See full version: Optimax with low fuel pressure
It is a 2001 225hp Optimax that shut down the other day and just cranks now without starting. I hooked up a fuel pressure gauge and when I turned on the key the first time it only went up to 20psi. I had to cycle the key on about 6 times to get it to a max of 50psi. I hooked up the gauge to the other engine and it shot up to 60psi rite after the key was turned on the first time.
I had someone at the port side of the non running engine while turning the key on and the silver canister that looks like a old carter inline electric fuel pump was not sounding the same as the other engine. I think that this canister is or is part of the low speed fuel pump. more
Re: mercury 150 efi fuel pump
Check all your grounds and connections first but it sounds like the ECU , call Mrs Linda and tell her you want to send it in for testing (about $75). CDI charges about $800 to fix this problem but for around $300 more you can get a new adjustable ECU from Brucato. here
Re: mercury 150 efi fuel pump
To answer your questions directly, if power is to be considered as 12 volts, then both pumps are powered when the key is in the on position. That is, you will see 12 volts to the positive terminal of each pump with the key on. here
f250b no power to low pressure fuel pump
"f250b no power to low pressure fuel pump" more
Thank you for your advice, i notice that the port engine runs a pump for about 5-6 secs, is that the high pressure pump?, the one that is seized and hence no pump noise. should the the low pressure pump show voltage at cranking?
The ECU applies a ground to each pump to make it operate. more
Disconnect the fuel hose just after the mechanical pump, point it into a suitable container and have a helper crank the motor while you watch the fuel flow. You should have a strong pulsed stream of fuel, if not then you need to check the hoses, fittings, or possible need to rebuild that pump. more
Check these threads/sites to see if a copy of your service manual is still available, the troubleshooting section will explain further testing, repost any questions and your findings. here
Re: Mercury 200 EFI Fuel Pump Issues (First boat blues)
There is a mechanical pump that feeds the vapor separator which contains the high pressure pump. more