700sci Fuel Pump blowing fuses, WHY?
08-05-2013, 09:42 PM
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UPDATE:
Changed to new fuel pump, problem solved!
I had the low and high pressure filters changed before the season started so didn't believe that was the problem.
Pump was it, no more blown fuses (back to normal 25 amp fuse too). Hopefully it STAYS fine
The Mercury 700sci pump IS the Aeromotive 11108 for $465 on Jeg's. I ordered it Friday AM for next day Saturday delivery for minimal extra money, and they GOT it to me Saturday AM!
How To: Swapping 700SCi fuel pump out is not hard, at least on the front engine in my staggered setup--
Pump is under the front of the motor just behind the harmonic balancer. You can slide it out sideways without taking anything else off.
Best to have AN wrenches for the gas fittings; a wratcheting socket and a wrench for the 4 mounting bolts/nuts and the 2 wires with small nuts on end of pump; and LED flashlights or light that will NOT spark or burst causing fire.
1) Turn off your fuel supply valves from the tanks.
2) Turn off the Electrical System for your boat at the main switches. Be aware that some systems may still be hot if some are straight off battery, BE CAREFUL!!
3) Remove the 2 nuts holding Positive and Negative wires from pump, move wires aside.
4) Remove the AN fittings from both ends of the pump. Easiest to do this while pump still anchored by at least one nut/bolt holding pump down, or the pump moves while you are trying to wrench off those big fittings.
A relatively small amount of gas drains out, from the hoses AND the pump as you tilt it; have a bucket for the gas to drain into. Empty out the gas bucket asap and clean up right away (flammable and it's a tight spot).
5) Remove the 4 nuts/bolts holding pump down.
6) Slide the pump out one side (side with electrical connections was easier)
7) Swap the two O-ring'd fittings on the old pump over to the new pump, need a couple of big wrenches to get those off.
8) Reinstall the new pump in reverse order of above steps.
9) Prime pump, it primed quickly by turning the key on and off a few times, without turning the motor over (boat out of water).
10) CHECK FOR LEAKS!! IF ANY LEAKS, POWER OFF and re-seat or re-do what is leaking. No sealant is needed, these are rubber O-ringed and AN type connections.
I am going to send the pump to Aeromotive to find out how much rebuild likely to cost...if it's over ~$200 I might just get another completely new one for $465 if the time comes...they are "rated" for 2,000 hours so "should not have gone bad".
Changed to new fuel pump, problem solved!
I had the low and high pressure filters changed before the season started so didn't believe that was the problem.
Pump was it, no more blown fuses (back to normal 25 amp fuse too). Hopefully it STAYS fine
The Mercury 700sci pump IS the Aeromotive 11108 for $465 on Jeg's. I ordered it Friday AM for next day Saturday delivery for minimal extra money, and they GOT it to me Saturday AM!
How To: Swapping 700SCi fuel pump out is not hard, at least on the front engine in my staggered setup--
Pump is under the front of the motor just behind the harmonic balancer. You can slide it out sideways without taking anything else off.
Best to have AN wrenches for the gas fittings; a wratcheting socket and a wrench for the 4 mounting bolts/nuts and the 2 wires with small nuts on end of pump; and LED flashlights or light that will NOT spark or burst causing fire.
1) Turn off your fuel supply valves from the tanks.
2) Turn off the Electrical System for your boat at the main switches. Be aware that some systems may still be hot if some are straight off battery, BE CAREFUL!!
3) Remove the 2 nuts holding Positive and Negative wires from pump, move wires aside.
4) Remove the AN fittings from both ends of the pump. Easiest to do this while pump still anchored by at least one nut/bolt holding pump down, or the pump moves while you are trying to wrench off those big fittings.
A relatively small amount of gas drains out, from the hoses AND the pump as you tilt it; have a bucket for the gas to drain into. Empty out the gas bucket asap and clean up right away (flammable and it's a tight spot).
5) Remove the 4 nuts/bolts holding pump down.
6) Slide the pump out one side (side with electrical connections was easier)
7) Swap the two O-ring'd fittings on the old pump over to the new pump, need a couple of big wrenches to get those off.
8) Reinstall the new pump in reverse order of above steps.
9) Prime pump, it primed quickly by turning the key on and off a few times, without turning the motor over (boat out of water).
10) CHECK FOR LEAKS!! IF ANY LEAKS, POWER OFF and re-seat or re-do what is leaking. No sealant is needed, these are rubber O-ringed and AN type connections.
I am going to send the pump to Aeromotive to find out how much rebuild likely to cost...if it's over ~$200 I might just get another completely new one for $465 if the time comes...they are "rated" for 2,000 hours so "should not have gone bad".
