wire through the jets cause they were all plugged up. Once I did that, it started on the 2nd pull.<br />After that happening to me, I'm a fan of the stabilizer route. Even though I'm new to boating, that's my plan for my outboard.
 

Paul Moir

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Re: Gas: Run it All Out, or not..."That is the question

Never happened to me to before last winter. One outboard got stored in a hot furnace room and this spring the gas had gone bad - cloudy and foul-smelling (nose knows!). The fuel was 8 months old and had sat all summer too. <br />Sometimes I run out small single-carb engines by letting them idle until they start to lean out, at which point I pull the choke to slather their insides. Only reason I do this is to get most the gas out of the carbs for transportation.
 

ZmOz

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Re: Gas: Run it All Out, or not..."That is the question

Originally posted by walleyehed:<br /> This can happen in 60 days...."years" no longer hold truw with todays fuel.....<br />If it will set more than 30 days, stabilizer is a must.
Bulls**t. Fuel CANNOT go bad to the point that it will cause carburetor trouble in 60 days. That is simply impossible. Under the worst circumstances it can go somewhat stale, and may not run as good as fresh gas, but it's far from gumming anything up. My old jeep sat for 3 years with 1/4 tank of gas out in the weather. Started right up and passed an emissions test on that fuel with flying colors. I just started up my chain saw for the first time since probably september. Fired right up, no problem. No winterizing what so ever. I could go on, and on, and on.......<br /><br />If you have gas that has gone bad in a few months, you got bad gas, or your tank is contaminated with something.
 

umblecumbuz

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Re: Gas: Run it All Out, or not..."That is the question

Kenny, I guess your view differs just a tad from ZmOz!<br /><br />One thing I've noticed is that temperature seems to make a difference to the aging rate of gas. Colder temperatures let the gas live longer.<br /><br />Whatever the definitive 'operating age' of gas, I would always err on the cautious side. Stabilising older fuel is no big deal - so why not play safe?
 

nightstalker

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Re: Gas: Run it All Out, or not..."That is the question

The smart thing to do is to use stabilizer regardless of how long it takes gas to go bad. Why take a chance??????<br />Stalker
 

TOHATSU GURU

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Re: Gas: Run it All Out, or not..."That is the question

Always run the gas out. The fuel does not go bad so much as the lighter parts of it evaporate leaving you with "varnish, sluge, crap" or whatever you want to call it. You do lose a little octane each day. And there is a minimim amount of octane that you need in order for the fuel not to become unstable. When fuel becomes unstable it can pre-detonate in the cylinders. That is a bad thing. But, the primary reason to run the fuel out or open the drain screws on the carbs, is to keep the jets and passages from clogging shut.
 

Jilly - 5

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Re: Gas: Run it All Out, or not..."That is the question

Just stabilize the stuff. How many gallons are you talking about! Or use Johnson "2+2" in every tank. It's a stabilizer, conditioner, anti-carbon agent, etc. Never run dry or store dry. Gaskets, o-rings, seals, etc all stay expanded and sealing when wet. Dry up the place and you'll leak all over on start-up.
 

Jilly - 5

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Re: Gas: Run it All Out, or not..."That is the question

Jilly - 5 again:<br /><br />Do you drain your cars if no weekly use?
 

jmoser

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May 6, 2003
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Re: Gas: Run it All Out, or not..."That is the question

Have to agree with Elvin here - gasoline is a complex 'soup' of light and heavy hydrocarbons. The lightest HC species evaporate fairly quickly leaving you with a heavier base fuel than you started with. <br /><br />I have had ugly experiences with 2-strokes when the oil-mixed gas gummed up the carb severely.<br /><br />If you are running every 1-2 weekends I would not worry about it but for longer intervals I would run or drain gas out. Its pretty easy to fog at the same time, few extra minutes if you are worried about leanout or storage lube. I feather the choke when running my 2-stroke portables dry, that helps richen up the last seconds of running when fuel mix is leanest and premix lube is waning.<br /><br />BTW: car comparisons are irrelavant. Your fuel injected car has a closed fuel system which severely limits evaporation; the float bowl on your carb is vented directly to the atmosphere via the jets / throttle body.
 

tee-boy

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Re: Gas: Run it All Out, or not..."That is the question

Looks as though no consensus has been reached.
 

ZmOz

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Re: Gas: Run it All Out, or not..."That is the question

Originally posted by tee-boy:<br /> Looks as though no consensus has been reached.
You can argue all you want about stabilizer or no stabilizer...but there are simply no good reasons to run the carbs dry and there are SEVERAL reasons to leave them full.
 

TELMANMN

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Jun 9, 2003
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Re: Gas: Run it All Out, or not..."That is the question

I usually only run the gas out at the end of the year. I also use some sea foam in the tank along with a stabilizer. My orig. 40hp 1978 never had a carb./starter problem and my 1998 40hp merc. and the 2003 50hp merc. classic. are running great.
 

walleyehed

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Re: Gas: Run it All Out, or not..."That is the question

Bulls**t. Fuel CANNOT go bad to the point that it will cause carburetor trouble in 60 days. That is simply impossible. Under the worst circumstances it can go somewhat stale, and may not run as good as fresh gas, but it's far from gumming anything up.
ZmOz, I don't, and won't, hammer you about something you post if I feel it's not quite right, but I will tell you this....Fuel degrades enough in 60 days to cause detonation, carbon build-up and yes, excess varnish...ask Dhadley the same question and see what he says...he won't use fuel over 30 days old.<br />What do you think "somewhat stale" does to the engine while running??? Do you "add fresh fuel on top of what is in the tank and make the fresh fuel bad too?"--Quote from Dhadley.<br />If it's "somewhat stale" it is "somewhat no good".<br />Todays fuel is nothing like it was even 5 years ago...maybe only half as good at best as far as how long it will last in storage.<br />Again, I have no intensions of insulting your knowledge, and I would expect the same from you.<br />Your experience and opinion is one thing, telling me I'm full of Bullsh*t is another.
 
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