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  1. K

    2005 4.3 liter Mercruiser ignition trouble

    New temp switch and diode installed and she’s sea worthy again. Popped right off and ran like a top. Thank you everyone for your help!
  2. K

    2005 4.3 liter Mercruiser ignition trouble

    Temp switch has a short. Something I noticed that may have contributed to the confusion the diode in alldodges diagram shows a purple wire and a white wire. My boat seems to match everything else except the diode has a purple/yellow and a white wire.
  3. K

    2005 4.3 liter Mercruiser ignition trouble

    Still may not be the root cause but unplugging the oil pressure sensor isolated that circuit. After that I was just looking for things the purple/purple yellow wire went to. But if the diode runs the TKS sensor sounds like I should check into that as well. I can trace the wire but if you guys...
  4. K

    2005 4.3 liter Mercruiser ignition trouble

    I also checked continuity and found that it was shorted. (Obvious because it was freaking hot) after reading your link I checked it the other way and found continuity in both directions.
  5. K

    2005 4.3 liter Mercruiser ignition trouble

    Because I unplugged it and the boat started. That was my first clue. Plugged it back it and problem came back.
  6. K

    2005 4.3 liter Mercruiser ignition trouble

    It’s this thing
  7. K

    2005 4.3 liter Mercruiser ignition trouble

    Bypassing the pressure switch by jumping across purple/purple yellow caused 4 volts at coil with key on and the fuse in the dash blew before I tried to crank it. Tomorrow I will look for short in purple yellow wire
  8. K

    2005 4.3 liter Mercruiser ignition trouble

    I’m assuming it’s the oil pressure switch located directly about the oil filter? Not sure what else it could be. Purple wire in purple/yellow out. When I disconnected it I get 10 volts at the coil.
  9. K

    2005 4.3 liter Mercruiser ignition trouble

    For the ground I’ve been using the black wire the goes to the cigarette lighter up by the dash and in the engine compartment the black lead stays clamped right on the battery post. Not sure how else I could be doing it wrong. Can see copper on wires by the cannon plug so I know I was making good...
  10. K

    2005 4.3 liter Mercruiser ignition trouble

    If there is something specific you think I should quadruple check I will. You could be on to something. Every test I’ve done was done repeatedly to verify. I make sure I have 12 volts then turn the key and watch it go down to 9 then back up to 12 volts. The digital meter with a stand and clamp...
  11. K

    2005 4.3 liter Mercruiser ignition trouble

    I’m sure. Had meter in the middle of the connection on the jumper wire, 12v down to 9 while cranking. A splice in the purple wire you mean correct? That’s really all I’ve been checking this afternoon.
  12. K

    2005 4.3 liter Mercruiser ignition trouble

    Jumped across B to I. Yes gages light up. No change otherwise. It is not wired incorrectly it’s just an off color purple and it’s the exact same wire color on both sides of the cannon plug.
  13. K

    2005 4.3 liter Mercruiser ignition trouble

    Got a new digital meter with clamp probes. Much better. This is what I learned. I’m losing about 2 volts at red/purple while cranking and another 1v through the switch. (I) terminal and every purple in the dash is at 9 volts while cranking. This is still better than what I have in the engine...
  14. K

    2005 4.3 liter Mercruiser ignition trouble

    How do I test the cannon plug? Will it work with the plug apart? I cannot get behind the panel. I need to take the throttle off. There is no panel, it’s a solid wall
  15. K

    2005 4.3 liter Mercruiser ignition trouble

    This was where my confusion came from. That picture is the old switch before I took anything apart. The wires are connected the same way as when the boat was running. My problem is not the key switch or the wiring.
  16. K

    2005 4.3 liter Mercruiser ignition trouble

    Agree that ‘a’ is irrelevant. Now I know. Summary: 1) followed trouble shooting flow chart to -replace distributor sensor - so I did. Cap/rotor and sensor all replaced. 2) low voltage at +terminal on coil while cranking. 12v with key on. 3) ‘I’ terminal at keyswitch has 12 volts while...
  17. K

    2005 4.3 liter Mercruiser ignition trouble

    That’s when I had my head up my ass and I was checking the wrong purple. I should have said every connection except A gets power when the key is turned to start. Currently have power at the switch (I), not at the coil.
  18. K

    2005 4.3 liter Mercruiser ignition trouble

    Not my boat but it looks very similar to this. Mine has a pad behind it that I guess is for your arm.
  19. K

    2005 4.3 liter Mercruiser ignition trouble

    I bet you are right but I don’t think that will tell me where the problem is. I now know I’m losing power somewhere between the switch and the coil. That kill switch seems awful suspect? Does anyone have info on how to get it out without wrecking it.
  20. K

    2005 4.3 liter Mercruiser ignition trouble

    The switch must kill the accessories to save voltage while starting the engine
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