Blue Band Mercury 850 Serial Number

[Redhot]

Project is coming along well. I can't seem to find the correct internal wiring harness so I was going to hard wire it. However, my question is there are 7 wires on the external wiring harness going into the engine. Only 6 going into the engine. What happens to the white wire? Where does it go? Any help? Thanks guys.

 

[Chris1956]

The white wire is not used on ADI ignition systems. The engine harness must be unique to the ADI or Battery CDI ignitions. The boat harness can be common to both, hence the extra wire.

 

[Redhot]

2 quick wiring questions. I apparently didn't take good enough notes. On the rectifier, yellow and red wires go on the 'diagonal' studs, red on the 'lone' stud, and brown on either one of the yellow/red studs? Does not matter which one, correct? Second, orange wire coming off of mercury switch to terminal block, that has 2 studs. Orange comes from same stud to switch box, and third orange from wiring harness, all on same stud or can I/do I use both studs? Does it matter? Thanks all.

 

[Chris1956]

Your description of the rectifier wiring is correct. The brown wire provided the tach signal from the stator and either yellow/red wire may be used. Just so you know, the rectifier is a bridge of 4 diodes. Any or all of them can fail leading to low charging or even battery discharge and possible ign failure.

Orange wire is ign killer wire. The Mercury switch grounds the orange wire if the motor is tilted up, as if you forgot to put it down, or it hit something and popped up. The mercury switch grounds the ign circuit exactly the same way the ign switch does. Sometimes the mercury switches fail closed, killing spark.

 

[Redhot]

Another quick question. You all are awesome by the way. Putting flywheel back on and it doesn't seem to want to go on all the way. Should assuming that as I tighten the top but down to the 75 lbs, this will set the flywheel properly. I did mark it before I removed, if that matters..... thanks all.

 

[Chris1956]

The flywheel fits into a "W"-shaped groove in the crankshaft. It only can go on one way. The outer flywheel can go on any of 8 ways. Which are you speaking of?

 

[Redhot]

No Title

This

 

[merc850]

Put it on and turn it around until it drops into place it should have a splined crankshaft with a key.

 

[Redhot]

Yeah I am pretty much just a dumb a$$. I just needed to line it up right. Duh..... So next task is to see why the starter doesn't turn very fast.

 

[Chris1956]

Look for a bulge in the battery cables. That would indicate the copper conductor has rotted out. It can happen well above the battery end. Make sure the connectors on the starter and solenoid are clean. You do have the short black ground cable bolted to the starter, right?

 

[Redhot]

I have a new solenoid all wires are clean and tight However, i am having to jump it with cables since my harness has not come in yet So maybe I am just not getting enough juice through my jumper cables to spin it. Is there another option?

 

[Chris1956]

Jumper cables can be dicey. If you are anxious to crank her, buy some battery cables and wire it direct from motor frame to - post and from starter solenoid to + post. Now jumper the solenoid and see if she cranks.

 

[Redhot]

Chris -

That's the plan now, to get some longer battery cables to get to my batteries. Although looking at the starter, I am assuming this is the original starter; as it has what looks to be a date stamped on it...... 1976. So I may just buy the new starter anyhow.......as well.

 

[Chris1956]

Replacement starters are available from Sierra or ARCO. Remember, they are mounted in rubber, so they must have a good ground cable to the top shroud support.

 

[Redhot]

I will double check my grounds again, etc. But has anyone purchased a starter through that dbelectrical. I assume you get what you pay for at $50......thoughts?

 

[Redhot]

I know this thread started as a serial number hunt but has come this far so I'm just going to keep posting. So I have never heard this motor run. Bought it as a "I am pretty sure it runs" site unseen deal. So I required it all, put on new trigger, was able to splice in new wires in the stator. New rectifier. Spliced in on the mercury switch. New starter. New solenoid. So I put it to new battery cables, primed the ball 2 times and jumped the solenoid. Not thinking it was going to run, I about pooped my pants when this thing took off. As I wasn't putting water to it. I tried to shut it down, but choking it was just making it cough a little but it would not kill it. So I had to test my mercury switch and lifted the sob to get it to die. So things are looking up. I drained the gear lube today which was prolly really old. It was brown, so I assume water intrusion somewhere. Going to pressure test it but am going to replace the seals and be done with it. What is the part number for the lower unit seal kit. While I'm in there I am sure a new impeller is needed so going to replace that as well. Any help on the correct part number there too is appreciated. Any other thoughts or words of wisdom as I have come this far? Thanks to all.

 

[Chris1956]

It is a real PIA to replace the prop seal. I would test it first. The driveshaft seal is usually the one that leaks. That is easy to replace, by just replacing the waterpump base. New impeller, wearplate and 2 gaskets are the correct fix.

 

[Redhot]

Redhot, Your boat wiring harness is probably designed to use on either battery-powered CDI ignitions like the 1976 merc inline six motors have, or the ADI ignition your motor has. The white wire is not used by your engine, but is used by the IL 6 motors. Subsequently, the orange (or salmon color) wire is used by your motor and not by the IL 6 motors.

Hope that helps

So I am going to hardwire the motor to the controls, instead of buying a new wire harness. As I do this, I shall have an extra white wire running back to the engine, but not connected to anything, correct? Thank you!

 

[Chris1956]

Yes, the boat harness likely has the white wire in it. I would cut and insulate it, as your motor does not require it.

 

[Redhot]

Ok, does anyone have a vid or step by step instructions on how to properly rehook up my cables at the outboard. A relatively simple process is now my nemesis. It's hooked up but I have to force it into gear to the point I feel something will break... wasn't like this before I removed them... thoughts? I believe I have something messed up in there. Ugh.