Running motor out of gas

[Jeffp1]

Hey everyone,
While reading & learning more about outboard motors on this forum, a question came to me.
Most of my boating/fishing life I have owned many outboards, although little ones.(ie:9.9-15hp)
In resent months I now own a 70hp. Over the years when I new I wouldn't be hitting the water for awhile I would unplug the fuel line while the motor was still running,& let it run itself out of gas. I always felt it was a good way of avoiding gum up in the carbs etc. Would this be advisable with a bigger motor such as my new to me 70hp?? Any tips are greatly appreciated!!

 

[F_R]

Re: Running motor out of gas

That is a good question to stir up an argument. There are differing thoughts and opinions. For what it is worth here are mine.

1. I'm old school. Run 'em out of gas at idle is old school, and I'm still there.

2. HOWEVER, one argument is that on multi-carburetor setups you really don't get all the gas out of all the carburetors. It will quit before they all are dry. That thought has merit.

3. There is the argument that running it out of gas starves if of lubrication. I'll never be able to win that argument. But I say phooey. When it runs out of gas it quits. How can it possibly run out of oil?

4. One last comment. If running it out of gas (and oil) at idle damages the powerhead, what happens when you are bopping down the bay at wide open throttle and your 6 gallon tank runs dry? Happens every day and there is no big mountain of junked motors resulting from it.

5. OK, this really is a separate issue, but yes running a motor with one plugged up carburetor on a multi-carburetor engine does deprive the affected cylinder(s) of oil. And/or cause it to run lean which causes damage due to preignition and high combustion temperatures. But that wasn't the question, was it?

Disclaimer: These opinions and $1.65 will get you a cup of coffee at the corner gas station.

 

[JB]

Re: Running motor out of gas

I am with F_R.

 

[bonzoscott]

Re: Running motor out of gas

I always leave fuel in. The length of time you know you're not going to run it is questionable. If 2 weeks no problem. If a month or more, run stabilizer in the fuel. Just my experience and habit.

 

[gm280]

Re: Running motor out of gas

I own a few OBs in my times and I ran everyone of them dry with the fuel line disconnected every time before leaving the ramp(s). And while a few of my collections were single carb'd types, I did the same thing with a 115HP Mercury inline six with multiple carbs as well. I even would push the choke in as it started to run out to get all the fuel I could burnt. I owned that inline six for around ten years and the day I sold it, it would crank so easily that it hardly turned over before running... And that boat would run 63MPH on good water too... So I am with the old school thinking as well. While some say it leave little lubrication in the engine, what happens to the carbs' fuel bowls with fuel remaining in them..? Once that fuel sourers/turns and becomes a serious sticky soupy mess, you have a huge issue with them. JMHO!

 

[metriccrescentwrench]

Re: Running motor out of gas

I've done it both ways, never had any issues. I've even accidentally run my 90 HP Johnson out of gas running at speed a few times (had a 2nd tank ready to hook up) with no ill effects.

I think that maybe this is one area where ethanol in our fuel might be helping. Ethanol is a heck of a good cleaning agent, and I'm guessing that any little bit of lacquer buildup in the carbs gets cleaned very quickly the next time the engine is run.

 

[lindy46]

Re: Running motor out of gas

I've "run the gas" out of lots of motors over the years and never had any ill-effects.

 

[Jeffp1]

Re: Running motor out of gas

Thank you all for the reply!
Considering I tend to side the "Old School" way of doing most things. I think I will run it out of fuel. This method has always been good to me. Besides, the longest the boat sits between trips is about 3 months when Duck season is "A #1". Between Nov. & Jan.
I must say, for all the bad things I could say about my home state.(California) There is a hand full of good!(Year round fishing,great Duck hunting,& Great weather to do them in!)
Take care all!!!!