Does running a 15hp 2 stroke out of gas cause pre mature wear or damage?

[Slamaha57]

Hi,

I own a 2009 15hp 2 stroke Yamaha outboard. It has been excellent thus far and I've had no problems with it.

I run it with OPTI 2 Stroke Syntheic Oil premixed at 100:1.

I transport my boat in the back of my truck and take the outboard off of the boat everytime I use it.

Per the advice of my Uncle (a heavy duty mechanic) and an older boat mechanic I knew, I have always been in the habit of unplugging the fuel line from the motor at the boat launch to run the carbs dry. The reasons for doing this are prevent the gas from spoiling or evaporating and gumming up the carbs between usages, and to prevent fuel from leaking out into the water or the boat when I take outboard off of the boat.

I usually unplug the line 20 yards from shore, run up beside the launch, shift to neutral, and let the unit idle (leg in the water) until runs out of gas while I fetch the truck.

I was told today, by a mechanic, that running the carbs dry like that is not good for the motor and could cause premature wear/damage as, "there is no oil to lubricate the rings as the pistons fly around after fuel runs out".

This doesn't make sense to me as I would think that the pistons stop after the fuel runs out because there is no combustion to provide the force required to force them down and up again to overcome the resistance of compression.

But I am not an expert, so I thought I would ask you folks and get your opinion.

Does running a 15hp 2 stroke out of gas cause pre mature wear or damage?

Thanks and regards,

Slam

[rodbolt17]

wont hurt anything.
however synthetic oils and 100/1 will.

but why bother, you simply cannot run the carb dry, no way no how,

however there is a drain screw that will drain the carb.

[99yam40]

Not sure how many carbs your motor has, but Motors with multiple carbs, usually the upper carbs run out of fuel sooner that the lower ones and so there will be some cylinders running very lean on fuel and oil.
I do not like the idea of trying to run a motor out of fuel.
Just an opinion

[BQUICK]

All fine IF you fog it when it's just about to die. Otherwise you are running the motor out of oil. You are already running 100-1 lean oil ratio so not much oil in the first place. In the days of 50-1 or 25-1 it was as not as much of an issue and may be why some "oldtimers" swear by it. Might be OK if it will be run withing a couple weeks but if it sits longer there is very little protection in there.

I'd like to see a test (take motor apart and examine) where 100-1 is run out vs. not vs. fogged after sitting in a damp environment with condensation for 6 months.

[Slamaha57]

All fine IF you fog it when it's just about to die. Otherwise you are running the motor out of oil. You are already running 100-1 lean oil ratio so not much oil in the first place. In the days of 50-1 or 25-1 it was as not as much of an issue and may be why some "oldtimers" swear by it. Might be OK if it will be run withing a couple weeks but if it sits longer there is very little protection in there.

I'd like to see a test (take motor apart and examine) where 100-1 is run out vs. not vs. fogged after sitting in a damp environment with condensation for 6 months.

Hey BQUICK,

You bring up an interesting point about examining a motor that isn't fogged after six months. I just found the owners manual and it states that if fogging oil isn't available and the motor isn't to be run for 2 months, to run it until the fuel system is dry. But I am sure that if it was to be stored longer than 2 months it should be fogged. But I am in Calgary and its pretty dry here, not sure we would qualify for damp conditions, the garage where the motor stays is below freezing most of the winter.

[Slamaha57]

wont hurt anything.
however synthetic oils and 100/1 will.

but why bother, you simply cannot run the carb dry, no way no how,

however there is a drain screw that will drain the carb.

Hi Rodbolt,

I was under the impression that synthetic oils were better than mineral oils for premix applications, I guess that may have been from the synthetic guys' (OPTI and AMSOIL's) add campaigns.

What are the pit falls of using synthetic over mineral oils?

[BQUICK]

Hey BQUICK,

You bring up an interesting point about examining a motor that isn't fogged after six months. I just found the owners manual and it states that if fogging oil isn't available and the motor isn't to be run for 2 months, to run it until the fuel system is dry. But I am sure that if it was to be stored longer than 2 months it should be fogged. But I am in Calgary and its pretty dry here, not sure we would qualify for damp conditions, the garage where the motor stays is below freezing most of the winter.

The oil injection motors run as little as 200-1 at idle so Yamaha says to disconnect the oil pump link and run it that way when shutting down for extended period.
Also, Yamaha and other manufacturers put out service bulletins saying to not run 100-1 in many cases. Dealers were advised to write "use 50-1 mix" on all owners manuals.
Personally, I just make sure the fuel is treated and I don't run the carbs dry unless it's going to sit for months.

[rodbolt17]

somer of the synthetics dont have the rust inhibitors that TCW III oils have.
you simply cannot run a carb dry, cant happen,wont happen.
they do however mostly have drain screws.

100/1 is fine if reccomended.
HOWEVER, at 100/1 it is assumed that any prolonged storage(over 30 days) and the engine is PROPERLY set up for long term(over 30 days) storage AND that the fuel and cooling system are maintained at peak condition.
that means no 5 year old cooling system parts and nbo 2 year old gas.

but ya'll doums as ye wishes.
I just fix them when they get broked.