Running a 2-stroke outboard dry before storing ?

RichardS said:
The BP document says that modern engines will normally adjust themselves to run on alcohol / petrol mixtures. I'm not sure why that contradicts what Triassic was saying. :confused:

Richard
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And that is the nub of the problem. An outboard with a carburettor can hardly be called a modern engine. Particularly when made years before petrol was altered with bio products.
 
I recently did two carb jobs, motorcycle not outboard, and in each case they had not been drained before storage.On one job(R6) the floatbowls were all stained an emerald green.On the other(Buell) i ran off about a pint of emerald green liquid from the tank through the carb drain before the liquid started to run the normal petrol colour.After cleaning the Buell carb the engine started and ran on the fuel from the tank which to my certain knowledge is eight years old .
Can anyone tell me what the green(very strong smelling) liquid might be?Does ethanol separate from petrol after a long time in storage?Is it bright emerald green/tourquise in colour?Heavier than petrol?
Outboard wise I stop my 8HP Johnson with the choke so that there is always a lot of petroil in the crankcase/cylinder when laid up between useage.95% of the time it starts by the fourth pull from cold/being left for a week.The engine stays on tilt on the bracket when not in use.
Cheers
 
RichardS said:
The BP document says that modern engines will normally adjust themselves to run on alcohol / petrol mixtures. I'm not sure why that contradicts what Triassic was saying. :confused:

Richard
Click to expand...
EFI engines will generally adjust to run stoch and maybe push the timing to the point of knocking.
Carburettor engines used to low octane unleaded will run as they did, those set up for premium may run slightly richer, but the difference is tiny compared to the errors in carburation anyway.

But all that is out of the window if the fuel is saturated with water AIUI.
Probably also if the fuel is old and has been exposed to air too much. But that's never been a good idea.
 
I think we are looking at two topics here, one being do we need to avoid fuel with ethanol added because of the way it makes our engine run, the second being does ethanol harm out engines or make any difference to the way we lay them up.

With regard to the first I don't think our outboards are running to such critical margins that it's going to make a lot of difference, especially with a two stroke. I referenced to the TR article because we were talking about air/fuel mixture ratios and I thought the way they explained it didn't need a chemistry degree, but they are more concerned with how ethanol fuels can combust hotter which causes them issues with their non-electronic ignitions/carburettors/old valve seats which again won't impact on us.

The second issue, and the main one for me, is the potential destructive nature of ethanol added fuels and I thought the TR article explained that very well.

With regard to the BP article this is not about how modern engines can adjust to the fuel they are being fed. I am fortunate enough to also have a home in Brazil and there the vast majority of newer cars will run on both the alcohol or petrol readily available at the pumps, or any ratio of either depending on whatever took your fancy at the time. It is quite amusing watching friends who come to visit trying to get their head around the fact that alcohol and driving do mix......


edit: here's a link to the TR article if you are interested.

http://www.groups.tr-register.co.uk/wessex/ethanol-update.html
 
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third engines said:
Yes, and beware of squirting snake oil down carbs as our local "Marine Engineer " (said in the loosest possible terms). While performing the said proceedure in the flush tank at the local sailing club in an attempt to impress bystanders managed to provide an unusual noise and immediate cessation of rotation. Result bent connecting rod!!
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Years ago a friend owned a Mini that was rather tired. He hit upon the bright idea of punching a hole in the air filter, pushing a length of tubing into it and the other end inside the car alongside the speedometer. At times when he needed more power for overtaking he would squirt Easistart into the tube, which had the desired effect. As time went by he squirted more and more, with the inevitable result that the engine blew up in a most impressive way, con rods out of the crankcase, bent valves, smashed pistons and cylinder head.
 
