REMOTE FUEL TANK

[grahamcamm]

Is it possible to fit a remote fuel tank to a silver century plus? How would I go about it if it is? Thanks

[Charles uk]

Due to the Century's lack of a fuel pump it is not possible to fit a remote tank in the normal way without considerable engineering work on the crankcase.

A lot of Seagull racers fit a remote tank by modifing an old fuel cap to permit a remote tank hose fitting connector to be screwed into the fuel cap, by doing the following.

Remove cap retaining wire & air bleed screw & associated bits from Bakerlite Seagull cap,

A threaded brass bush will be seen in the center of the cap, this will have to be drilled & tapped to a 1/4" BSP parallel pipe thread. Tapping hole size 11.80 mm.

The air vent groove in the side of the brass bush should still be present after the thread has been tapped. now all you need to buy is a 1/4 BSP motor end fuel fitting which normally comes with a tapered thread, just screw this into the cap without the use of any thread sealer tape or gasket goo.

Now when you blow into the inside of the fuel cap,air should be heard to escape from the air vent groove. Failing this, the groove will have to be deepened with a needle file until it does.

Remove the existing fuel cap which will now only be used for transporting your Seagull, & replace with your modified one.
Connect your remote tank with it's standard pipe with a bladder pump.

To fill tank just squeeze bladder until bubbles or fuel start to escape from the air vent, Hey presto tank is full!

This can be done safely when under way with having to stop the motor & stand up in the boat, hanging over the transom.

With a bit of luck HA will post some pictures that he took of one of mine the other day to give a clearer picture.

[Horsley-Anarak]

Here are a couple of pictures of the one that Charles made, sorry about the quality of the pictures mobile phone camera.






Mk2 almost in the water

H-A

[Vic]

In theory it is relatively simple to engineer.

You will need:

A small fuel pump, preferably one that has a separate connection for the pulse line (otherwise an adaptor will have to be made to fit a pulse line)

A threaded hose barb that can be fitted to a hole drilled and tapped into the crankcase.

A fuel connector for the tank, a few bits of fuel hose and a handful of clips.

Add a couple of homemade brackets to support the pump and the fuel connector and the jobs as good as done!

The system could be embellished by incorporating a change over tap to switch between remote tank and pump and the integral tank. In fact even that's not necessary, The two systems are merely Teed together . When the remote tank is disconnected the connector seals the inlet, opening the tap on the integral tank enables that to be used. (same arrangement as on other outboards that can use either.)

The feasibility depends upon there being a suitable location to drill and tap the hole in the crankcase for the pulse line connection. Subject to that the project could well be a goer for someone with the right engineering skills.

How was it done on the 125 and 170 models? I wonder if any of the bits for those would be suitable.

[Charles uk]

On the 125, 170, Kingfisher & the 5R is was done with a crankcase pulse operated Amal fuel pump as detailed in the parts book.

But it was only used in conjuntion with the Amal 420 carb, fitted with the rubber tipped brass needle valve, as the 416, 418 & 419 Amal carbs seem to have insufficient needle valve closing pressure to prevent over fueling at anything much above tickover.

The manually pumped gravity fed system as used by the racers seems to be the simplest, cost effective & reliable way providing you remember to give it a few pumps on the bladder every 15 minutes or so depending on how hard your using your Seagull.

[grahamcamm]

Thanks for that Charles, it sounds easy enough and thanks for the pics HA it looks a neat little solution.

[Charles uk]

There are several styles of male & female tank fittings, just find the cheapes ones you can, a 1/4 BSP barbed fitting would do the job for a lot less money if you can find one.
In that case you would just have to push the fuel pipe on to it & hold with a cable tie or a jubliee clip.

Just remember to make sure that there is a working air vent!

The way I've done it probably costs £30.00 in parts if you've got an old fuel cap, but when you disconnect the remote tank & put it in the back of the car the fitting on the end of the pipe stops it leaking out when the car gets hot.

[timer]

I realise this an old thread BUT

How do you know when the tank is full or do you just wait for fuel to spill out? Roughly how long or how many sqeezes to fill the tank from empty? Would there be room in the cap for a knitting needle with a float on the bottom to also be arranged in the fuel cap as a level gauge? (it could float up and down through the cap if there's room alongside the connector)

I'm thinking of a trip on the Thames but am ashamed of the amount of petrol I seem to spill on refuelling

Has anybody tried the bike pump fitted to a tyre valve on the remote tank to pressurise it

What method is the most successful?

