Disconnecting the fuel line, let engine burn gas ?

[minnred]

I've heard pro and con about this question. Normally when I'm done fishing, and won't be using the boat for a week or so, when I come to the dock, I'll disconnect the fuel line and let the engine run until it stops. If I plan on fishing the next day, I'll leave it connected. Thoughts ??

 

[zippy83]

If this is a carbureted engine you will never get all the fuel burnt off, there will always be some left in the carb, I was told using Stabil on every fill-up will prevent issues with the carbs. I have had a two stroke carbureted engine for almost 8 years and stored it in my garage over winter(3-4mo), prior to storing I would fill it up all the way and would add the right amount of fuel stabilizer and never had issues.. (this was on a 1973 Mercury 50HP)

Now I got a new 2021 4 stroke Merc 200 Pro XS and I continue to add Stabil on every fill-up (1oz per 10Galons)

Hope this helps

 

[ThomW]

If you are only going a week or two between uses, there is not point in trying to empty the carbs of gas at the dock...a week or two isn't long enough to have any real issues arise from good gas sitting in the carb. Storing it for months at at time can be a different story, then you could consider draining the carbs of any gas...either by running it out, or by pulling the drain screw out of the carb bowl....

 

[minnred]

If you are only going a week or two between uses, there is not point in trying to empty the carbs of gas at the dock...a week or two isn't long enough to have any real issues arise from good gas sitting in the carb. Storing it for months at at time can be a different story, then you could consider draining the carbs of any gas...either by running it out, or by pulling the drain screw out of the carb bowl....

Thanks for the reply.

 

[minnred]

If this is a carbureted engine you will never get all the fuel burnt off, there will always be some left in the carb, I was told using Stabil on every fill-up will prevent issues with the carbs. I have had a two stroke carbureted engine for almost 8 years and stored it in my garage over winter(3-4mo), prior to storing I would fill it up all the way and would add the right amount of fuel stabilizer and never had issues.. (this was on a 1973 Mercury 50HP)

Now I got a new 2021 4 stroke Merc 200 Pro XS and I continue to add Stabil on every fill-up (1oz per 10Galons)

Hope this helps

This is a carbed 1996 Merc 60hp 2 stroke. I've never thought of using Stabil with each fill up. Interesting thought. I use it mainly for when I winterize my boat engine tanks. Thanks for the reply.

 

[Scott Danforth]

Use the boat every weekend and there is no need to do anything but key off and tilt up

 

[dingbat]

Years back, I removed the quick disconnect at the motor and let the motor run out of gas while I ran to get the truck.

Current motor is hard plumbed to the carburetor. Simply not feasible to remove and let run out of gas after each outing.

Concerned at first, but here we are 20 years later.......stabilize fuel in tank and let run to get stabilzed gas in the carbs before putting to bed in the winter. Top off with fresh gas in the Spring and go boating.

 

[JimS123]

Grandpa gave me my first outboard motor in 1965. He told me to run the gas out when I was done using kit. I've been doing that ever since, with no exception.

I have read that some of the very small 4-strokes with little carbs will eventually have problems if gas is left in. I have 3.5 and 5.0 Mercs and so far they start second pull every time. Someone told me that Mercury had a service bulletin that recommended the procedure.

Surely, pulling the plug will leave a little gas, but I find that if you work on the choke just as its running out it'll pull out a little more.

 

[flyingscott]

It depends on the 2 strk and the injection system. If your motor injects into the fuel line as a VRO or most Mercury carbed motors do, then I would not. Simply because the oil pump is still pumping so you fill the line up with oil. Older Yamaha, Suzuki systems inject behind the carbs so that is not an issue. I run BRP 2+4 fuel system stabilizer and nothing else.

 

[Chris1956]

Two cycle engines provide gasoline and oil to each cylinder. The concern is that if you disconnect the fuel supply to a multi carb, multi cylinder 2 cycle engine, some carbs will run out of fuel sooner, and the engine will continue to run without any oil to some cylinders.

Stabilize the fuel in the fall, run the engine to distribute the stabilized fuel, fog the engine, and turn her off. Let her drain, change the gear oil, grease the fittings and steering and store her away.

