xwing

700sci fuel pump is blowing fuses and relays, drawing too many amps.
Another member had the problem http://www.offshoreonly.com/forums/g...p-rebuild.html

I had to change relays 2-3 times, then noticed the relay harness was melted on one conductor so changed that relay socket (PITA due to short wires)

Then the 25 amp micro mini fuse for pump blew on water, put a 30 amp in to get home and that blew once, that fuse socked is blackened too, clearly drawing too many amps!

I am looking at Aeromotive Marine pump 11108 as replacement, I THINK it's the one Mercury uses, and Jeg's has it for "only" $465 instead of Mercury $989, $801 at discount seller.
http://www.jegs.com/i/Aeromotive/027...rentProductId=

Anyone else had this, did changing the fuelpump fix it? Were you able to have it rebuilt for price that makes sense?

Thanks!
JT
Oak Creek, Wisconsin

GPM

Could be the pump, could be a dirty filter causing it to draw more amps, just a thought.

RT930turbo

+1.

Never a good idea to up the fuse, especially when boats and fuel are involved, been there done that. It's there to protect the wiring, as evidenced by your melted socket. Sounds to me like the pump is on it's way out.

Pwraddr

We had the same issue on my buddies Donzi with 600 SCIs. Was the pump, drawing too much.

FIXX

iTrader: (2)

+2 fuel pump drawing too much amperage,, why is you you to determine,..as for the wires malting make sure the connectors are tight to the relay blades..keep a eye on it because it could catch fire..

GPM

You can put an amp meter on the pump when it's running and see what it's using.

xwing

Thanks for the replies and help!
I'm going to change the high pressure pump, and check/change the high pressure post-pump fuel filter.
Aeromotive says to draw 30 amps head pressure would have to be over 100psi on this model 11108 pump, so suggested changing the post pump filter; drawing that much amperage even from clogged filter only could damage pump in and of itself so recommends sending it in for check/rebuild anyway. Pump is rated for 2,000 hours so our 275 hours is well within design service life.

xwing

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. Pay attention to the Inlet side 90 degree fitting, that you orient it the same as the old pump had it, so it will mate up to the supply line fitting easily. These stiff hoses/AN fittings don't like angulation.
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".

MarkDonzi

Just changed mine with Merc 600SCI, merc manual doen't give amperage but mine was drawing around 17 amps at idle and blew the fuse. Checked the other motor and was only drawing 5 amps. Had to change the fuse block out because when fuse "blew" it actually melted the fuse connector.

Had the boat out once since changing the pump and no issues other than throwing a blade on a prop:/

Does JEGS have an equivalent after pump fuel filter that matches up woth merc's??

Thanks, Mark

xwing

MarkDonzi:
I don't know if Jeg's has the matching fuel filter for the Mercury setup. Aeromotive seems to use a different filter setup on their website, a 100 micron prefilter and then a post filter they have.

Where did you get a "matching" 4 micro mini fuse harness like Mercury has? Is that what you mean by fuse block, mine has two identical looking fuse blocks that have 4 fuses each with a black cover over each, just stuck to the front side of the mounting place for the PCM computer and all that, at the back of the motor. The 25 amp fuel pump fuse was in there, and mine is a little blackened/melted a bit too.

I updated my post above with a better "How To Change The Fuelpump" step by step.