Question for the outboard users, how many run the fuel out of the system at the end of every day's use? I use to do this years ago and stopped when somebody claimed the residual fuel in left in the cylinder from the shutoff protected it from short term corosion. I still due this on smaller engines like gas powered generator, pumps etc and have had great results. Thougts??
outboard question
- Thread starter Gerald N
- Start date
I guess I've never understood why anyone would want to "run the engine" to drain the fuel system. I can understand that there are reasons (some good some not so good) to drain the fuel sytem but why do this by running the engine? (other than the convenience factor)
Running the engine until it is staving for fuel and lubrication (if two cycle) is IMHO never good for it. Do you do the same with your car engine when you park it for the night? Of course not. So what make a boat engine or a lawnmower engine any different?
Long term storage or the need to tip an engine beyond it normal travel are the only times I might feel the need to drain the fuel. When I do drain the fuel, I drain it, not run the engine till it starves from fuel, the fuel ratio is altered and the combustion temperature skyrockets.
Yes, many people run their engines dry of fuel and get by with it. Doesn't change the fact that it is not good for the engine.
Running the engine until it is staving for fuel and lubrication (if two cycle) is IMHO never good for it. Do you do the same with your car engine when you park it for the night? Of course not. So what make a boat engine or a lawnmower engine any different?
Long term storage or the need to tip an engine beyond it normal travel are the only times I might feel the need to drain the fuel. When I do drain the fuel, I drain it, not run the engine till it starves from fuel, the fuel ratio is altered and the combustion temperature skyrockets.
Yes, many people run their engines dry of fuel and get by with it. Doesn't change the fact that it is not good for the engine.
David Ludington
Active member
I use to do that, run motor dry each day, but with c-foam and stabil type products on the market these days I discontinued that practice. I just add a small amount fuel stabilizer designed for marine use to my gas each time I fill up. There a bunch of these on the market, find one you like but check with your motor manufacturer for their input on which might be best for you.
Tom Scholberg
Well-known member
IMHO, Long term storage might be a good idea to store the carb dry, if you are worried about corrosion in the carb maybe you need another place to store your engine. Short term storage (overnight, day or two) reallyno need. The issue of running a two cycle out of oil is more theory than anything else, yes the fuel provides the pre mix oil BUT there is always some oil on the parts. Run one dry and tear down if you don't believe me. Now the issue of fogging for long term storage, great idea, try to do it but don't panic if you forget or deer season opens before you get it done. Like Dave says people get by with all kinds of stuff which is a testament to how well these engines are built. Oh yeah, if you do decide to run a two stroke out of gas, do it at an idle please- your engine will thank you. As you can see it is another ? with no one right answer
How about the small outboards with an integral fuel tank? I have a 2 stroke Tohatsu 3.5 hp that generally runs like a top.
I store all my fuel tanks full, with Stabil, and sealed tight. I figure less air in the tank means less opportunity for moisture in the air to get into the tank.
I've always topped off my little motor's fuel tank with a bit of extra rich (40:1 instead of the called for 50:1) fuel/oil mixture when I store it for the winter, and I top it off after every trip during the season.
Should I run the tank dry and store it empty instead? Do other people with these run them dry every trip, or not worry about it?
I store all my fuel tanks full, with Stabil, and sealed tight. I figure less air in the tank means less opportunity for moisture in the air to get into the tank.
I've always topped off my little motor's fuel tank with a bit of extra rich (40:1 instead of the called for 50:1) fuel/oil mixture when I store it for the winter, and I top it off after every trip during the season.
Should I run the tank dry and store it empty instead? Do other people with these run them dry every trip, or not worry about it?
Nelson Graves
Active member
As you have seen, opinions vary on this topic. Your best bet is to ask your service center, or contact the manufacturer of your engine and ask them. I did, and this is what I came up with. Two stroke and four stroke carbureted outboards, running ethanol laced fuel, I always run dry after every use. I never run fuel injected outboards dry, it will damage them quickly. I try to only run non-ethanol laced fuels in them instead.
Some good fuel additives can mitigate some of the damaging effects of ethanol laced fuel and prolong storage life, but not by much. Some outboards have fuel passages containing dissimilar metals. The alcohol in todays gasoline can create an environment ripe for galvanic reaction between those metals, causing damage during extended storage and clogged fuel passages.
In addition, many older outboards contain non-metallic components which may shrink, swell, or just deteriorate when in prolonged contact with ethanol laced fuels. Running the fuel out of the engine may delay but not eliminate some of of these problems.
Some good fuel additives can mitigate some of the damaging effects of ethanol laced fuel and prolong storage life, but not by much. Some outboards have fuel passages containing dissimilar metals. The alcohol in todays gasoline can create an environment ripe for galvanic reaction between those metals, causing damage during extended storage and clogged fuel passages.
In addition, many older outboards contain non-metallic components which may shrink, swell, or just deteriorate when in prolonged contact with ethanol laced fuels. Running the fuel out of the engine may delay but not eliminate some of of these problems.
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