2006 Mercury optimax 150 no power to ignition or fuel pump

[Matt musky]

Ok so I have a 2006 mercury optimax 150 and coming out of winter storage I can't get it started . Stored it away in mint condition. ! Anyways so I have no power going into the fuses for the fuel pump or ignition coils. Kill switch looks good . Hear one beep upon key on and one beep as it's cranking . It just keeps cranking away but no spark. I swapped the main power relay with the trim relay and no luck. I did notice some water in the relay harness which was weird. Battery cranks the motor fast and seems strong . Any suggestions ?

 

[alldodge]

Kill switch looks good

Howdy

Get a volt meter and measure the voltage on each side of the kill switch. Switch might look good but may not make contact

 

[Matt musky]

Hi
I have 12v to one side of the relay . It seems like the coil side of the relay is not getting voltage . Does the Kill switch control that circuit? With the kill switch off I do not get a beep with a key turn. So I assumed it was working but I will check that asap . Thank you

 

[alldodge]

In most cases (not an OB guy) the kill switch keeps 12V from going to energize circuits. For Mercury/Mercruiser this is the purple wire. Power goes to the key switch, then from the ON or Ignition side (purple wire) it goes to the kill switch, then to the helm gauges and the motor.

Now there will be 12V on the relay power side, but it needs 12V on the coil of the relay side. In the below pic, there would be 12V on one side of pin 30 or 87, but there would not be any power to 85 or 86 so long as the kill switch was open.



Check if there is 12V going to the key switch, if not, there is a 20 amp fuse in line going to the switch

 

[Matt musky]

Ok I will check it as soon as it stops raining ! Thanks
Alldodge !!

 

[Matt musky]

Hi
Ok so I have power in the purple wire at the motor . I only get 4.4 volts on the coil when key is on . If I ground one side of my meter then I get 12v on coil. Do you think I have a bad ground ? They are all clean and tight. I checked the all purple wire at the disconnect in the motor and it had 13.8 at key on . I'm stumped ?

 

[alldodge]

Hi
Ok so I have power in the purple wire at the motor . I only get 4.4 volts on the coil when key is on . If I ground one side of my meter then I get 12v on coil. Do you think I have a bad ground ? They are all clean and tight. I checked the all purple wire at the disconnect in the motor and it had 13.8 at key on . I'm stumped ?

Your statement is making me scratch my head. When using a volt meter the black probe is placed on a ground to read volts. If you just put the red problem on and don't ground the black, your not getting a complete circuit reading.

In any case your getting power to the coil, which means your kill switch is ok and also the key switch contact. Now we need to figure out why your not getting spark.

I'm an inboard guy and was hoping with my comments the outboard guys would show up.

Look at another site and found the Optimax needs a lot of cranking amps to fire up, minimum of 1000cca. Also don't use jumper cables or booster box, because they won't supply enough amps. The motor has fuses

fuses located on the stbd side of the motor back near the head about 1/3rd of the way up in a plastic cover screwed to the block.

If these fuses are good, then there is a crankshaft position sensor (CPS) at the base of the flywheel which tells the ECM to fire the plugs. Remove the connector and reinstall after checking contacts. When key is turned to ON the fuel pump should run for a few seconds. Without a code reader were in the dark for the most part. So if the pump comes on, the CPS connecter is good, fuses are good, then more then likely its either the CPS or the ECM. Only way to find out is with a code reader

 

[Matt musky]

I have no power to the coil of the master power relay . If I jump the relay I can get power to the fuses and the fuel pump. I have one side of the coil with 12v to ground but I have nothing if I test both leads to coil with key on. So something is preventing the coil from getting a negitive to close the relay and start the motor any thoughts ?

 

[Rodney Williams]

Ok, here we go!!! I also have a 2006 150 Opti and just went through the same thing. Here's a list of things to check and what I found out in the process:
1. Optimax engines require a lot of power. They need minimum of 1000 cca of power. I have twin 1000cca batteries
2. Again, make sure all fuses are good.
3. Turn the engine to the run position and listen for the fuel pumps to come on. There are two electric pumps and one mechanical pump. The electric pump that is external is a low pressure pump. It should energize when the key is turned on. You can also feel it running when the key is turned on also. The high pressure pump is in the vapor separator (big aluminum tank that the water separator is mounted on). Get someone to turn the key to the run position and feel if the pump is running. If pumps power up proceed to next step.
4. Check and clean all grounds on the coils. (There are several grounds and multiple wire sharing common grounds).
5. Check the fuel pressure at the Schrader valve on the fuel rail. Should be aprox 90 psi.
6. Check the air pressure at the Schrader valve on the Air rail while someone is cranking the engine. IT too should be at least 90 psi or equal to the fuel pressure.
7. There is a crankshaft sensor on the rear port side of the engine looking at the engine from the front. (Aprox $80 when I checked) There are two wires on the sensor. Using an ohm meter check the resistance between the wires. It should be 150-300 ohms according to the service manual. If it is open or reading more than 300 ohms replace the crankshaft sensor. Use a spark tester to check for spark as you attempt to start engine. There should be spark at all plugs now.
8. If you don't remember the last time the plugs were changed go ahead and replace the sparkplugs while you're at it. You will pay $20+ each for these plugs if you order them or get them from a marine parts supplier. Don't waste your money there. These are NGK Iridium tipped Lazer plugs. Replace only with these plugs!!!!!!!! Save your money and go to Advance Auto, Autozone or any other parts house to buy these plugs and save at least 50%!!!!!!!!!!!!! They are the identical plugs used in the new V-6 Jeeps. Don't believe me?? have them run the plug number and see what these exact plugs fit. Your choice, spend $120 for the plugs at the marina/shop or spend $60 at the auto parts store for the identical sparkplug. (I was surfing the intra web one night and discovered this by accident). Let me know what you find out. Hope this helps.