Old petrol - starting and running problems

[William_H]

I think the problems must be related to the additives in fuel in UK. I have never seen this effect in Oz . Fuel is carried over from season to season. re complaints about UK winter hanging around with snow. Funny we are getting similar effect here in West Oz (Perth) had an all time record high temp for April yesterday of 36 degrees max. With now about a week of over 30s. It is supposed to be getting colder and raining by now. has the earth's tilt cycle slowed down? No sun is setting earlier now. Got to go scrub the boat again. It is nice in the water olewill

 

[jwilson]

Another possible cause of the problem is the hygroscopic nature of modern alcohol containing petrol. When old fuel, which may have absorbed some water, evaporates over a winter layup the water may be left behind at the bottom of the float chamber. When you try to start it is that water which is sucked in first and prevents starting.

I was told this years ago by an outboard engineer when leaded petrol - containing no alcohol - was still available. His advice was to use leaded in outboards. This transformed the starting of my outboard.

It's a very long time I think since real leaded was available, but when it was it was it always regarded as bad for two-stroke use, as it caused whiskering on the plugs, which used to be a very common reason for two-strokes, from motorcycles to outboards, stopping running. The advice then was because expensive high-octane petrol contained more lead, to run two-strokes on the cheapest petrol available to get as little lead as possible.

Last year my small 3.3 two-stroke outboard started second pull (as usual) in March 2012 on fuel that had been in it's plastic tank since September 2011. I had however taken the carb off and cleaned it first, and removed the (6 year old) spark plug, looked at it, and put it back as it looked OK. I think bad starting on small outboards is almost always dirty carbs, not old fuel.

Haven't done this yet for 2013 though, was due to launch two weeks ago but delayed it......

An afterthought - I have in the cellar a 3.3 Mariner two-stroke that has had two hours running from new in around 2009 - I bought it to have a spare two-stroke for when the in-use 3.3 eventually dies. It has in it's tank maybe a pint of some 2009 petrol. If I have time, I will clean the carb and then see if it starts OK on the 2009 petrol.

 

[Robert Wilson]

An afterthought - I have in the cellar a 3.3 Mariner two-stroke that has had two hours running from new in around 2009 - I bought it to have a spare two-stroke for when the in-use 3.3 eventually dies. It has in it's tank maybe a pint of some 2009 petrol. If I have time, I will clean the carb and then see if it starts OK on the 2009 petrol.

Some people are in such a rush, these days. We'll expect your timely report around about 2017 then!!

 

[vyv_cox]

I have to say that these tales of petrol going off surprise me, as my experience is very different. My outboard in Greece is always laid up for the winter anyway, but is used very infrequently as we mostly row. Consequently the fuel, bought 5 litres at a time, lasts for years but has never given starting problems.

At home I have a strimmer that ran well on 7 year old petrol when we returned home from working abroad. My Clarke generator is used very infrequently and has had the same tank of petrol for at least three years, maybe five. I used my chainsaw a couple of weeks ago, it started easily on fuel that has to be more than two years old.

 

[nigelmercier]

I have to say that these tales of petrol going off surprise me...

Me as well, until I had a chainsaw that would not start. Changed the petrol, refilled, primed, started first time. From then on if a petrol device didn't start, I did the same, always fixed it. Then I discovered the additive in Post #20. Never needed to change fuel since.

 

[chewi]

If the mix of petrols has been changing in recent years could it be that those who successfully use old fuel use so little of it that an old fuel formulation is still good, but those who use more recent fuel find it less enduring?

I have had problems with a Honda 2.3 where any water that presumably condenses in the cans arrives at the carb bowl which being mild steel , corrodes both the bowl and the drain screw, then delivers corrosion products to the jet. Am not a at all impressed with the amount of mild steel in the Honda engine, their bikes were better than this engine.

 

[davidpbo]

Can the additive re-rejuvenate old petrol?

I always run my outboards out of fuel, but last year did not use my tender OB other than in the OB tank for a while.

Went to say hello to my mooring last weekend and OB would not start, also only had 1.5 oars but that is another story.
Took the float chamber off and wish I had taken a picture of it it had that much crud in it, almost like foam.

Due to not using much last year I have several cans of fuel some from the year before, I intend to filter it and mix with new and wonder whether the additive would improve it.

 

[Stemar]

I wonder if the problems with old fuel aren't more to do with gummed up jets & float chambers. I always run my Tohatsu 3.5 in fresh water to rinse the salt out, starting it, then turning the fuel off and waiting until it stops before putting it away.

It got that treatment last October and wasn't touched until last week, when it started and ran fine on the fuel that had spent the winter in the tank. (I had planned on spoiling it a bit with some nice new mix, but that was on the boat, out in the harbour...)

