1988 Alpha One 350 engine wiring diagram

[69GTOby]

Anyone have one? I have a mystery wire... It's small gauge, maybe 14-16, near the port riser coming out of the harness with a 6" or so lead. It goes toward the distributor pad, and has a tiny eyelit on the end. It's a little black wire, maybe a ground? Any info or a diag would be great, thanks!

 

[John_S]

Re: 1988 Alpha One 350 engine wiring diagram

The wiring diagrams are in the service manual. Look in the stickies in the Mercruiser forum.

From SM #15, all blacks are grounds. It would be a process of ellimination to find out where it should go, or it might be an extra ground.

 

[Struc]

Re: 1988 Alpha One 350 engine wiring diagram

Is the ignition module mounted on the port riser as well? If so, I beleive it goes on of of those mounting screws.

 

[cyclops2]

Re: 1988 Alpha One 350 engine wiring diagram

Did you remove & forget ?
Or was it always flopping around ?

My 305 has a couple of spares in that area.

 

[69GTOby]

Re: 1988 Alpha One 350 engine wiring diagram

I definitely never removed the wire. It could have shaken itself loose over time. Is that what that is mounted to the port riser, the ignition module? I guess that makes sense. I don't recall seeing any module inside the distributor, and I always wondered what that was on the riser. It's an '88 350 Alpha 1... So, if that is the ign module, and this mystery wire goes to it, could that be responsible for my low vacuum (about 14"Hg) and shaky needle at idle as in my other thread?? Hmmm...

 

[John_S]

Re: 1988 Alpha One 350 engine wiring diagram

If your timing was steady and in spec at idle, it was not causing a low vacuum. The module has a ground path through the exhaust and engine. The black wire would be "insurance".

PS: If you didn't get a SM download, PM me with email address. I can send just the wiring diagram.

 

[Don S]

Re: 1988 Alpha One 350 engine wiring diagram

May be nothing more than an extra wire in the harness. Mercruiser uses the same harness for several engines with different options. If your engine doesn't have that option, it may not use that wire. If your engine doesn't use that option, they won't show the unused wire in the wiring diagram either.

Here is the wiring diagram for your engine.

 

[Pmccraney]

Re: 1988 Alpha One 350 engine wiring diagram

Further to what don said, mine has a black wire just swinging in the breeze...was for electric choke (which I don't have). I wouldn't sweat it if everything is working and everything that needs grounding is.

 

[69GTOby]

Re: 1988 Alpha One 350 engine wiring diagram

Cool. Thanks guys. Next time I go down to the lake (wont be till winter break) I will check out my Uncle's engine bay. He's got an '88 MerCruiser 350/260 as well, same year, for comparison.

And thanks for the wiring diag, I will save that for future reference!