2 stroke shut off procedure

AdrianTurner · 06 October 2015, 12:24

As a total newbie I’ve been trawling this forum and googling to find the proper shut down procedure for a 2 stroke but have found conflicting information. I have been prompted to look into after I ran the outboard (Johnson 4hp MY2000) in a test tank for around 15 mins, I lifted (tilted) the shaft to its highest point and left it for a few minutes. After removing the test tank I dropped the shaft back to normal, there was a strong smell of fuel and on inspection I found fuel dripping from the case. After removing the lower case and wiping up the leaked fuel, I could not find an obvious source but the carb throat was very wet. Would I be correct in thinking that the fuel in the float chamber could seep through and then out of the carb throat?
I had shut off by pulling the kill-switch cord and shutting of the fuel, is this the correct procedure or should the fuel be turned off and engine run until the fuel in carb has been used?

Xk59D · 06 October 2015, 12:46

i always store my 2 strokes dry.

i.e run the fuel out them completely and store, if for a long time a wee bit of fogging oil down the plug hole too.

the fuel from the carb could be you tilted it too far or stuck float or just residual fuel in the carb that wasn't burnt off.

shut off during normal use there is sometimes a button on the engine (usually where the kill cord goes in you push that to kill it). failing that just pull the kill cord.

HTH

Poly · 06 October 2015, 13:05

Many years ago I used to stop sailing club engines by disconnecting the fuel supply and running ashore just on the remaining fuel in the carb. There was a skill in judging it so you arrived at the shore just as the engine cut out. Those engines lasted well with that approach each week, but there is a school of thought that for a premix two stroke you are running the engine lean and thus oiling it less before stopping which could be bad.

Its generally agreed that leaving fuel in carbs (especially premix) is not a good idea for long. periods. However I don't think a leak is expected from tilting, although perhaps not uncommon.

9D280 · 06 October 2015, 13:22

+1 on Poly et al rnning dry.

One importany point - is it premix or is there an oil tank on the engine?
- Premix if you donlt run it dry the TCW3 will likely end up blocking your idle jets etc.
- as for running lean the other trick is as it starts to make different noises, pul lthe choke. not only does it richen the mixture but it also gets a bit more fuel out the carb!

My personal view is that there is going to be more than enough residual oil in the crankcase to let t turn for the 10 or so revs it wil llast at that moment, especially as it's at idle therefore running cooler. (remember an automixer wil likely be oiling at 200ish:1 at that speed, so a lean premix 50:1 won't be an issue

Now, as for leaky carbs...... the fundamental flaw with some carbhs is the inlet valve float is hinged in the wrong place. As the engine tilts you want that valve to kee pthe inlet shut (a bit like a hamster drinking bottle - the water stays in by the vacuum at the top). If, like my Clamshell, the valve natrally falls open by gravity......

For me it's a run dry every time. - Usually on the muffs as I'll be flushing it.

AdrianTurner · 06 October 2015, 13:58

Quote:

Originally Posted by 9D280

One importany point - is it premix or is there an oil tank on the engine?

It is premix, would it be OK to burn of residual fuel by running with fuel turned off?

I've just had it out (after two weeks stood up in the shed) on a stand and without running it I titted it to its max position and left it for 30 mins or so, NO leaking fuel

So I assume it was just the residual fuel that had leaked previously. It will be used on a 2.7m SIB which be be rolled up and transported in the car boot along with the outboard. My corcern is not getting any residual fuel leaking into car boot. What do others do in this situation?

Xk59D · 06 October 2015, 15:08

run the engine dry before putting it in the car...job done.

AdrianTurner · 06 October 2015, 15:10

Quote:

Originally Posted by Xk59D

run the engine dry before putting it in the car...job done.

That would be my solution too, put wanted to check as I've seen some posts that say never run a 2 stroke dry.

Thanks

Fenlander · 06 October 2015, 15:15

>>>some posts that say never run a 2 stroke dry

I may be one of those.

My usual experience 2hp-25hp is... I stop the engine at idle and remove the fuel line or switch the fuel off at the tap if an integral tank. Never had a problem with them leaking in the car or being a problem to start... even after 14mths standing.

Not saying others that run dry are wrong...just I've never felt the need.

AdrianTurner · 06 October 2015, 15:51

Quote:

Originally Posted by Fenlander

I may be one of those.

