Suzuki DF50 Fuel Pump issue

[Ole2708]

Hi
I´m having an DF50 from 2003 with 202Rhs and I’m dealing with following problem:

Eng. Is starting end runs idle without problems.
I can go full load for approx 2-3 min. After that it goes to approx 1000Rpm. I keeps running in idle and allows me to go back on full load, now in less than 1 min.
If I pump at the priming bulb during the drop it raises in Rpm immediately.

Following parts has been changed/renewed:
Low pressure fuel filter.
Low Pressure fuel pump diaphragm Set.
Spark plugs.
fuel line with primer bulb.
Non return connection at tank.

Tested with another tank/fuel line/bulb – same symptoms.
Fuel line connectors in engine casing bypassed – line connected directly at low pressure fuel filter – same symptoms.
High pressure fuel filter bypassed – fuel line connected directly at high pressure fuel pump and to the rail – same symptoms.

I´m suspect the High pressure fuel pump to cause the problem, any good ideas?

Brgd.

Ole

[keakar]

have you tested the fuel line pressure from the pump? this will tell you if the pump is working ok or not

it may also be a blockage in the high pressure fuel pump screen at the bottom intake on the pump or even as simple as the float needle isn't filling the vapor separator with enough fuel so take it apart and check it

intake manifold needs to be removed to access it.

[Ole2708]

Hi Keakar,

Thanks for your reply.

If I turn the ignition key fuel pump is running and if I open somewhere at the rail fuel is coming out.
So I suppose pump is working.
Haven’t tested with an pressure gauge, during sailing at full load...

I will take the HP-Unit apart ASAP.

Brgd.

Ole Ø.