Fitting a diesel bleed to fuel tank in situ

Swanrad2

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Hi,
We have just fitted a new Beta 20 and realised afterwards that we need a bleed from the injectors to the fuel tank. I really, really don’t want to take the engine out again but with limited access how do I get the bleed back into the tank?

The diagram suggests a pipe down towards the bottom of the tank. I can tap and fit a bulkhead fitting but would need at least a 16mm hole drilling (probably 20mm+)to get the 16mm OD pipe in. Not keen. Anyone got any alternative suggestions?

Also does it need the pipe to below fuel level to prevent anything like back pressure, or can I just let the excess diesel drip from the bulkhead fitting?

Probably dead easy and I’m over complicating, but we’ve spent a few quid and a few hours in this engine and don’t want to mess it up in the final straight!

Cheers
 

NormanS

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The fuel returns on the various boats that I've owned, have gone into the top or very near to the top of the tank. I am unfamiliar with your engine, but surprised that the fuel return pipe is as big as 16mm.
 

BabaYaga

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I installed a 20 hp Beta 722 in 2006. In the fitting instruction at that time there was no mention of a dip tube for the fuel return. Mine just goes to a fitting on top of the stainless steel tank and I have had no problems from this arrangement.
 

VicS

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Hi,
We have just fitted a new Beta 20 and realised afterwards that we need a bleed from the injectors to the fuel tank. I really, really don’t want to take the engine out again but with limited access how do I get the bleed back into the tank?

The diagram suggests a pipe down towards the bottom of the tank. I can tap and fit a bulkhead fitting but would need at least a 16mm hole drilling (probably 20mm+)to get the 16mm OD pipe in. Not keen. Anyone got any alternative suggestions?

Also does it need the pipe to below fuel level to prevent anything like back pressure, or can I just let the excess diesel drip from the bulkhead fitting?

Probably dead easy and I’m over complicating, but we’ve spent a few quid and a few hours in this engine and don’t want to mess it up in the final straight!

Cheers

One boat I sailed years ago ( with a Watermota engine) had the spill back line just poked through the side of the tank filler hose !

A bit Heath Robinson but it did not cause any problems
 

VicS

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Into the (spare) inlet on the fuel filter?

Have you thought of asking Beta?

Its reasonably clear in the Beta Installation instructions

t9wghy.jpg
 

NormanS

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Its reasonably clear in the Beta Installation instructions

t9wghy.jpg

Yes, it definitely shows the return going down into the tank. I can't think of any logical reason why it should.

That drawing also shows a drain at the lowest point of the tank. How many have?
 

elenya

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We have a spill return that goes to the fuel supply line upstream of the filter. Same setup since 1981 and still fine with the original engine. Why not ask your local agent if a similar setup is ok? If not then the idea of a return to the fuel filler line seems reasonable and perhaps simplest.
 

DownWest

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Can't think of any reason to put a dip pipe for the return. I worked with a 'few' Lister gensets and the return always went to the top of the tank. I am not so keen on returning the injector spill to a filter, as that might keep air in the system, rather than just put it in the tank.
 

Heckler

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It's to reduce aeration and foaming of the fuel.
Plus one of the design rationals for fuel return is to cool the injectors, taking it to the tank gives the warm return fuel time to dissipate its heat into the tank. I know some manufacturers plumbed the return in to the fuel filters, but as you have said and also because of the heat dissipation I feel that is a mistake.
 

DownWest

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See post 10.

I do try to read all the posts before hitting the keys... And I did read that one. But I would think that hot fuel and foaming might only be an issue if you were about to run out of fuel.
The Lister manuals all put the spill back in the top of the tank. From the little 3KVA up to the 50KVA sets I worked on. OK, not modern stuff, but fairly well alighned to boat engines.
 

carpetsauce

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I've just collected a 25 litre fuel tank for my harbour launch (fuels a beta 14hp). Its return fitting doesn't couple to an internal pipe, which would take the fuel below the tank fuel level. It'll just dribble the returning fuel into the tank from the internal end of the return fitting. So I'm so pleased that from the posts above it doesn't appear essential for the return fuel to be fed below the level of the fuel in the tank. I take the point about hot fuel and aeration etc, but for my purposes a simple dribble-from-the-fitting system will be fine. (Not fitted yet, so here's hoping ...)..
 

BabaYaga

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In my manual from 2006, as well as in the current one, Beta stresses the importance of returning the excess fuel to the tank, not to any point in the fuel line. "This will prevent air getting into the system".

I agree with what is stated above, that the requirement for a dip tube in the return line is probably to reduce foaming. But as this was not mentioned in earlier manuals, I would guess it is not too critical...

Beta%20manual%20fuel%20system.jpg
 
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