 

[vyv_cox]

I wonder if the problems with old fuel aren't more to do with gummed up jets & float chambers. I always run my Tohatsu 3.5 in fresh water to rinse the salt out, starting it, then turning the fuel off and waiting until it stops before putting it away.

It got that treatment last October and wasn't touched until last week, when it started and ran fine on the fuel that had spent the winter in the tank. (I had planned on spoiling it a bit with some nice new mix, but that was on the boat, out in the harbour...)

I think you are probably right. I run all my petrol-powered equipment dry every time I use them.

 

[ChrisE]

I have to say that these tales of petrol going off surprise me, as my experience is very different. My outboard in Greece is always laid up for the winter anyway, but is used very infrequently as we mostly row. Consequently the fuel, bought 5 litres at a time, lasts for years but has never given starting problems.

At home I have a strimmer that ran well on 7 year old petrol when we returned home from working abroad. My Clarke generator is used very infrequently and has had the same tank of petrol for at least three years, maybe five. I used my chainsaw a couple of weeks ago, it started easily on fuel that has to be more than two years old.

I have the same experience, I've just started a four stroke outboard that hadn't been used for 3 years and a couple or three pulls it fired and not for the first time either. My outboards are left untouched and unloved each close season for 4-6 months and start with the same fuel that's been sitting in the tank.

Perhaps, it is the way that they are started? I always give them choke and pull the starting handle 3 or 4 times then pull it until I can feel compression then 1-3 strokes later off they go. On the odd occasion that this doesn't work, knock off the choke and open throttle right up and give a few more pulls from a compression position.

 

[davidpbo]

I wonder if the problems with old fuel aren't more to do with gummed up jets & float chambers. I always run my Tohatsu 3.5 in fresh water to rinse the salt out, starting it, then turning the fuel off and waiting until it stops before putting it away.

It got that treatment last October and wasn't touched until last week, when it started and ran fine on the fuel that had spent the winter in the tank. (I had planned on spoiling it a bit with some nice new mix, but that was on the boat, out in the harbour...)

My outboard is used almost exclusively in fresh water and as far as I recall always run dry, I don't remember when I last checked the float chamber so have no idea how long the crud had been there.

 

[razo]

It's never a good idea to run a 2 stroke dry to drain the carb.Your starving the motor of oil.Even for a short period,not a good idea.....

 

[Lakesailor]

Further to my earlier thread about my two outboards (4HP 2strk & 2.3HP 4strk) which would run only with chokes out and were "pigs" to start.
After faffing about with plugs, carbs, linkages etc etc., in final resignation I changed the petrol yesterday.
BINGO!!

I bought the petrol three months ago, stored it in the usual plastic can, in the yard. I'm amazed it deteriorated so quickly.
Usually I've kept petrol for up to a year without problems. Has the chemical make-up of petrol recently been changed?

Lesson learnt.

If Nigel was still on these forums (he was a fuel blender) he would tell you it's the daylight that causes fuel to go off. If you are storing it outside put it in a steel can that is opaque. I keep my fuel in a dark garage and all my motors start, not problem, after a year off (leaf blower, hedge trimmer, lawnmower and outboards)

It's never a good idea to run a 2 stroke dry to drain the carb.Your starving the motor of oil.Even for a short period,not a good idea.....

Can't see that at all. The engine stops when there is no fuel. The oil does stick to the bearings.

 

[Robert Wilson]

If Nigel was still on these forums (he was a fuel blender) he would tell you it's the daylight that causes fuel to go off. If you are storing it outside put it in a steel can that is opaque. I keep my fuel in a dark garage and all my motors start, not problem, after a year off (leaf blower, hedge trimmer, lawnmower and outboards)
QUOTE]

Dear Sir,
Thank you for your communication of the 10th inst., in which I notice you offer advice regarding the problems of using sub-standard petrol.
In your communication you state that storing petrol in plastic cans can allow light to have a detrimental effect on the properties of the propulsion liquid.

I gratefully accept your advice as to the reasons why my outboards performed to a standard far below to that which I have previously experienced; and expect thereof.

BINGO !!!

I have the pleasure to remain,
Yours faithfully,

R. A. W. Wilson

Post Script. Left the ****ing cans in full sunlight since December......................

 

[VicS]

It's never a good idea to run a 2 stroke dry to drain the carb.Your starving the motor of oil.Even for a short period,not a good idea.....

Small motors no problem... generally over oiled at low revs anyway... and you only run them dry at low revs so plenty of oil about.

there is apparently a problem with big multiple carburetor engines. The layout of the fuel system tends to result in the upper carbs running dry first but the motor keeps going driven by the lower cylinders ....... ie running the upper cylinders for a short time with no fuel and therefore no lubrication.