Boat Maintenance & Repair Forum

Electric fuel pump

by NickT » 30 Oct 2016, 19:42

Hi chaps,

I have a problem with fuel starvation and I think I have narrowed the problem down to the fuel pumps.

As the engine is 16 years old I am finding it hard to source diaphragm repair kits so am considering bypassing the mechanical pumps and fitting an electric k&n pump.

Spec for the merc pumps is up to 7 psi and 67 litres an hour.

Multiply x 2 gives a throughput of around 134 litres an hour. Bearing in mind that my fuel tank is 80 litres and that would last for about 5 hrs I think the k&n pump at 160 litres/hr should more than cover the carbs requirements.

It is self priming and regulated plus I can dispense with the traditional squeeze bulb in the fuel line.

Does anyone have a view on any pitfalls please?
NickT
 
Posts: 126
Joined: 04 Dec 2014, 19:56
Location: Southampton, Hamble River

by Ianfs » 31 Oct 2016, 04:55

Only issue's I can see are, electric fuel pumps don't like running dry, also if your engine uses 80 litres in 5hrs that's 16 lph which is a lot less than 160 lph. Do you think the extra pressure/flow will affect the needle valves i.e. the extra pressure may cause flooding?
Ianfs
 
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Joined: 24 Nov 2014, 18:40
Location: Hampshire, by the Sea

by NickT » 31 Oct 2016, 07:16

Hi Ian,

I don't know if that will be an issue.

The costs of repairing the existing pumps may well exceed the cost of an electric pump at£60 by a large margin.

I have contacted a mercury dealer to check spares availability and await their response.

Of course this may not solve the problem but would eliminate one aspect!

If this doesn't work then a strip and rebuild of 4 carbs in likely. If I do that then I may remove the air restrictor and fit larger jets to update to 90 hp at the same time. (Dennis thinks that I have rebadged a 115 merc anyway).

Good job the season is over as I would be champing at the bit with this fault...
NickT
 
Posts: 126
Joined: 04 Dec 2014, 19:56
Location: Southampton, Hamble River

by Ianfs » 31 Oct 2016, 08:45

Are you still getting die back?
Ianfs
 
Posts: 1428
Joined: 24 Nov 2014, 18:40
Location: Hampshire, by the Sea

by Gazjen » 02 Nov 2016, 20:17

Usually electric fuel pumps are wired through the oil pressure switch too so if the engine stops the pump does too.
Gazjen
 
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Joined: 19 Jun 2015, 02:13


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