Ethanol in petrol

[Matthew P]

Good advice Peter to fill petrol on filling - I've just had my Tohatsu 6HP serviced by Keith Fairbrother (Chester) and he found corrosion in the carburetor caused by water in the petrol. The corrosion was so bad that Keith fitted a new carburetor. Ouch. Last summer the carburetor filled with jelly within months of servicing - same problem - water in the petrol. I use an external tank which Keith says are vulnerable to water ingress - he recommends emptying all petrol and wiping it out internally to make sure no water is left.  For the amount of motoring I'll do I will just use the internal tank but be careful if I have to top it up when running and its hot... 

I'm also giving Aspen petrol a trial, as recommended by Graham, which can be found at: http://www.aspenfuel.co.uk/products/environmental-fuels/aspen-alkylate-petrol/aspen-4-alkylate-petrol/ Not cheap at £20/5 litres and hassle to locate, until you cost lost time and fury when the outboard won't start.

Matthew
BR20 Gladys

[Andy Dingle]

[quote I use an external tank which Keith says are vulnerable to water ingress -
[/quote]

Matthew. Thanks for sharing your painful experiences .. new carb sounds pretty drastic.

I was very interested in your comment re external tanks vs internal. I've just had my Mercury 6 serviced too. (Same engine, my chap says the only difference is that if the Tohatsu needs warranty work the importers will always challenge it, whereas with the Merc they will authorise the work straight away to save the 'good' name of the Mercs!!).

I can't recall your set up on Gladys but most people I think keep their external tanks in one of the side lockers out of the way and in the dry. I do on my 23. As far as I can see the only way water could get in, unless of course it's already in the petrol, is through the breather release in the tank cap - if it's in a locker and the tank sealed down after use each time then I would have thought that was unlikely, whereas the breather on the internal tank is subject to rain and spray ingress..?

As I said in an earlier post I spoke with my mechanic about Aspen - basically he said don't waste your money, just make sure you use fresh fuel - just get smaller amounts of fresh fuel each time, a lot cheaper than buying special fuels - as I use quite a bit of fuel I think that is probably my best option.
He didn't think much of additives either, but said I could try 'quickare' which is a Mercury Quicksilver fuel additive, which I will try as they can't then dispute the warranty if it all goes belly up.

So all in all I'm still confused as to whats best ... I dare say this conversation will run and run .. (unlike some of our outboards..!)..

Cheers

Andy

[Peter Taylor]

I was very interested in your comment re external tanks vs internal. ... As far as I can see the only way water could get in, unless of course it's already in the petrol, is through the breather release in the tank cap

So you take the boat out on a nice warm day and the wind drops and you motor back. While motoring the breather is open to allow air in to replace the petrol you use up. Warm marine air contains water vapour (order 10g/kg). You pack the boat away and close the breather. It's a cold night and water condenses from the air onto the insides of the tank and runs down into the petrol. Even without condensation the alcohol in the petrol is hygroscopic and can absorb water vapour from the air in the tank.

Not much water on each trip but for lazy people like me who simply keep topping up the petrol tank, then the water could collect in it. I assume that an exterior tank is likely to be more of a problem because there is more air space and it is rarely if ever emptied (at least mine isn't). One can imagine water collecting at the bottom of the tank only to go into suspension when you are out on a rough day.

I actually read my Tohatsu manual the other day (!RTFM - shock, horror!) and it mentions having a water excluding filter in the fuel line from the petrol tank. A Tohatsu Unikas UF-10K Outboard Fuel / Water Separator Filter costs about £70 bought from the USA on ebay. Force 4 has a different filter unit for £40 + cost of fittings to connect in fuel line and to fasten it so it and the fuel tank can still be removed to fill.  I think I'll investigate!

Peter

p.s. the guy who services my outboard doesn't think additives are needed and thinks I'm worrying too much about fuel problems. However his main business is servicing RIBs and their outboards, and I can quite believe that outboards on  RIBs don't have the problems which outboards on sailing boats experience!