 

[airshot]

Two cycle engines provide gasoline and oil to each cylinder. The concern is that if you disconnect the fuel supply to a multi carb, multi cylinder 2 cycle engine, some carbs will run out of fuel sooner, and the engine will continue to run without any oil to some cylinders.

Stabilize the fuel in the fall, run the engine to distribute the stabilized fuel, fog the engine, and turn her off. Let her drain, change the gear oil, grease the fittings and steering and store her away.

That was how I was taught years back, many years back actually !! Single carb motors was ok to run out the fuel but never on multicarb engines. Back then we didnt have all these products to keep the fuel from going bad, so why not take advantage of science and use the products designed to help us.

 

[JimS123]

That was how I was taught years back, many years back actually !! Single carb motors was ok to run out the fuel but never on multicarb engines. Back then we didnt have all these products to keep the fuel from going bad, so why not take advantage of science and use the products designed to help us.

In all the years I ran triple carb motors I did the disconnect as well. If the pistons aren't already lubed with a lot of oil, then something else is wrong because a few seconds with no gas ain't gonna hurt it.

My 1955 Mercury outboard owner's manual says to use gas stabilizer during the off season, so Stabil is not a new concept.

Besides, the gas in the carb will evaporate gumming things up and THAT's part of the problem. Better to not leave much there in the first place.

It's so funny to me that common practice back in the 1950's is now poopooed.

 

[airshot]

Keep in mind we use far less oil in the gas today than in 1955 !! Also different types of bearings and materials. The aluminum we use today was not heard of in the 50's. Today's closer tolerances can be damaged more quickly and .....hopefully we have learned something over the years that can help us take better care of our stuff today !!!! In the 50's a woman stayed in bed for one full week after having a baby, but we have learned that causes serious medical issues down the road...

 

[flyingscott]

Two cycle engines provide gasoline and oil to each cylinder. The concern is that if you disconnect the fuel supply to a multi carb, multi cylinder 2 cycle engine, some carbs will run out of fuel sooner, and the engine will continue to run without any oil to some cylinders.

Stabilize the fuel in the fall, run the engine to distribute the stabilized fuel, fog the engine, and turn her off. Let her drain, change the gear oil, grease the fittings and steering and store her away.

That is an old wives tale. Here is why how many motors ran out of gas water skiing or any other activity?

 

[flyingscott]

Keep in mind we use far less oil in the gas today than in 1955 !! Also different types of bearings and materials. The aluminum we use today was not heard of in the 50's. Today's closer tolerances can be damaged more quickly and .....hopefully we have learned something over the years that can help us take better care of our stuff today !!!! In the 50's a woman stayed in bed for one full week after having a baby, but we have learned that causes serious medical issues down the road...

That is also an old wives tale. When Evinrude went to 50-1 in 1964 they did not re engineer the whole line. Just changed the oil. When they went to the E-tec, they used the existing 60 degree block.

 

[jimmbo]

It is still not a Wise Idea to let one carb dry out before rest of them

 

[Chris1956]

When Evinrude went to 50::1 gas-oil ration, it was because they converted their sleeve bearings to roller and needle bearings. Sleeve bearings need more oil in the mix to rotate properly.

By 1964 all Johnnyrude models had been converted.

 

[jimmbo]

When Evinrude went to 50::1 gas-oil ration, it was because they converted their sleeve bearings to roller and needle bearings. Sleeve bearings need more oil in the mix to rotate properly.

By 1964 all Johnnyrude models had been converted.

A lot of OMC Outboards were Needle, Roller, and Ball Bearing going back as far as 1957. Even after the switch to 50:1 in 1964, some of their smaller engines, the 5 1/2 for example, still had Sleeve Bearings for the Lower Crankshaft Bearing. I guess they figured there would still be enough pooled oil to keep it lubed. I know there were no differences in a lot of the 1964 engines compared with the 1963 Engines, except for a new Tin Plating on the Pistons, apparently for gentler Break In.

 

[Chris1956]

Yes, my 1958 Fat-Fifty was roller and ball bearing. I even found a piece of a clam shell in the lower main ball bearing. Didn't see to affect it though.

I think the smaller OBs were sleeve main bearing until 1963 or 1964. Not sure when the big twins changed over.

 

[jimmbo]

Our 57 35hp powerhead was full anti friction bearing