2 stroke shut off procedure - Page 2

psycho · 07 October 2015, 08:56

Could I ask, you say that you noticed the smell and presence of petrol only when you tilted the engine....

Could it be as simple as, and I and many others have done on many occasion, that you did not close the breather vent on the tank, allowing it seep out when in tilt position????

jeffstevens763@g · 07 October 2015, 09:10

i was always under the impression you ran dry and have done for years but i notice with some 2st garden engines you cant run dry but they do have primer bulbs may be they drain back to the tank.
on the old moped 2st if left for a while the petrol evaporated and left a white powder on the float chamber walls guessing that was corrosion from the water content in the petrol on the aluminium.
also modern day fuel doesn't last as long in some cases only three months so i stabilize
every tank.

AdrianTurner · 08 October 2015, 14:39

Quote:

Originally Posted by psycho

Could I ask, you say that you noticed the smell and presence of petrol only when you tilted the engine....

Could it be as simple as, and I and many others have done on many occasion, that you did not close the breather vent on the tank, allowing it seep out when in tilt position????

I'm sure it has happened many times but as a complete novice I'm a bit belt-n-bracers at the moment. First thing I checked when I saw the fuel was the vent and the filler cap itself.

Just run it again in test tank to run it dry but on turning off the fuel knob sod all happened!! the only way I could get it to run to a stop was to close the vent. Is it common for the fuel shut off valve to stick open even though the linckage seems to be functioning?

paddlers · 08 October 2015, 15:05

Hi, there's always a lot more fuel in the float chamber than you think especially if the engine's only ticking over. My Tohatsu 20hp 4 stroke takes ages but when I was at the dealers he simply unscrewed the drain plug and it's job done.
I always put a good squirt of fogging oil in each spark plug hole also when I'm putting it away for the winter.

AdrianTurner · 08 October 2015, 15:45

Quote:

Originally Posted by paddlers

always a lot more fuel in the float chamber than you think

Thanks Paddlers
It was still running after around 5 - 10 minutes, any idea how long I should expect it to run with fuel turned off?

paddlers · 08 October 2015, 16:10

No idea, sorry. Can you access the drain on the float chamber? I prefer this method anyway as I like to think that any crap will get flushed out with the fuel.

psycho · 08 October 2015, 16:55

Quote:

Originally Posted by AdrianTurner

Thanks Paddlers
It was still running after around 5 - 10 minutes, any idea how long I should expect it to run with fuel turned off?

That sounds about right. The smaller the engine, the less fuel they burn. My 10hp, 2/ will run for a good 3 or 4 minutes with fuel disconnected, on tick over.

jeffstevens763@g · 08 October 2015, 18:47

My Suzuki 25 4st runs for 15min

AdrianTurner · 08 October 2015, 23:11

thanks guys I'll give it another go tomorrow, and be more patient.

9D280 · 09 October 2015, 10:11

Also rememebr if your inbuilt tank / shut- off valve is anything like my decrepit Johnson 4 not only is there the carb bowl but the fuel filter and 6" of hose to empty as well! The Merc (60) takes a good 2-3 mins when on muffs

Depending on the size of the bucket etc, opening the throttle slightly speeds things up!

AdrianTurner · 09 October 2015, 19:10

This is now getting more than a tad frustrating. Run it with shut off valve off for over 30 mins, even in gear with a little throttle. Looking at how the fuel lines are connected I cannot see how the shut off valve could affect the flow, in the exploded diagram attached the integral fuel tank is connected to 33, there is a hose connecting the crankcase to 9. The hose connector adjacent to 9 has no hose. The fuel pump has a hose leading from the external tank connector and also a connector with no hose.

This arrangement makes no sense to me, I’m beginning to think that the previous owner had done some work on it and got a bit lost when putting it back together. Unfortunately I’ve not been unable to find a definitive schematic of the correct fuel line arrangements. Hopefully someone here will know what it should look like.

paintman · 09 October 2015, 19:54

If there is a fuel shut off valve between the carb & the fuel supply & it's fully closed but the engine continues to run as yours is then it's either defective or there's another operational fuel line that you haven't found.
Trace the fuel lines from the carb to their other ends.

It is a shut off valve not a changeover valve from internal to external tank?
My Suzuki 4hp has this type of valve. When it's in the external position without an external tank connected it quickly dies. I use it to shut the fuel off when it's tilted up or not in use.

AdrianTurner · 09 October 2015, 20:40

Just found a video on Youtube which clearly shows that the integral tank hose should be connected to the connector adjacent to 9 in the diagram (no hose at present) and a hose from the unused connector on the pump to 33 in the diagram (where the integral tank is connected know). So my suspicions seem to be correct, the previous owner has lost his way when putting things back together.

Thanks all for your help and suggestions.

C-NUMB · 09 October 2015, 20:49

I believe in running it dry as Xk59D recomends. This in connection to use the spare connector (on the engine) while running the engine out of fuel and spraying fogging oil into the carbs. Just stripped the carbs on my Yam 90 aeto. There was absolutely no varnish in any part of the carbs. There was som crap in the bowl of lowest carburator, but as always used a 10 micron main filter, think that has been there before "my time".