Disconnecting fuel line when shutting down motor?

Fishy4U · 03-29-2010, 08:13 AM

Any tips on whether or not to run the motor out of gas after use to drain the carb? (8 hp 4s Merc) For instance, after every time, or only when stored or not going to be used for a while? Any thoughts would be appreciated.Thanks.

BrassMonkey · 03-29-2010, 08:39 AM

Drain after every time.

Redarrow · 03-29-2010, 08:43 AM

We drain our 25 horse mercury at the end of each duck season. When it is going to be used on a weekly basis it is not necessary. Just unplug the fuel line while the motor is running and let it run out. Make sure to buy all new fuel or at least add a stabelizer to any remaining fuel that wont get used for a while. I learned the hard way with my mercruiser 350 and have gone through fuel filters like nobodys business.

freeflyinmane · 03-29-2010, 08:45 AM

When fishing every day, I never run the gas out but I also add marine Stabil to every fill-up. If I am taking a few days off, then I flush the cooling system with fresh water while running out the gas. Hint: If you push in the small pin located on the fuel hose fitting on the motor, it will also clear out old fuel in the line leading from there to the carb. I do this right after I pull the choke out when the engine starts to slow down. I usually use a pen or even my cigarette lighter, un-lit of course, to hold the pin in. The engine will run a bit longer and then you are fine for even long-term storage.

Fishy4U · 03-29-2010, 08:57 AM

Thanks for the responses. Some good ideas.

marthagofish · 03-29-2010, 09:07 AM

What do you to your larger outboards?

DirectDrive · 03-29-2010, 09:09 AM

I used to religiously run mine out of fuel after each trip.
If I'm going daily or weekly I don't do it anymore.....it hasn't mattered in my experience.
For long term storage, yes, drain it. I think that the tank bulb will last longer too, if it is drained prior to long term storage.

fishkisser · 03-29-2010, 11:23 AM

I never run my T-8 out of fuel and keep the fuel line hooked up most of the time ...
All my fuel gets treated , I had problems with the jets getting coked up
draining the fuel so I don't do it anymore ...
I do carry a spare fuel line at all times and 2 fuel filters for every application
on my boat just in case ...
Also carry a 3 gallon fresh tank just in case ... paranoid ... You bet ...
Ever stranded because of bad fuel or plugged filters ... Not yet ...

Fishy4U · 03-29-2010, 01:53 PM

Thanks for all the input everyone,I do appreciate it.

budnate · 03-29-2010, 03:39 PM

thats old school grandpa thinking....think about this guys with a 2 stroke lets run it till it pulls all the fuel out of the motor till it sputters and dies and go park it, now you have left the rings, bore and crank with very little gas/oil for protection.....anyone know what happens to raw steel in a NW damp environment?

run sea foam or what ever stuff you like year around in the gas and just shut it down when your done, over the long run the motor will have less issues.

Fishy4U · 03-30-2010, 08:29 AM

I have been hearing a lot about that Seafoam stuff,and think I might pick up a can to try it out.

ondarvr · 04-01-2010, 02:47 PM

Pulling the fuel line off and letting it run until its stops does not drain the carb, it only lowers the level of fuel in the float bowl, you need to remove the drain plug to actually empty it. But you do end up with a lesser amount of fuel (oil) in the motor where its needed to help prevent rust and corrosion. When you run it dry on a multi carbed engine, some carbs will run dry before others as the motor continues to run, possibly creating other issues.

After saying this, many people run them dry and others do nothing but turn off the key and both claim to have few problems.

Edit; After reading it again you said 4 stroke Merc, so the oil thing means nothing, but to remove all of the gas you do need to actually remove the drain plug on the float bowl.

Fishy4U · 04-02-2010, 08:40 AM

Quote:

Originally Posted by ondarvr

Pulling the fuel line off and letting it run until its stops does not drain the carb, it only lowers the level of fuel in the float bowl, you need to remove the drain plug to actually empty it. But you do end up with a lesser amount of fuel (oil) in the motor where its needed to help prevent rust and corrosion. When you run it dry on a multi carbed engine, some carbs will run dry before others as the motor continues to run, possibly creating other issues.

After saying this, many people run them dry and others do nothing but turn off the key and both claim to have few problems.

Edit; After reading it again you said 4 stroke Merc, so the oil thing means nothing, but to remove all of the gas you do need to actually remove the drain plug on the float bowl.

Thanks for the info

Redhawk-Driver · 04-04-2010, 05:27 AM

Quote:

Originally Posted by Fishy4U

I have been hearing a lot about that Seafoam stuff,and think I might pick up a can to try it out.

Hmmm, SeaFoam ... LUV it!!

dsilvery · 05-23-2010, 09:22 PM

I have ran my engine till it shuts off after every trip out. I have never had any issue with starting by doing this.

On my last trip out I have always put Stabil in my last tank of gas and then disconnect the fuel line after I come in and let the engine run till it shuts off. By doing this the remaining fuel in the fuel bowl will have Stabil mixed in.