Really! LOL

Thanks Fenlander.

Seems there are definately two camps of opinion on this. I guess the safest option would be to put an impervious sheet in the boot and try it without running until dry.

Xk59D · 06 October 2015, 16:23

there are indeed 2 camps, those than run it dry and those that SHOULD run it dry

you are giving yourself more potential problems not doing so IMO. moisture attracted to bores, petrol smell, petrol spills, varnish build up, those largely go away running it dry.

Fenlander · 06 October 2015, 16:26

Duplicate post - sorry.

Fenlander · 06 October 2015, 16:27

Despite not suffering problems I always put a plastic tarp in the estate loadspace area before I go sibbing as my carpet is a delicate (?) shade of light grey. I also put the outboard on an old blanket so should it leak fuel or water it will be absorbed not trickle away somewhere.

I'm a just in case type of guy!

And don't misunderstand... I have no view that running dry is a problem... just never been my habit.

slate1234 · 06 October 2015, 17:09

if useing an external fule tank use a spare fuel connector (on the engine) saves and damaging the fuel pum diaphragm.

slate1234 · 06 October 2015, 18:20

That made no sense at all sorry, use the spare connector (on the engine) while running the engine out of fuel

AdrianTurner · 06 October 2015, 19:13

Quote:

Originally Posted by slate1234

That made no sense at all sorry, use the spare connector (on the engine) while running the engine out of fuel

Integral tank on this one.

Thanks for all the advice guys, it seems that there is no right or wrong way with this situation, just a matter of preference.

Landlockedpirate · 06 October 2015, 21:55

Nope, there is a right and a wrong way.

Turn the fuel off and let the engine run till its all gone. As Xk59D says, leaving fuel in the carb will eventually gum it up over time with oil.

Fenlander · 06 October 2015, 22:21

>>> will eventually gum it up over time with oil.

That has to be a "might in some/extreme circumstances" not "will"... or none of my outboards would ever have restarted over decades of smallcraft boating??

Xk59D · 06 October 2015, 23:00

varnish up doesn't mean your engine won't start, nor does the extra corrosion potential leaving fuel in the cylinders mean it won't start, heck it may not even make one iota of difference to your engine/s......but it does increase the chance of it. the varnish will burn off in the next heat cycle if it does start.

i can say 99% i have lost an engine due to not running it out of fuel. it was a suzuki 85hp 1990 ish model many years ago. i never used to run them dry but i started to notice performance degrading over time and eventually one cylinder lost a lot of compression. when the outboard shop put their mirror thing down the plug (this is long before the fancy digital ones) you could see where fuel and hence moisture had gathered at the bottom and subsequently rusted the ring we assumed.

the engine was a write off but i pulled the head on it anyway, you could certainly see evidence that the above was the probable cause and on the shops recommendation i have since never done it.

back then the oils were not as good which may not have helped my cause but the fact is fuel attracts moisture so why risk it?

TBH, i can't think of a reason NOT to run dry, i'm sure someone may have one but i can't think of one ATM?

edit- potential reason not to do it....seals will dry up, would probably happen anyway so maybe not a huge factor??. this is why i never winterise engines personally, i just run them every couple of weeks.

Nightfisher · 07 October 2015, 07:35

Owning a few Mercs in my day, I have never had a problem starting the following year by, as some above suggest, pulling the fuel line while running (for any length of storage time) and allowing the engine to shut-down through fuel starvation. For longer periods, say 4 months or more, I also concur with others above, fog the engine through the carb while running (this will lubricate bearing and needle bearings inside); and squirt a few drops of good two-stroke oil (if it's two-stroke) in the cylinder(s) after removing the plugs and high-tension wires way out of the way to prevent shock - cranking a few times before reinstalling the plugs/HT Wires.

If you have carb leakage install a new carb gasket kit (including fuel pump diaphram if that power level has one(don't put in the pump valves backwards)). Check and adjust float level. It's all fairly simple stuff. Good Luck.

Searider · 07 October 2015, 08:54

When I was a teenager we had a selection of 2hp and 4hp 2 stroke engines. We always ran the fuel out of them as they were going to be stowed in the enclosed bilge of another boat.
Never had any problems.
The 20hp and 50hp 2 strokes (premix) I had later I always ran the fuel out and never had any problems.
The 90hp and 30hp automix engines I've had more recently I just turn off at the key and also haven't had any problems.