Logo

1978 mercury 402 wiring

needymerc31

New member
"Hello me again..
Thanks for


"Hello me again..
Thanks for the wire link'er JB, is a good one. I definately am no electrician. This may be asking alot, but I have to try- So here goes nothin..

The old plug harness (1966-merc650) has (6) wires. Red, Black, Yellow, White, Green, Brown.
OK now,
The new plug has 12 wires, 4 of which re-surface at the hind end of the actual male plug to be connected. This was a 8-pin male to female 2ft extension harness. I bought and cut in half to gain the male plug end I needed to make engine connection.

These (12) wires are: Red, Black, Brown, Green, Purple, Yellow/Black, Yellow/Red, Black/Yellow, Brown/White, Brown/Black, Blue/White, & Green/White.

The colors that resurface on opposite end next to plug end are: Brown, Brown/White, Green/White, & Blue/White.

Control box(6 wires)---------wire---------6 ends.

(12 wires)------wire--------(4wires & 8pin male) to make engine connect..



If anyone knows please help. As I hope I can accomplish this with the new plug end. I possibly need the whole harness front to back?? Please say no, ($$$). If so then, so be it..($next week!) Many thanks to anyone that has the time or patience for this.

You are good people..

Brian-
sorry this may be posted twice-"
 
"[url=""]http://www.maxrules.c

"http://www.maxrules.com/oldmercs/Wiring/1966ona/29.jpg"
http://www.maxrules.com/oldmercs/Wiring/1966ona/31.jpg"

above are 2 links to the 1966 mercs, with different serial numbers. the problem is they both had a distributor and coil assemby for ign. From this I gather the coil needs power from the battery to start, the 402 model doesn't need power to start, only to work the choke and engauge the starter solenoid. Long story short, your key switch will be all messed up. It wont be sending power to right cicuit at the right time, or it will be sending power all the time.
I can tell you what the 402 needs and what the color codes are but I don't think the 1966 switch is going to work. I'm thinking ebay. Have you tried the control cables yet, will they work."
 
"<[img]"http://www.marineengin

"
sad.gif

Red to Red
Black to Black
old Yellow to newer yellow/red (start)
newer Purple to older white (ign) (If it needs power)
Old Brown to newer grey (tach)
Red/yellow to old grey (choke)??? maybe green???

If it needs ground to stop than the newer black/yellow will go ?somewhere, maybe orange??"
 
Thank you for the quick respon

Thank you for the quick responses.

I don't have a tach in the boat & I think that these controls are without a tach hook-up.
The control cables fit snuggly and seem to be working exc.. will try wiring today and e-rep.
 
"<[img]"http://www.marineengin

"
blush.gif
, I was 2 when the 66 model came out. Try what Bandit said, I just think it would be safer to change to something newer than smoke the powerpack, although I'm sure he has the skills to make it work."
 
"OK, on JB's suggestion, I

"OK, on JB's suggestion, I hooked up 4 of the 6 old wires, black-black(neg), red/red(pos+), old yellow to new yellow/red (start), old grey to new yellow black(choke). last two old wires-white & brown did not yet find a home, and not sure what they control?

All seems to work to my suprise, started right up ran good, forward,reverse, etc.. Could NOT shut off though.
Could I maybe (a cheap fix but) put a toggle switch on a specific engine wire to shut off?? Or will this set up turn bad/fowl on me? Like something I am not immed. seeing that also needs to be hooked up for proper op.

Upon starting, as expected some smoke came out the lower end/exhaust from sitting for a few years.

After about 1-1 1/2 min I reallized the smoke was not just from old gas or from clearing, the water is not coming through, and was heating up, some smoke came from the exhaust manifold. Doesn't appear that I hurt anything, but any suggestions here? I know this motor was completely rebuilt 3-5 years ago, but I have read (here) that impellers and water pumps are tempermental items. Could this at all be related to the current wiring not being correct, or is it strictly mechanical?

If h20 pump and impellar is needed, it would be a great help if I could get a link, and a part number to be sure of.

Thanks for the help all, gggreatly appreciated.

-Brian"
 
"bl/y wire to ground to kill t

"bl/y wire to ground to kill the ign, maybe it hooks to the brn wire I don't know, but a volt/ohm meter could tell you if its safe.
water should flow out the center of the prop and the out the tell tale. Waterpump should go every 2 years. There are seals in the pump that should go every 4 years. There is a seal at the base of the engine that melts when it gets hot from exhaust and from lack of water, its tough to get to.
Water pump removal, start with controls in neutral, remove 2 5/8 nuts at front of lower unit/ fins. Mark and remove trim tab, 7/16 12 point socket from above, look under trim tab, there are 2 more nuts 9/16 I think. 1 is hidden unless the tab is removed. lower unit should slide down. Remove 3 7/16 nuts from plastic housing and pull up over drive shaft. Remove old pump. Install new pump on keyway, lube with vasoline or grease. Force plastic housing over new pump while turning drive shaft clockwise. Install new water slinger on shaft, grease crankshaft splines lightly. Re-install lower, verify lower unit is still in neutral by spinning prop freely. wiggle flywheel to align spines. Make shur water tube goes in pump on the way up. Warning, remove plugs if your engine could still start. impellar looks like 18-3007, need serial number
http://www.marineengine.com/parts/sierra_marine/catalog.html?[url]http://www.marineen gine.com/parts/sierra_marine/mercury_mariner.html[/url]"
 
"Thanks a heap JB, Will start

"Thanks a heap JB, Will start tomorrow morning.
(near 100 degrees in the shade today in the northneast!!)

The serial number is 4862188. Saw on chart, you are right 18-3007, so I need a whole kit? or the kit plus other parts/seals?

Maybe I need to investigate first, or just get all necessary & suspect/upkeep parts, as I want to do it right the first time, what would u suggest...

-Brian"
 
"you can pick up just the impe

"you can pick up just the impellar for now, thats a great price by the way, normal is about $18. Shipping might be a break even. I'm in St.louis, hot and sticky with flood water coming from the north. Should've been on the water in April, still can't go. Might be a couple extra parts on the drive shaft I didn't mention. The newer models add a couple of seals, trying to keep the water out and grease in. Look here for newer model ( gear housing-drive shaft)
http://www.usboatsupply.com/Mercury_Mercruiser_Parts_Catalog3a.php?mc=01&ms=3170 &si=673"
 
Back
Top