Two wires running from stator to rectifier prevent my engine from starting?

[camojro]

I just scooped up a 74 850 thunderbird for a great deal. It's been sitting for years and the two wires from the stator to the recitfier are completely corroded and even slightly making contact at the stator exit. From my understanding these just provide a charge back to the battery. I obviously need to replace the stator, but before making the investment I would love to see if the engine may start. I am going to check for spark tomorrow and fuel supply tomorrow. Just figured I'd ask in preparation if someone knew. Thank you!

 

[Texasmark]

Those wires are approximately a short if measured between them and infinity between a wire and ground. That's a good start as long as you don't smell or see the results of smoke. They are as you say, just the AC input to your rectifier/regulator module. Your triggers and Capacitor discharge ignition operating voltage come from different coils in the stator.

Mounting position on the block vs flywheel position is only important for triggers so yes you need to get it lined up correctly.

I bought that engine new, had the blue, silver, red straight line bands the pointed down at the rear of the black cowl whatever year that was....problably late '70s. One of my finest engines. Never had a bit of a problem. Was an excellent cold weather starter. Very quiet.

 

[Chris1956]

A 1974 Merc 850 should have distributor ignition. If so, the stator is two wire and only serves to charge the battery. I would disconnect the stator from the rectifier for test purposes. Your rectifier could still be good, so why ruin it?

The battery-driven CDI ignition is powered by the battery. A lot of those motors have really bad wiring harnesses at this point. If you try to start is, you could ruin some expensive ignition components.

I would oil the cylinders and use some jumper cables directly to the starter to take a compression test. If this test is good, you might purchase a new engine wiring harness (unless it is good) and proceed to test spark.

 

[Texasmark]

A 1974 Merc 850 should have distributor ignition. If so, the stator is two wire and only serves to charge the battery. I would disconnect the stator from the rectifier for test purposes. Your rectifier could still be good, so why ruin it?

The battery-driven CDI ignition is powered by the battery. A lot of those motors have really bad wiring harnesses at this point. If you try to start is, you could ruin some expensive ignition components.

I would oil the cylinders and use some jumper cables directly to the starter to take a compression test. If this test is good, you might purchase a new engine wiring harness (unless it is good) and proceed to test spark.

OOps......I Lied! Disinformation! Sorry bout that. I was thinking the later models like i have.

 

[Chris1956]

Mark, I believe a 1975 Merc 850 is the first one with ADI. You were close.....