1994 Evinrude 70 hp fuel pump/system problem help needed

[jrynearson]

1994 Evinrude 70 hp rebuilt six months ago. Took VRO off. Removed oil line, oil reservoir and wiring. Capped off oil intake at fuel pump. Obviously premix now. Engine has been running great except that after a couple of minutes at +/-4800 rpm I start losing power. If I squeeze the priming bulb the rpm's pick back up for a minute then start losing rpm again. Happens at all rpm, just happens sooner at higher rpm. Fuel system is completly new: fuel lines, fittings, racor water separator, suction stem in tank, priming bulb. Fuel pump is the original. Priming bulb fills easily and stays firm when engine is off so I doubt I have a fuel delivery problem to the fuel pump. Any ideas? Please help.

 

[Haffiman]

Re: 1994 Evinrude 70 hp fuel pump/system problem help needed

Dismantle the pump and check both air motor part and fuel section part. Kits are available, check: shop.evinrude.com under accessories for your year. Another option is to install the 'small' non-vro pump.

 

[jrynearson]

Re: 1994 Evinrude 70 hp fuel pump/system problem help needed

Dismantle the pump and check both air motor part and fuel section part. Kits are available, check: shop.evinrude.com under accessories for your year. Another option is to install the 'small' non-vro pump.

If I remove and dismantle the fuel pump, what am I looking for? Debris or tears in a diaphragm?

 

[Haffiman]

Re: 1994 Evinrude 70 hp fuel pump/system problem help needed

If I remove and dismantle the fuel pump, what am I looking for? Debris or tears in a diaphragm?

Leaking valves and damaged diagrams. However before tearing it down, hook the fuel hose directly onto the VRO pump to eliminate any leaking connectors etc.