[Andy Dingle]

Sound words of wisdom as always Peter..  Yes. You are quite right of course and I see how that would introduce water into the tank..
A separation filter would I think be wise. After all diesel engines on yachts use one - glass ones so the collected water can be easily be seen and drawn off when necessary...

Maybe your servicing guy is right that we are worrying too much - The chap who does mine too doesn't seem bothered at all by fuel - as long as it's fresh. I know loads of other fishermen, sports motor boat owners, jet skiiers, sailors and all sorts who use outboards daily and none seem to fuss about this as much as I do - at least the bar empties when I start to mention it..!
 
And none of this answers the question of why my lawn mower - that I fill with last years ob fuel, never gets even an oil change just keeps on going - started second pull this year with fuel in it that I left in from last year....

[Graham W]

I know loads of other fishermen, sports motor boat owners, jet skiiers, sailors and all sorts who use outboards daily and none seem to fuss about this as much as I do - at least the bar empties when I start to mention it..!
 

Andy,

If they use their motors daily, then the fuel will always be fairly fresh.  If, on the other hand, your small outboard sits idle for weeks on end, any fuel left in the pipes and carburettor will probably become stale.  There's then the potential to cause the sort of fuel problems that have driven me up the wall with two different engines.  Large engines (and lawn mowers) don't seem to suffer in the same way.

An economy solution to the problem is to use garage-bought petrol during the season but to run it dry just before the season's end.  Then run some Aspen 4 through it on the last few days of use.  It will still be in good condition the next season, allegedly.  I'll let you know how I get on next spring, when I've been through the full cycle.  I'm not worried about cost as I use so little fuel anyway.

The Tohatsu website says that the water/fuel filter is particularly recommended if you use fuel with ethanol in it, as the latter more readily attracts water.  If I still have problems despite the Aspen, then water in the fuel from condensation will be the next thing to worry about....

[Peter Taylor]

And none of this answers the question of why my lawn mower - that I fill with last years ob fuel, never gets even an oil change just keeps on going - started second pull this year with fuel in it that I left in from last year....

It's because mowing the lawn is much less pleasurable than sailing.

[Peter Taylor]

I've now installed a Unikas UF-10K Fuel-water separator filter which is claimed to trap "over 99% of any water that may be present in the tank". It's advertised in the States as an accessory for Tohatsu (and other) outboards (the filter is distributed by Tohatsu America Corp.) but I couldn't find a UK source so bought it via ebay from 411-Marine who were advertising the filter assembly plus a replacement filter for $85. With shipping costs it was about £100.The filter offered by my Tohatsu dealer in the UK was about half that price but significantly more bulky and harder to accommodate than the Unikas version.

Whether this was worthwhile or a waste of money remains to be seen! I use a fuel additive which, if it works as claimed, will mean the filter collects no water... only time will tell! I'll report back at the end of the summer.
Peter

[Nick Orchard]

Following warnings from a variety of sources, this forum included, I've just fitted a Yamaha filter/water separator unit for the 9.9 Yamaha on my BC26. It's rather larger than necessary as I didn't realise that Yamaha sell two versions, one for engines up to 70hp and another for engines up to 300hp, so my large version will allow me to fit a 300hp engine - should get me home a bit quicker! It has a paper filter to keep sludge etc out of the engine and any water in the fuel should separate out and settle at the bottom of the plastic bowl as it's heavier than the fuel. A red plastic ring will float on the water so it should be easy to see if there's any in there, in which case it can be drained off via the screw fitting on the bottom. The small version is about £70 and available from e.g. Bottom Line Marine. I understand that all petrol now has at least 5% of ethanol in it and is labelled 'E5' on the pump, but this may go up to 10% or 15% in future in order to meet emissions targets, so the problem of water in fuel is only going to get worse.
Nick

[Peter Taylor]

Hi Nick, by coincidence I just discovered the Yamaha filter on Ebay this morning. I assume it goes in the fuel line to the motor and therefore can be fitted to any outboard, not just Yamaha. It's cheaper than the one I bought and available in the UK which is an advantage when it comes to replacement filters.
Peter

[Nick Orchard]

Hi Peter
Yes there's nothing Yamaha specific about the filter and I'm sure it would be fine with any make of engine. Fuel goes in one side and comes out the other, hopefully cleaner and drier. Another advantage of buying the smaller filter is that I think it has the same 6mm pipe connections as Yamaha use for the fuel line on their small engines. The larger filter has 8mm or 10mm connectors, so I had to buy some 8mm pipe and 8mm-6mm in-line connectors (£3.99 on Amazon), so not a significant cost.
Nick

[Matthew P]

Here we go (or not) again.  After having two outboards last year clogged in carburettors with probably ethanol induced gunk and "varnish" I'm paranoid about fuel system cleanliness.

