70's Model 40HP Mercury Stator Compatability

I recently was given a 73 mercury 402 40hp outboard to replace the blown Johnson that came with the boat I just bought. Lucky me huh. Well the wiring has turned to dust and I am wondering what is the best place to find a stator and wiring harness? I need the motor side of the big plugin. My REAL question is how many models have those same parts. It looks like about any mercury from that era has the same style plug. What about the stator on a model like that? If anyone knows how big of a net I can cast for my search I would greatly appreciate it.

BTW- I have popped into this forum to search questions in the past and I have to say, as a casual reader, there are some of the most helpful people on here. I belong to woodworking and other forums where everybody just brags about their stuff and offers little real help. There must be something in the water.

Thanks in advance.

Re: 73 Mercury 402 40HP

Re: 73 Mercury 402 40HP

I have repaired the wiring on alot of these 70's models, all now suffer from the dreaded wire rot, thanks to mercury using rubber covered wires instead of PVC insulation. Fixing the problem if you want to go back with NEW parts is expensive. You can get a new male engine plug from CDI Electronics online (www.cdielectronics.com) but the plug is almost $200! They also sell replacement stator coils, also about $200! I have saved some stator coils by being very careful with bending the wires especially where they enter the coil stator, first I cut the wires close to the stator coil leaving enough for a butt splice connector then I check resistance per CDI's troubleshooting charts, if OK, I crimp on uninsulated butt splices on to the cut wires then slide on short pieces of heat shrink, the thick type with the glue inside of it, then I shrink the tubing down. After this, I squirt a modest amount of urethane PL flashing adhesive (http://www.stickwithpl.com/Products.aspx?ID=Polyurethane-Roof-Flashing-Sealant ) to the area around the stator where the wires enter it and some on the short pieces of wire with the butt splices. I smooth this out and let it dry completely (24 Hrs.), this stuff dries tuff and makes an excellent "strain relief" to this area, then I crimp on my new PVC insulated wire, I use MTW type wire which is (machine tool wire, and oil resistant), it is limp and easy to harness and you can get from your local electrical supply house. Just doing this saves me $200! I also do this to many switchbox's that have wire leads coming from them and the male plugs that attach to the lower cowling.

Re: 73 Mercury 402 40HP

Re: 73 Mercury 402 40HP

Unfortunately the stator wires have already sheared off right as they come through the grommet. There is NOTHING left to attach too. I can get by without the plug if I have too since I could just direct wire everything through the cowling. I found a stator off a '70 40hp mercury that is in useable shape and I am wondering if it will work or what models/year range I can look though. Thanks.

Re: 73 Mercury 402 40HP

Re: 73 Mercury 402 40HP

jjbarnes said:

Unfortunately the stator wires have already sheared off right as they come through the grommet. There is NOTHING left to attach too. I can get by without the plug if I have too since I could just direct wire everything through the cowling. I found a stator off a '70 40hp mercury that is in useable shape and I am wondering if it will work or what models/year range I can look though. Thanks.

Click to expand...

Since your stator is kaput any way, you can dig out the rubber grommet and expose another 1/2 inch of wire, which, if it is in good shape you can solder new leads to. Heat shrink the joints and re pot in silicone rtv, black.

Re: 73 Mercury 402 40HP

Re: 73 Mercury 402 40HP

I wasn't sure if taking the grommet out was possible. I tried pulling on it a little but with no results. And by tore off at the grommet I mean the wires are already about half way down inside it. I was going to take one more crack at it this evening by carefully grinding away the little retainer around the grommet and see what I could get but I don't hold much hope.

Re: 70's Model Mercury Stator Compatability

Re: 70's Model Mercury Stator Compatability

I went here >>>>>>>>>>> http://www.marineengine.com/ <<<<<<<<for all my electrical replacement parts and saved me over $200 dollars! everywhere else had significantly higher prices.

for the same reason as you, I replaced my Stator, Trigger, rectifier, water impeller kit, miscellaneous gaskets, and a fuel line fitting for $375 w/ shipping!
if I couldnt find it I used Crowleymarine.com for part numbers and search marineengine.com And found everything.

The only thing I found that I was able to really save money DIYing was my wiring harness. Heres pic of how I cut it up and soldered new wires...

Re: 70's Model 40HP Mercury Stator Compatability

Nice work on the harness, very clean and professional looking once it was done. After looking at mine more closely last night I think if I cut back part of the plug I can get about 1-1.5" of good wire and make splices off that. I should be able to tackle that and if not I'll run the wires about a foot outside the motor and throw away the original plug entirely and make my own. Lest ye forget what a true hillbilly would do, I R 1

The stator is still up in the air though. marineengine.com has it listed pretty high at over $200. iboats has an aftermarket for about $195. I saw a list of resistance and voltages for merc stators and looked at the '70-71 models vs. the '72-81 and they look virtually identical. The numbers are a little different but they use some common parts like the rectifier and I think the trigger. Does anyone know if the 174-4424 stator ('70-71 model) can actually replace the 174-5255 ('72-81 model)? I have a line on one fairly cheap but don't want to throw money away on something that won't work. The guys on the internet who has it doesn't know for sure either.

Re: 70's Model 40HP Mercury Stator Compatability

jjbarnes, I found this site for parts, http://www.boats.net/ good prices.

Devin