Mercury 50 elpt efi 4s no ignition

adolfo

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Apr 6, 2012
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I have a Mercury 50 hp ELPT 4 strokes , s/n 1C084939 Set 2008, recently change out the battery.
I hooked battery leads up to reverse poles.
I blew two fuses , the 15 Amps fuse (Main Relay/Accesories) and 25 Amps fuse (Main circuit). I replaced both , and correct the battery leads connection.
I have a problem , the 15 Amps fuse (Main Relay) blow , when I try to start the engine .
Power Trim works Okey.
Our Mercury dealer is 2000 km far , so I need solve this issue.

1- I disconnect all the boat accesories (Light, radio , pump, etc)
2- Battery voltage is 12.8 v

Thanks in advance for any help , I am a new to Iboats.
 

Fun Times

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Re: Mercury 50 elpt efi 4s no ignition

The service manual is calling for #17. Main power relay/accessory circuit to be a 20 amp mini fuse not 15 amp.

Try a 20 amp and see what happens, Make sure all the wires (in particular the Red with Purple) do not get hot going to the fuse and the main power relay when you first turn it on with the bigger fuse though.

14. Main power relay
15. Main power circuit - 5 amp mini fuse
16. Fuel pump/IAC/injector circuit - 20 amp mini fuse
17. Main power relay/accessory circuit - 20 amp mini fuse
18. Ignition coil circuit - 25 amp mini fuse
19. Diagnostic circuit - 2 amp mini fuse
20. SmartCraft data bus circuit - 5 amp mini fuse
21. Stator
22. Voltage regulator/rectifier
23. Start solenoid
 

adolfo

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Re: Mercury 50 elpt efi 4s no ignition

fun time ; thank for your information , I replaced the fuse (20 Amp mini fuse) , and the fuse blew up again.
I measure the voltage in the start solenoid , when I try to start the engine , the voltage drop to 10 volt.
Could be a short cut in the start solenoid ?
How I can test the solenoid ?
best regards
 

mikesvr6

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Mar 2, 2010
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Re: Mercury 50 elpt efi 4s no ignition

Hello, i have just been offered 50 hp 4stroke mariner that was reverse polarised. Any help would be great, it also has the 2 fuses blown and The main relay one was 15amp not the 20 stated in the manual.
Thanks
 

adolfo

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Re: Mercury 50 elpt efi 4s no ignition

Hello, i have just been offered 50 hp 4stroke mariner that was reverse polarised. Any help would be great, it also has the 2 fuses blown and The main relay one was 15amp not the 20 stated in the manual.
Thanks

hello mikesrv6;
I don?t know the year of your Mercury engine , if up to 2002 , you must check , Supression diode (probably is in shorted) and measure diodes and SCR of the Voltage Regulator (probably open both).
I replaced both and the engine ran.
If you need more information ,please ask me.
best regards
eduardo
 

mikesvr6

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Re: Mercury 50 elpt efi 4s no ignition

the engine is post 2007. would that make a difference ?
 

adolfo

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Re: Mercury 50 elpt efi 4s no ignition

Mikesrv6:
I attach an information about mercury engine.
Pay attention in Suppression Diode because you must touch the wire with your fingers in order to find the diode.
Some engines doesn?t have this diode
Change both , you don?t need an electrician , you can do it, because you don?t need cut any wire , only unplugged the wires and replace the diode and Voltage regulator.
If you don?t find the suppresion diode , let me know ,I going to take a picture of both equipment , and I will send you .
best regards.
eduardo
 

Attachments

  • Voltage.pdf
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  • Diagram1.pdf
    136.1 KB · Views: 8

mikesvr6

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Re: Mercury 50 elpt efi 4s no ignition

Thank you, only had time to check this now so will head to the boat tomorrow to see. Thanks again
 

mikesvr6

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Mar 2, 2010
Messages
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Re: Mercury 50 elpt efi 4s no ignition

I am really sure what the suppresion diode is, but i have the voltage reg. out now. Is there any way to test it before i bin it? i'll attach a pic of itIMAG0600.jpgIMAG0603.jpg
 

adolfo

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Re: Mercury 50 elpt efi 4s no ignition

I am really sure what the suppresion diode is, but i have the voltage reg. out now. Is there any way to test it before i bin it? i'll attach a pic of itView attachment 152623View attachment 152622


Mike , this is the procedure to check the Regulator , if you have any doubt , please ask me.
Regards
eduardo