I have 9 year old external plastic tank and fuel line with bulb.  The fuel line and fittings I shall replace with new on the principle I can't see what's inside.  The tank itself looks clean through the filler cap - but is it?  Has it got "varnish" contamination stuck to the inside?  How can I tell?  How can I remove it? Does it matter?

Matthew
Gladys BR20   

[Peter Cockerton]

Mathew

My Yamaha 4 hp very rarely gets used but always starts. I add Sta-bil marine fuel 360 to the internal tank and after running the engine in the bucket I turn off the fuel and allow it to run dry the fuel available to it. Every two weeks I do this over the winter and after running dry it takes normally eleven pulls to get the fuel through again and start. After that 1st pull to start it again. So this works for me. I change my own impeller; fuel filter, engine oil, and marine quality grease the bits that need doing annually. The external tank is kept empty of fuel between uses along with the feed hose and priming bulb.

Peterc

[Nick Orchard]

Having just collect my 9.9 Yamaha engine from its annual service yesterday I thought people might be interested in the thoughts of Chris Hoyle of Kingswear (Dartmouth). (Only took him 2 weeks this year, down from 3 weeks last year). (Mind you it cost an eye-watering amount - 40% more than a 10,000 mile service on my Tiguan at a VW main dealer!). Anyway, enough moaning, here's what he said when quizzed on the problems of water in fuel:

1. He recommends not buying cheap supermarket fuel. He reckons that after a while it turns from the pale green colour of new fuel to a brown colour, and it also loses its smell, so pay a few pence more for 'proper petrol'..
2. Don't use fuel more than 4 weeks old - put it in your car (no not the diesel one!) or lawnmower - how big is his lawn??
3. Don't switch the engine off to stop it, disconnect the fuel line while it's running and let it run dry.

He actually told me all this last year, but I have to confess that I've studiously ignored it all. I've used Sainsbury's fuel, I've never stopped it by disconnecting the fuel (turning the key is so much easier), and the can gets re-filled when it's empty. I've had a half full 12l tank sitting there all winter but it started pretty much first time before I took it off for the service, and that was after clearing the snow out of the cockpit! I asked Chris what state the carburettor was in when he serviced it and he said 'fine!'

I also looked at the colour of the fuel in the bowl of my filter/water separator today and it's still looking green and it smells very like petrol. I can also report that after running about 30-40 litres of fuel through the engine over the last year, the red ring that indicates the presence of water in the filter is still sitting firmly on the bottom.

I expect that I'll be now punished for ignoring all these wise words by the engine packing up next time I'm just about to park it in the marina - I shall report again in due course!

Nick
BC26 008 Luminos II

[Graham W]

It’s time to revive this topic.  There’s an article in the Times this morning about the amount of bioethanol in standard UK garage petrol being doubled to 10% from next year.  The idea is that although the net net effect on CO2 emissions from this move will be small, it will stand us in good stead once they’ve worked out an economic way of producing bioethanol from forestry waste, algae and baby foxes instead of from crops.

So if you’ve ever had any outboard carburettor problems from using E5 forecourt petrol, they’re likely to get even worse from next year with E10.  You have been warned.....

[Sea Simon]

Very much agree with GW, below, on this.
The new EC10 petrol spec is all over the news today!

 I've got no experience of this grade of fuel (perhaps our foreign readers may able to illuminate?) But I'm sure it's not good news for small 4 stroke outboards, nor for users of older petrol cars?

I'd stockpile more Aspen, but I've neither the money nor storage space since we "prepped" for the coming covid apocalypse ?

Is it a conspiracy!?!