1973 85 hp Merc,, Lost spark while idleing

[nomorefords]

Re: 1973 85 hp Merc,, Lost spark while idleing

Thanks USS,, the diagram is a huge help,! The 2 whites i mentioned apon closer look,one is for sure white, the other must be yellow badly faded, just a slight difference in shade. I do have the silnoid wires crossed.

I see the (salmon peach) color goes to the off position on the key and ends at the connect. can I just tape it off,, or does it need a home?

remember,, the connectors are gone, any unions that were made in it, I now have to compensate for. such as the 2 reds and 2 blacks that join on the external plug any advise on those?

Thanks again!

 

[nomorefords]

Re: 1973 85 hp Merc,, Lost spark while idleing

I reversed the silnoid wires,, now i have a click in the switchbox,,or coil when i turn the key ,that is what it did before and i'm sure is normal. I still cant get the starter to inguage

 

[usskydvr]

Re: 1973 85 hp Merc,, Lost spark while idleing

The salmon can be taped off. With the key off , using a car jumper cable can you get the starter to spin if you connect the Pos on the battery directly to the Starter? If that works you probably have a bad solenoid. If that doesn't work then a bad starter. (p.s. use the jumper cable to ground the battery directly to the starter mounting frame, just to ensure you have a good ground)

 

[nomorefords]

Re: 1973 85 hp Merc,, Lost spark while idleing

I replaced the silnoid,, starter spins just fine when jumped. The starter worked before I removed connectors and wired direct.

Heres the real funny thing I just don't get

with plugs out of motor but in wires and grounded and a small jump wire, 1 end solidly connected to red on switchbox the other end of it free.

If I take the free end and rub it over the white connector on the switchbox while spinning the flywheel by hand I get a nice hot spark on each plug,, 1 at a time,

If I stop rubbing and hold it tight to white connector spark stops. If I hardwire the red to white I get no spark,,, only when im rubbing the connection against eachother

One more thing that has my attention is the black that leaves the starter post of the silnoid (small one) trace that back to the connector, on the external side,, it joins heavy black of battery and a black that goes to control box,, also says ground to cowl

See diagram provided by my friend USSskdvr

Thanks
This only happends with the boat key in off position.

Weak coil? trigger? If the stater was bad would I get the spark at all?

 

[usskydvr]

Re: 1973 85 hp Merc,, Lost spark while idleing

When you either hard connect or rub the other end of the Red connected wire to the white switchbox terminal you are effectively turning on the ignition. Depending on where the dist trigger is aligned you may get a spark

What you are doing is NOT an accurate test.

Test the switch box by:
1. Rotate to #1 plug (or any other plug)
2. Remove all three wires (Black, Brown, White) that go to the Dist from the switchbox
3. Jumper the (now empty terminals on the switchbox) Brown to the White
4.Turn ignition on
5. Verify you have minimum 12v on both the Red and White (on the same side of the switchbox, not the Dist side).
6. Flash the Black (empty terminal on the switchbox,Dist side) to Gnd.
Do not HOLD the Black to Gnd, only flash it. Each time you do this you should get a spark.
This test effectively duplicates the action of the trigger in the Dist.

The small black on the solenoid SHOULD go the the Big Black that goes to the Battery and the Cowl ground