Regulator/Rectifier (P/N 854514-1) Diode Test
ANALOG METER
NOTE: Voltage regulator/rectifier specifications are given for informational purposes only.
Use the appropriate troubleshooting techniques previously mentioned to find the faulty
component in the charging system.
BLK = Black
GRY = Gray
RED = Red
YEL = Yellow
YEL
GRY
YEL
RED
BLK
DIODE TEST:
1. Set Ohm meter to R X 10 scale.
2. Connect Red (+) meter lead to RED regulator lead.
3. Connect Black (?) meter lead to either YELLOW regulator lead.
TEST RESULTS:
100 - 400 OHMS
DIODE TEST:
1. Set Ohm meter to R X 1k scale.
2. Connect Black (?) meter lead to RED regulator lead.
3. Connect Red (+) meter lead to YELLOW regulator lead. Test. Then change Red (+) meter
lead to the other YELLOW regulator lead for 2ND test reading.
TEST RESULTS (1ST READING):
20,000 to OHMS
TEST RESULTS (2ND READING):
OHMS (No needle movement)
SCR TEST:
1. Set Ohm meter to R X 1k scale.
2. Connect Red (+) meter lead to regulator case.
3. Connect Black (?) meter lead to one YELLOW regulator lead. Test. Connect Black (?)
meter lead to the other YELLOW lead.
TEST RESULTS (BOTH TESTS):
8,000 - 15,000 OHMS (8k - 15K)
CHARGING & STARTING SYSTEM
90-883065 APRIL 2001 Page 2B-17
TACHOMETER CIRCUIT TEST:
1. Set Ohm meter to R X 1k scale.
2. Connect Red (+) meter lead to GREY regulator lead.
3. Connect Black (?) meter lead to regulator case.
TEST RESULTS:
10,000 - 50,000 OHMS (10k - 50k)
 

mikesvr6

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Mar 2, 2010
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Re: Mercury 50 elpt efi 4s no ignition

Thansk again for the help eduardo. with the first diode test i got nothing, the second gave ~450 first wire and the same for second one. scr test gave ~46000. they seem far from the required anyway. does this look like what yours did? I found the suppressor diode and was wondering can i test that or is it definitely gone? thanks
 

adolfo

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Apr 6, 2012
Messages
12
Re: Mercury 50 elpt efi 4s no ignition

I am really sure what the suppresion diode is, but i have the voltage reg. out now. Is there any way to test it before i bin it? i'll attach a pic of itView attachment 152623View attachment 152622

Mike ;
more information about the measurement Voltage regulator

DIODE TEST:
1. Set meter to .
2. Connect Black (–) meter lead to RED regulator lead.
3. Connect Red (+) meter lead to either YELLOW regulator lead.
TEST RESULTS:
0.4-0.8 V
DIODE TEST:
1. Set meter to .
2. Connect Red (+) meter lead to RED regulator lead.
3. Connect Black (–) meter lead to either YELLOW regulator lead.
TEST RESULTS (1ST READING):
8 or OUCH or OL
SCR TEST:
1. Set meter to .
2. Connect Black (–) meter lead to regulator case.
3. Connect Red (+) meter lead to either YELLOW regulator lead.
TEST RESULTS (BOTH TESTS):
1.5 V - 8 or OUCH or OL
 

jerryski59

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Aug 9, 2011
Messages
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Re: Mercury 50 elpt efi 4s no ignition

Did the same thing in the dark trim works fine every time I try to start blows the fuse . just checking what to replace to get my motor running again ( same Model) 2007
 
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Fun Times

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Re: Mercury 50 elpt efi 4s no ignition

Did the same thing in the dark trim works fine every time I try to start blows the fuse . just checking what to replace to get my motor running again ( same Model) 2007
Hi there jerryski59, welcome to iboats!:) As we realize it may have been easier for you to tag your question onto the end of this old thread since your question may pertain to some of the conversation referenced above. Unfortunately it may not make it easier for all of our helpful members that like to log on from time to time and answer a few quick questions when possible before moving onto something else in their life. As their time may be short to try and help, they may not have notice the original posters first date posted and answer the first question at the top before reading any of the other post only to come to find out later that the OP has typically already been helped to the best of our best abilities and they may be long gone by now and in turn your question may get skipped altogether being near the bottom. So it is iboats recommendation to always start a new thread of your own in order to achieve the best over all results for your question. Thank you and good luck with you getting your engine running back to normal.:) Also for future together reference, Please see our announcement linked right here, Announcements - Mercruiser I/O & Inboard Engines & Outdrives
 
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