Run gas out after use?

[Uniflite32]

I've got a 1973 65 HP Evinrude, 1994 4 HP Evinrude and a 1997 9.9 HP Merc. I've been told to run the fuel out of the carbs after each use to keep varnish build up down. Is this OK to do? Does it hurt the motor on cold start since there's no lubrication from the fuel?

 

[Xcusme]

Re: Run gas out after use?

I'll usually run fuel treated with stabil at the end of the season with the fuel line disconnected until motor stops. During this last running, I spray fogging oil into the carb throat. You'll never get the carb completely 'dry'. During the boating season, I don't bother to runout the fuel as I use my motors often. <br /><br />No harm is done upon re-starting, pumping to prime carb pushes oil laden fuel mix to the carbs anyway, so the motor always has lubrication.

 

[tmcalavy]

Re: Run gas out after use?

There are mixed opinions on this. One school says running the carbs dry causes wear on the cylinder and rings/piston since it is operating without lubrication during its last gasps before dying. Others say they have done it for years with no bad results. It will deprive the cylinders of lube on a following cold start unless you pump up the bulb to fill the carbs before restarting. I'm lucky enough to have a 57 Johnson 18 hp with a glass bowl filter. I unplug the fuel line at the tank and let it run until the gas in the carbs is exhausted. Then I pull the glass bowl on the filter and let it drain before I put it up for the winter...I also fog the cylinders at this time. When it goes back into service in spring, I pull and clean the plugs, squirt a little premix in the cylinders, reinstall the plugs, hook up a fresh tank of premixed fuel/oil and fire it off. It's almost 50 years old and still running strong, if that tells you anything. Guess it's all a matter of personal preference.

 

[BF]

Re: Run gas out after use?

On my small 2 cyl, single carb'd engines I run them dry whenever they're not gonna be used for a week or two, or if I am going to pull them off the boat to carry them anywhere (lay them down etc). Then I'd rather have the bowl dry. I don't believe the lack of lube thing for this type of engine.<br /><br />I don't run the multi-cylinder, multi-carb'd engines until they die... In those if there is some variation in the float settings, some carb might run out of fuel quite a bit before the others. Over the long haul, I could see how this wouldn't be good.<br /><br />I've had problems in chainsaws and weedeaters (in which the fuel pump/carb are one unit)... Not from varnish, but leaving them with fuel sitting in the fuel pump side of the carb seemed to make the diaphram deteriorate quickly. Now I run those dry after every use, and haven't had a problem in > 2 years. Before this, I always seemed to either be tinkering with the carb, or going to get another carb rebuild kit.

 

[rwise]

Re: Run gas out after use?

I run stabil year round and don't worry about it!

 

[Vic.S]

Re: Run gas out after use?

I agree withrunning the gas out if an engine is not going to be used for a week or so. You will only be doing it at idle speed or a bit above and under these conditions they are over lubricated (VRO cuts the oil down on those models) so I dont believe there is any lubrication problem. If you ran them dry at full power there might be.