Pelagic Captain · 05-25-2010, 08:36 PM

My 98 25hp. merc was in the shop several times ...the shop kept saying bad gas..I keep my gas fresh..it was the merc. I started running the gas out every trip and from then on nary a problem ..that model of merc. had a problem with flooding..after sitting for a week the engine would load up and just would not start ...

jackr up · 06-12-2010, 09:16 AM

what has worked for 20+ years...

if using with in a week, no disconnect and run out,

if not using with in a week, disconnect, purge air at connector so fuel pum can continue drawing as much fuel as possible from lines and into carbs, allow carbs to run untill the pick up tube for jets get pulled dry, this assures the jets are not submerged in old fuel. and run out of fuel...

20+ years of doing so, never had to rebuild a single carb on any engine ive owned, and never had a fuel related issue...

i also store empty as in no fuel in tank, and also remove the drain plugs on the bowls every winter to ensure the bowls are totally empty.. and generally only get a few drops out of each when i run the motor untill it stops with the lines disconnected.

Connelly · 06-12-2010, 10:27 AM

2-strokes run on gas and oild mixed. Run it out of gas you run it out of oil. I dont think its a good idea to run a motor out of oil.

So...

Fuel rots or looses octane after about 3 months. Turns to varnish. The reason people run a motor out of fuel is to keep the fuel from rotting. Running it out of fuel does not clean the fuel out of the tank, fuel line and the rest of the fuel system. But it does create a void in the fuel system, due to lack of fuel, and creates the oppertunity for condinsation/water and fuel rotting.

If you were not going to run your truck for a month would you run it out of fuel?

If you are going to store your motor for more than 3 months clean out or replace all fuel filters, treat the fuel and let it run thru the fuel system. Top the tank off with fuel/fuel treatment and leave no void or air space. Store up right and dry in a dry area.

Air, at least around these parts, has moisture in it. Condinsation. Fuel always rots with out treatment regarless of how small the ammount.

jackr up · 06-12-2010, 12:36 PM

at an idle the lack of fuel and oil in a bowl has never caused an engine failure in a 2 stroke... even the last drops of fuel going into the engine has to pass through the crank case, thus lubing the assembly, it shuts off because the piston cann no longer pull in a fuel charge in large enough quantity to push the piston down and back to the next firing..

Tinman · 06-12-2010, 01:28 PM

Quote:

Originally Posted by jackrup

at an idle the lack of fuel and oil in a bowl has never caused an engine failure in a 2 stroke... even the last drops of fuel going into the engine has to pass through the crank case, thus lubing the assembly, it shuts off because the piston cann no longer pull in a fuel charge in large enough quantity to push the piston down and back to the next firing..

Correct for a single-carb engine. If you have more than one carb, then some carbs are going to run dry before others, which means some pistons are still cycling with no oil at all.

Flatfish · 06-12-2010, 01:30 PM

Quote:

Originally Posted by jackrup

at an idle the lack of fuel and oil in a bowl has never caused an engine failure in a 2 stroke... even the last drops of fuel going into the engine has to pass through the crank case, thus lubing the assembly, it shuts off because the piston cann no longer pull in a fuel charge in large enough quantity to push the piston down and back to the next firing..

True. But the vast majority of folks I have seen run em dry all did it at a lot faster than idle speed.

Connelly · 06-12-2010, 02:39 PM

Quote:

Originally Posted by Flatfish

True. But the vast majority of folks I have seen run em dry all did it at a lot faster than idle speed.

Corrrect. Then they pull on the rope or contiune to crank the engine. Causing wear and premature falure.

Gundog · 06-12-2010, 06:38 PM

This is not OK with fuel injected motors.

feisty's wife · 06-15-2010, 07:34 AM

Great thread.

gpm414 · 06-17-2010, 06:57 AM

Before storing for the winter, I always disconnect the fuel line and drain the gas from the line and bulb.

ET · 06-17-2010, 12:32 PM

Quote:

Originally Posted by dsilvery

......I have ran my engine till it shuts off after every trip out. I have never had any issue with starting by doing this......

And in 12 years I've NEVER run my motors out of gas or ever used Stabil...and NEVER had an issue starting by doing this... I do use a fuel/water separator though and change the filter every year.

Seems like a lot of wasted time and fuel to run them out every time you go fishing....

A couple of caveats.... my boat is stored under cover... I usually don't go much over a month without using it...all year long..

ralf chumsalot · 06-17-2010, 09:24 PM

I will run my kicker out of fuel every time. I have yet to have any issues with it. Never run the injected motors out as it is bad for the injectors and fuel pumps.

ondarvr · 06-18-2010, 08:31 PM

Well, I haven't run my outboards out fuel in over forty years of boating and I don't have problems either. What does it prove?

Remember running it until it stops does NOT run the carbs dry, it only lowers the fuel level in the float bowl.

ralf chumsalot · 06-18-2010, 09:04 PM

Quote:

Originally Posted by ondarvr

Well, I haven't run my outboards out fuel in over forty years of boating and I don't have problems either. What does it prove?

Remember running it until it stops does NOT run the carbs dry, it only lowers the fuel level in the float bowl.

I do it mainly cause that's what my dad and grandfather have always done. It makes sense that there will still be fuel in the bowl. I guess that if we are truly die-hard fisherman our boats do not set long enough for this to even be an issue anyway.