[Charles uk]

When the tank is almost full you get a few bubbles out of the air vent, like badly poured beer.

As for the number of pumps that depends on the size of your bladder.

Try it first without the fuel gauge, then make the decision if it's worth the extra effort.

During the summer the Thames is not the best place to run out of fuel, there are a lot of Sunday drivers on there in plastic gin palaces, that wouldn't see you hanging over the transom with a fuel tank in your hands trying to fill up in their wake.

The blessing with the hand pumped system is that you can do it with the motor running whilst under way, something that might not be the smartest move if you were pouring it in the tank from a can.

I just pump when in a lock as no one can tell, you have to stop the engine in there, but you can't pour fuel in there.

It is possible to fit a Kingfisher remote fuel system to a Century but finding all the required bits might well prove almost impossible & very expensive & would require carb & crankcase modifications.

I've done a couple for myself & H-A has done one, but it's not a job you'd undertake lightly.

[electrosys]

Perhaps I might tack-on an enquiry related to a round-tuit idea I've had for a while ?

Some time back I salvaged a fuel pump from an old scrap Perkins 2-stroke (c.16HP ?) - and from Googling around it appears to be a pretty standard job, with IN and OUT pipes and an air pipe (from the crankcase) driving the diaphragm. The diaphragm itself is a sheet of very thin rubber which is also cut in such a way as to form IN/OUT flap valves.

Rather than pump the fuel directly to the float chamber, my idea was to insert a T-piece into the existing fuel line, with a small rotary tap to one side of the 'T', so that the existing fuel arrangement could still be used 'as standard', with a second rotary tap fitted into the crankcase air line, so that the diaphragm could be disabled when the pump wasn't needed (be kind to your diaphragm !). Then, when on a long trip, simply attach the remote fuel tank by a fuel bayonet connector, and turn on the two taps.

The reason I didn't proceed with this, is that I couldn't identify a simple method of judging when the outboard's tank was full ... well, short of letting fuel escape from the filler cap's bleed hole - messy.

Of course, such a re-fuelling system wouldn't preclude pumping to the float chamber directly - simply turn off the outboard's tank tap, perhaps using that tank as a reserve ?

But - Charles raises an interesting point - would the float chamber valve of an Amal 2-jet be capable of stopping the flow from a diaphragm pump ?

[Charles uk]

Twin jet carbs can only handle gravity feed.

Amal 420 & 416 carbs that are fitted with the large diameter rubber tipped needles are the only carbs for a direct pumped application.

The pumped version of the Osprey was the only motor fitted with the modified 416, making that carb very rare & expensive, Seagull have none in stock.

I think I have 1 spare one, & know one guy who has a late model grey needle roller crank one, who's crank died, & he offered me the bits for a large fortune., I could ask him if your desperate.

[timer]

Hi Charles - thank you for that it seems sensible advice. I normally sail/cruise in my Wayfarer dinghy and use the seagull extensively. Guess its done around 1000 miles all told! Its 40+ and I fitted clutch from John - it used to oil up at low revs which was a real nuisance I can now rev it out of gear to clear it. I've got siba recoil off John for Thames trip and will leave mast and sail behind but use land and boat tent for a bit of coolture. I was worried about having to squeeze the bulb for ages (don't shake hands after trip!). I won't fit float yet as you suggest.

Two other queries - is it worth testing compression as its getting old? I've fitted new oilseals and 25.1 needle or should I not bother. Also the impossible is it possible to reduce the noise - I've tried earplugs but they make little difference. I have a plastic (not rubber) carb cover will that make any difference

[Ian Malcolm]

What's needed is a small engine mounted reservoir with either its own float valve or an overflow back to the tank. That would then give gravity feed to the carby (or to the original tank as well) with no risk of excess pressure or overflowing.

[The Tinker]

Like Charles says the seagull carbs only handle gravity feed. I have tried a few of the mentioned systems, vacuum or pulse pump was a pain in the butt failure, ended up wrecking a crankcase. A bike pump to pressurize the remote tank worked ok for a while until the fuel fumes wrecked the seals in the pump so ended up using the hand pumped bladder as shown in HAs pictures, I have added a float in the tank to show fuel level. Not to hard to operate and very simple. Also easy to change to another engine.

[timer]

Tinker - how did you make the float - did you need to braze another boss on the tank? Were your fuel connectors the same as Charles? Thank You