1991 Mercury 175XRi - nothing happens when I attempt to start the engine

[JonM]

I recently had another thread here, and thought my problems were behind me. The original issue seemed to be fixed by replacing the Trim Down solenoid. What I didn't know at the time of that repair was that the power wire at the remote throttle was worn to the point of the copper wires being exposed. The trim down was working find for the few few short trips on the water, and then a few days later while heading out of our bay at a slow speed, the motor quit and wouldn't start, as in nothing happened when I turn the key - no click, no engine turning over, nothing. At this point, the trim down or up didn't work either.

I suspected some type of electrical issue, and then found the pinch-damaged power wire at the remote throttle at the console. I also pulled the cowling off and found 2 glass cylinder type inline fuses, 20 amps each. I replaced both of those fuses, and now the trim up works again, but attempting to start the motor still has nothing happen.

It seems like this damaged wire may have blown out my Trim Down solenoid again, and also blown a fuse other than the 2 I replaced, that may explain why the motor does nothing when I attempt to start it.

After replacing these 2 fuses, my bilge pumps and trim down now work again, so I don't think it's battery related for the not starting issue.

I will attach pics of the 2 fuses I replaced under the cowling, and hope someone can point me to other fuses that may be an issue. I looked under the console where the ignition wires are and I don't see any bad or disconnected wires, and I don't see any fuses there either.

[Merc 2.5]

A remote starter button or U can cross solenoid to c if start will bump over to see if n switch, but those should b only fuses , 1 was trim other is for main harness , all wires hooked up at solenoid?

[JonM]

Thanks, I'm waiting for my Remote Starter to be shipped, in the meantime what do you think of this plan?

I'm planning to test the Solenoid by connecting a pair of jumper cables to my starting battery by connecting the + battery cable to the incoming + connection on the Solenoid (top red circle in my diagram), and then connect the - battery cable to a bolt on the engine block, and then finally disconnect the start wire (Yellow with Red Stripe) from the Solenoid and touch it to the + battery cable connection on the Solenoid. I think this will tell me if the Solenoid is the issue or not, correct?

I was also planning on doing another test where the + battery cable connects directly to the Starter's + connection (the bottom red circle in my diagram), and then ground the - battery cable to a bolt on the engine block to see if that has the motor attempt to start.

[tlwjkw]

have you got a 12v test light similar to this? if not get one.

[JonM]

Yep, I have a couple of those. I take it you're saying to check for a circuit at the Solenoid, and then next at the Starter?


Thanks

[tlwjkw]

thats all tha tool ya need if battery and battery cables goin ta motor are all good... ANY and ALL red wires big and small should have 12v on 'em at ALL times no mater if key is on or not.. if not find out why.. key to start, yellow/red on sol. should come hot.. big pole on sol. going to starter should come hot.. starter should turn over..

tilt n trim should have 12v 24/7 to controls (all t n t switches) along with battery power to big post on sol's... key does nothing to it... again red is always hot..

one thing you don't mention is grounds?.. clean and check every SOLID BLACK everywhere, on anything.. big and small..

[JonM]

I tested all 4 red wires coming into the Starter Solenoid, and all 4 lit the lamp.

I then tested the Yellow\Red wire connection to the Starter Solenoid, I believe this is the key switch wire. I had my wife turn the key to start 2 or 3 times and hold it there while I had the test probe on this connection and we couldn't get the lamp to light.

Does this prove it's an issue for the Key Switch wire, between the console and the Starter Solenoid?


Thanks

[tlwjkw]

if you did not get a light on yellow/red to ground when key is on start you have a problem with key switch more than likely.. first you need to verify that tha small red that feeds key switch is a constant hot "at tha switch". (one of tha four ya tested)

make a short jumper from any wire ya have.. jump from big positive battery post on start solenoid to yellow/red post on solenoid.. this should cause solenoid to close and starter to turn.. if it doesn't, jus for ****s n giggles, check tha small black (ground) on solenoid for good connection..

[JonM]

I used a 12ga jumper wire from the Yellow\Red wire connection on the Starter Solenoid to the main incoming positive positive post on the Start Solenoid, and the when I did so the Starter shaft up to the flywheel began to rotate.

With this being the case, should I focus on the console and the Yellow\Red wire and connections, and the power wire you mentioned?


Thanks again.

[tlwjkw]

I used a 12ga jumper wire from the Yellow\Red wire connection on the Starter Solenoid to the main incoming positive positive post on the Start Solenoid, and the when I did so the Starter shaft up to the flywheel began to rotate.

With this being the case, should I focus on the console and the Yellow\Red wire and connections, and the power wire you mentioned?


Thanks again.

tells ya tha sol. and starter work.. not gettin' power on tha yellow/red from ign. switch in start position...….

check ALL reds at ign. switch.. should have power at ALL times.. check all grounds (solid black) at ign. switch/harness.. more than likely ya have a bad ign. switch...

[JonM]

I unfastened the key switch\ignition. Can I test the 2 red power wires, and the 2 black ground wires with the same 12v lightbulb tester?

There is also a 3rd red wire that splices into a purple wire, I take it that should be hot at all times also.

I'll attach a few pics.

It looks like I will have to pierce through the wire shielding or possibly get the prong of the tester onto the wire where it connects the key switch housing.



Thanks