Safety - water in fuel

[SteveWD]

Earlier this week we had to call out the RNLI because the engine on our BC26 failed not long before dusk in a strong tide (and, before you respond, no, we couldn't sail into Christchurch and into our berth).

Cause? Water in fuel stirred up by a rolly sea. Despite liberally adding the recommended water-dispersing additives it still accumulates. Modern ethanol-laced petrol is far more prone than pre-ethanol petrol to absorbing water and then dropping it out into the tank as temperature and pressure change.

Common recommendations are to use up fuel within six weeks and replace with fresh - difficult in a boat with a large fixed tank like ours. Modern practice in petrol-powered boats with fixed tanks and low usage is to include at least one water filter and/or a an observation glass or water detector. If you have removable tanks, you should empty them completely fairly regularly.

Ignore at your peril - we discovered our problem in benign conditions an hour before we needed the engine and the Coastguard and RNLI were able to deploy in good time. It could easily have been a different outcome in other conditions.

[Peter Cockerton]

Steve

Forum post on this subject

http://www.swallowyachtsassociation.org/smf/index.php/topic,1377.msg10563.html#msg10563

Peter Cockerton

[Graham W]

If you mostly sail and use your outboard infrequently, you are at risk of stale fuel misery.  In addition to the ethanol attracting water into your garage-bought petrol, it may end up varnishing the inside of your carburettor and clogging your jets.

The thread that Peter points to discusses this (earlier on) and suggests water/fuel filters, additives and alkylate petrol as possible remedies.  I've gone for the latter (Aspen 4 petrol), which costs thee times more than garage unleaded but ends up costing me less because I don't have to keep paying someone to unclog my outboard.

[SteveWD]

Thanks for the useful link to the other thread on filters. As someone in the thread said, diesel systems include filters and water traps, so why don't petrol systems?

We use our Mercury 9.9 engine frequently and have a large fixed tank to give us a 150+nm range. A cruising boat with a fixed tank gets its fuel from marina and dockside pumps, so whatever is available gets used and we haven't seen alkylate fuel obviously available there. Since additives are ineffective, filters seem the only option. Our tank and pipes are are about to be drained, so we will be having a filter fitted then.

[Nick Orchard]

Hi Steve - As you probably noticed in the other thread I fitted a Yamaha filter to my BC26. I found a useful space to mount it was up inside the bulge at the back of the locker, (I can send you some pics if you'd like more info). It's fairly accessible and easy to see the red water indicator ring without a torch etc, and it's also out of the way. I have two 12l removable tanks so I guess your fixed tank arrangement will be a little different.
Re the Aspen 4 fuel, this is recommended for garden machinery (strimmers etc) and our local garden machinery dealer sells 5 litre cans for £19.55 (ouch!). I'm still using forecourt petrol and haven't had any problems so far (touching a lot of wood), and some of the fuel has been in the tank for a lot longer than 6 weeks. The filter has been in place for about 6 months now and still no hint of any water in it.
Nick

[Peter Taylor]

Steve, a couple of suggestions:

(1) given you have a fixed tank, does it have a permanently open breather? If so I would check whether its possible to install a method to close it when the motor is not in use.

(2) When topping up my removable tank I always use a funnel with a filter designed to filter out water. The petrol seems to go through remarkably fast, and also you can get larger versions of the funnel - it may not be impracticable to filter the petrol using a funnel as you fill up at a marina pump.

The inline fuel filter which I've installed (see previous thread) has not yet trapped any water as far as I can see. On the other hand I don't motor that much, so there could be water in the fuel tank which has yet to reach the filter.  Apart from emulsifying the water (or whatever it's supposed to do with it) the fuel additive which I use is supposed to prevent the varnishing job which Graham alludes to. Whether it does any of these things, I've no idea, I guess you only find it doesn't when the motor stops!

Peter

[Rob Johnstone]

Back on the soggy problem of stale petrol and the misery of starting outboards....I've just purchased a factory fresh Mercury 6 ( Freddy 2 ., Freddy tribute ?) and was given a lecture on the problem by the chap who sold it to me (name and address supplied on request). His informed view is that It's not stale fuel in the tank or the carb that's the trouble, it's petrol lying in the "rubber" tube between tank and engine that's the real problem. It dissolves all sorts of compound from the tube that then affect its volatility. His solution is to drain the tube before leaving the engine for more than a couple of weeks. Any organic chemists amongst us care to comment?

By the way, the hull  of Riff Raff (aka Vagabond 2) has arrived at Gwbert.
....

[Woodlark]

This links into a previous thread on poor starting when it was suggested to start the outboard by using the built in tank and then switching over to the remote tank. I will give it a try (petrol in both areas contains 'preservatives').

[Barry C]

I posted this last month on a different thread, but no one replied. Sorry to repeat it, but this may be a more appropriate place for the question:

I'm curious to know whether anyone has experience with (or opinions about) the newish Tohatsu 5 hp propane (LPG)-fueled outboard.   

http://www.tohatsu.com/outboards/5_4st_lpg.html

Propane has a variety of interesting advantages (and disadvantages) compared to gasoline. The only commercial competitor to the Tohatsu seems to be from Lehr, which may have reliability problems. The prospect of avoiding ethanol issues is certainly a plus.

[Peter Taylor]

it's petrol lying in the "rubber" tube between tank and engine that's the real problem.

Rob, that's interesting... I'm beginning to realise that not all fuel lines are equal!

As I reported in the thread referenced by Peter C below, I've installed an inline filter between tank and outboard. To do that I purchased a new fuel line from Force 4 which was made by Moeller in the US and certified to EPA standards. It, and the priming bulb, gives the impression of being much better material than the original fuel line that came from the outboard vendor (which he recommended simply because it was significantly cheaper than the official Tohatsu tank and hose). That cheaper hose is a black rubbery material throughout. The new hose is grey and feels more plastic in nature with a double layered construction which includes nylon reinforcing and also has a slightly wider bore. A similar looking hose ( http://www.marinescene.co.uk/product/1685/universal-fuel-line-and-bulb ) is described as alcohol resistant and meeting "SAE J1527 B2 and ISO TYPE B CLASS 2". Looking up SAE J1527 I find it concerns, inter alia, the permeability of hoses to fuel containing up to 10% ethanol.

At present I'm still using a length of the old black hose to connect between the inline filter and the outboard but I'm beginning to think I should use the left over bit of the new grey hose for that as well. But of course, for all I know, the black hose may actually be the superior one! Also, of course, I'll continue with all the incantations and other ceremonies I've adopted to ensure (touching wood fervently) that the outboard starts!

Barry C... I suspect that we are all waiting for you to get a Tohatsu propane outboard and tell us whether it's any good... I'd certainly be interested to know!

Peter

[Rob Johnstone]

Peter, "inter alia" eh that's the second I've come across those words today. Things must be looking up!

[Barry C]

Barry C... I suspect that we are all waiting for you to get a Tohatsu propane outboard and tell us whether it's any good... I'd certainly be interested to know!

Peter

Peter, I suspect you're right. One of my deep principles in life is to avoid being a beta tester of new types of outboards. Alas, reviews on this one are sparse, but I'm intrigued. Against my better judgement I may give it a shot in the spring. If so, I will report back with first impressions.

Barry

[Graham W]

Here's a propane enthusiast https://www.followingseas.media/blog/2017/2/22/propane-power-is-here.  He makes a good case for it.

[TimLM]

Hmm propane, when converting buses to propane we came upon a difficulty, namely far more heat to dissipate. So a marine use would seem to be ideal. I wonder if you get a conversion kit?
Oh and the byproduct was water!