Don't shoot the messenger, I only copied the article across...... Mind you, that is a bit of a schoolboy error on the authors part!
 
caiman said:
I recently did two carb jobs, motorcycle not outboard, and in each case they had not been drained before storage.On one job(R6) the floatbowls were all stained an emerald green.On the other(Buell) i ran off about a pint of emerald green liquid from the tank through the carb drain before the liquid started to run the normal petrol colour.After cleaning the Buell carb the engine started and ran on the fuel from the tank which to my certain knowledge is eight years old .
Can anyone tell me what the green(very strong smelling) liquid might be?Does ethanol separate from petrol after a long time in storage?Is it bright emerald green/tourquise in colour?Heavier than petrol?
Outboard wise I stop my 8HP Johnson with the choke so that there is always a lot of petroil in the crankcase/cylinder when laid up between useage.95% of the time it starts by the fourth pull from cold/being left for a week.The engine stays on tilt on the bracket when not in use.
Cheers
Click to expand...

Iron sulphate heptahydrate is a very common form of corrosion product that is emerald green. I suspect that you are seeing the result of corrosion of the steel (I assume)
tank by some water in the fuel. Water will have a greater affinity for ethanol than it will for gasoline, which may perhaps lead to separation but the chemistry is beyond me. Maybe VicS has some thoughts?

A colleague of mine did quite a lot of work on the corrosion of aluminium manifolds before Shell introduced ethanol in its fuels. I believe that the composition of the alloys used was changed as a result, so dating from around 1990 onwards.
 
Although the R6 tank is steel,(I inherited the job after the tank was removed/drained)the Buell tank is a form of 'plastic'.The only iron/steel based items in the Buell fuel system are the spindle for the float and the needle.When I drained the carb,due to the amount of 'green liquid' emerging I switched to draining directly from the tank so that(unfortunatly) would rule out your theory. The liquid has the 'traditional' pungent stale petrol smell,but like the 'varnish'/'gum' is the bright green colour.The jets had gone black on both bikes.
The Buell has a Harley engine and dates from 1998 so that should rule out the ally possibility but thanks for the info.
Both bikes are now running OK(s/h carbs for the R6,clean out for the Buell) but I would be interested in any other theories/ideas.
Thanks again for your input.
Cheers
 
'black jets' suggests reaction by sulphur, also needed for the iron sulphate. Maybe contaminated fuel from steel storage tanks? Cannot think of an explanation as to why hydrocarbons would go green without some inorganic content.
 
caiman said:
Although the R6 tank is steel,(I inherited the job after the tank was removed/drained)the Buell tank is a form of 'plastic'.The only iron/steel based items in the Buell fuel system are the spindle for the float and the needle.When I drained the carb,due to the amount of 'green liquid' emerging I switched to draining directly from the tank so that(unfortunatly) would rule out your theory. The liquid has the 'traditional' pungent stale petrol smell,but like the 'varnish'/'gum' is the bright green colour.The jets had gone black on both bikes.
The Buell has a Harley engine and dates from 1998 so that should rule out the ally possibility but thanks for the info.
Both bikes are now running OK(s/h carbs for the R6,clean out for the Buell) but I would be interested in any other theories/ideas.
Thanks again for your input.
Cheers
Click to expand...
I wonder if somebody has added something to the fuel?
Were they from the same place?
I once bought a couple of non-running Benelli two strokes, had a terrible job cleaning the tanks and carbs, didn't suss it until I found recogniseable white sugar.
This before the days of locking fuel caps being common on smaller bikes.

As well as ethanol, all sorts of other things are routinely added to pump fuel.
Particularly the extra-cost fuels from Shell and BP.
It's possible the dosing of additives went wrong?
 
I see a lot of "Green" fuel coming from engines that have been laid up. If you leave that green fuel longer it turns brown and you can smell it from a thousand yards. Fuel that is a few weeks old that has been exposed to air also has a green tinge to it
lw395 said:
I wonder if somebody has added something to the fuel?
Were they from the same place?
I once bought a couple of non-running Benelli two strokes, had a terrible job cleaning the tanks and carbs, didn't suss it until I found recogniseable white sugar.
This before the days of locking fuel caps being common on smaller bikes.

As well as ethanol, all sorts of other things are routinely added to pump fuel.
Particularly the extra-cost fuels from Shell and BP.
It's possible the dosing of additives went wrong?
Click to expand...
 
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