1997 Mercury 200 HP EFI Electric Fuel Pump won't turn on with new stator

[russbriere]

At the end of last summer my Merc 200 EFI was experiencing rough idles, stalls & rough starts later in the day. Cold starts were great.
After replacing all fuel lines, pick-up, primer bulb, mechanical fuel pump, battery, spark plugs, switch boxes & voltage regulators, I made the mistake and had the stator replaced.
The boat cold-started fine before the stator replacement.
Now the boat won't even cold start.
I have spark on all 6 but no evidence of fuel at the plugs.
*The electric fuel pump won't turn on with the key on run or start.

I followed the manual & tested the electric fuel pump power & ground lines. Both passed. In fact, the pump turned on when I jumped the ground.
The manual's conclusion at that point was to replace the ECU. I checked all grounds & tightened the loose ones.
No evidence of arcing inside the ECU harness, but pin 2 was pressed in to 1/2 the normal length. Pulled it back out & it seems to be seeding just fine.

ECU power & ground tests both passed (pins 16, 6 & 7)

My next step is to have the ECU tested by a mechanic.
I'm not looking forward to my 4th visit to the shop.

Suggestions?

 

[DooDahDave]

Try doing a dynamic test on the power feed. Ground the pump so it runs, test voltage at the feed for the pump while it's running. If it's lower then battery voltage there'd a bad connection on the feed side. If not it's likely a bad ground. If the pcm triggers the ground when the key is turned, check the grounds for the pcm. (U can have a weak ground,and it will pass all static tests.)

 

[Dukedog]

probably pump driver circuit in tha ecu went south... pretty common with age.... disconnect "both" + and - from pump and tape 'em up... install a new ground wire to - from any motor ground... starboard side where all your electrics are you will find a small plastic terminal with a purple wire.. add a jumper from that purple to tha + side of tha pump... pump should run/stop when key is turned on and off... if there is no other problems tha motor will run/operate just fine for as long as you wanna keep it that way... one of our ProMax motors has been this way for over five years with no problems....

 

[russbriere]

Thanks for the tips DooDahDave & Dukedog

I have 1 question about the jumper for the fuel pump:

Where exactly do I find the small plastic terminal?
I found 4 purple wires converging on a vertical plastic terminal just left of the starter solenoid? (located above the switch boxes)

Thanks again for your help guys. I will be 1 happy boater if we get 'er started.
-russ

 

[Dukedog]

thats tha one... purple is a "key switched" hot.... lotsa folks do what we're talkin' about but add a relay for tha pump.. i use a relay... it cuts down on tha amp draw on tha purple....

 

[russbriere]

Good point. I imagine the little fuel pump doesn't require that much current to work.
What kind of relay do you recommend?

 

[Dukedog]

it doesn't, but.... try it out first... justa a little "cube" relay with a 20/30 amp cap main contacts... Summit.

 

[russbriere]

It started! Thanks so much Dukedog. I can't tell you how relieved I am.
Lastly, if I run it without the relay switch, can I damage the fuel pump?
I'm guessing the electric fuel pump is ON all the time the engine's running.

Meanwhile, I'm searching for the above part.

 

[russbriere]

https://www.summitracing.com/int/parts/sum-890023/overview/

this one's a 30Amp relay
That sound like a lot of current.
The main fuse is only 20A

 

[Dukedog]

like said.. got one that's been that way over five years with no problem...

that one will work ok.. you can "in-line" any size fuse ya want.. i fuse tha purple feed at 10 amps and load side goin' to tha pump at 30 amps.... bit much but it works and i also run a lot bigger pump.... and yeah, tha pump runs anytime key is "on"..............

 

[russbriere]

sorry to bother you again but the guy buying my boat was worried that my fuel pump will be running all the time (it was quite warm after a 10min run on the lake)
When it was working off the ECU, did it eventually turn off when the fuel psi is high enough?
I figured the mechanical pump would take over?

Thanks,
-russ

 

[Dukedog]

runs when ever tha motor runs... motor will not run unless that pump is runnin'..... all tha mech pump does is keep tha vst full to supply tha 'lectric pump....

after 10 minutes tha whole motor should be warm!

 

[russbriere]

awesome, I learned a lot in this forum
I appreciate your help!

 

[bradduncan]

I think I’m having the same problem. + side of fuel pump shows good power. Shoes no ground on - side. Make a Jumper ground to - side and fuel pump will turn on and motor will run. Remove jumper and it quits. Does that sound like the same issue?

 

[GA_Boater]

I think I’m having the same problem. + side of fuel pump shows good power. Shoes no ground on - side. Make a Jumper ground to - side and fuel pump will turn on and motor will run. Remove jumper and it quits. Does that sound like the same issue?

You should start a new thread. Old Inactive threads are often ignored because, well, they're old and inactive.

Closed.