50 Hp Mercury Ignition Switch Diagram

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How to hotwire/jumper Merc keyswitch?

Well, the boat is slated to get wet on Thursday. I'm trying to get some hose time on it, but I lost my keys...actually the whole bag with the keys, plugs, plug wrench etc.
Anyway, I have the key switch out and here are the wire colors:

Red - I assume 12v in
purple - ?
yellow/red - goes to neutral switch then to the back
black/yellow - ?
yellow/black - ?
black - ?

What do I have to jumper the red to for "run"? Which is "start"? Which is "choke"?

Thanks!

Keith-
just dissconnect the control box (big plug) at the motor and then jump out the selinoid (spelling?) or just run power striat to the starter while the condtol box is still unplugged...
youll still have throttle and so on at the helm just that youll have to choke it to shut it down

Quartershot T-3R 15" 3.5L E-Tec 1.62 Sportmaster
So there is nothing that has to be jumpered to make it run? Just disconnect the control harness, jump the starter solenoid and that's it?
What about the enricher circuit...where can I jump that?

Keith-
is it efi?
what an enricher? aint it like a primer?

Quartershot T-3R 15" 3.5L E-Tec 1.62 Sportmaster
Yes, EFI. Enricher = primer/choke whatever.

Keith-
Keith

ECU's are VERY expensive I would wait and get either a key or new key switch harness , I know your anioux but it ain't worth it ! Pop your ECU and you'll be kicking yourself in the keester !

Jay @ JSRE
ahh ok
im not real familiar wit mercs but i know youll have to jump it out from the motor because the control box will have no electronical control over the engine after you unplug it

so if you'll have to feed the primer power through other means be creative lol!

hope this helps sorry i cant give you wire by wire directions but this is wut i know good luck dont get shocked!

jays got a good point! im thinking carbed..

Last edited by baja200merk; 05-31-2004 at 07:05 PM.

Quartershot T-3R 15" 3.5L E-Tec 1.62 Sportmaster
Guess whos eliminating that key switch with push buttons?
Red - I assume 12v in
battery power
purple - ? Key switched power for acc.
yellow/red - goes to neutral switch then to the back goes to starter-crank
black/yellow - ? This is your on and off- open for run.
black - ? This is your off. Black/yellow grounds the switch box for off.

yellow/black - ? fuel enrichment which isn't always hooked up on EFI

So red should go to purple so your gauges work.
Jumper yellow/red for starter to run. Sparky so don't melt nuthin.
Black/yellow stays open.

Black/yellow goes to black to shut down, remember to disconnect the purple from the red.

Remember this shuts down like shorting out the spark plug on a lawn mower, you let go too early and it can keep running. Turn the prop or flywheel and it can start.
sowmthing else
Your safety switch kill switch operates through the key switch. If you don't have it hooked up this switch won't work. It too grounds the switch box wire rather than the ignition turned to 'off'
If you do hot wire this check that wire out.

Last edited by Techno; 05-31-2004 at 07:19 PM.

'90 STV
'96 260
under construction

for far too long
Yes, I am anxious. It ran last Thursday for a bit, but needs more hose time. Today is the last day I can until it hits the water.
I have tried it with the harness connected - which doesn't work since the key is off. Also tried it with the harness disconnected...also didn't start. There must be a "run" circuit looking for 12v to allow it to run. I'm thinking it's the yellow/red wire that goes through the neutral safety switch.

Keith-
Thanks techno...if I'm reading you correctly, the yellow/red is the START lead, not the run, so if I'm manually engaging the starter with a bump button, I don't need that.
It spins over but won't start with the harness disconnected.

Keith-
Originally posted by Techno
Your safety switch kill switch operates through the key switch. If you don't have it hooked up this switch won't work. It too grounds the switch box wire rather than the ignition turned to 'off'
If you do hot wire this check that wire out.

There were three black wires off one side of the "safety switch". One black/yellow wire off the other side. Do I need to ground those all together? Meaning that switch in the run position is normally closed and goes to ground?

Last edited by STV_Keith; 05-31-2004 at 07:29 PM.

Keith-
I don't know. The safety switch does the same thing as the ignition switch. I mentioned it in case you were depending on this switch when it might not be active. If you started it on the hose and yank the lanyard and it shuts off then you just traced it the easiest way.
BUT

If your only running on the hose then disconnect the black/yellow off the swiitch box. hook another wire to this post This way you can shut it off and not ruin the stud post from arcing.
This wire is grounded to shut it off.

I
think disconnecting the harness kills the ecu. Remember it has power at all times. No power no runn.
To start and run >that hanging wire is open. You bump the starter and it starts.
To shut off you short the hanging wire to ground, something that won't matter. No need to disconnect anything else.
It may arc and arcing melts stuff. Just like not using a bump starter and using a wrench instead will melt the terminals.

'90 STV
'96 260
under construction

for far too long
" Jig Rig " Wiring

Keith I have witnessed SOOO many ignition and ECU failures resulting in blown motors and torn up parts due to inadiquit or improper wiring on EFI engines , fix the thing correctly when it is done with a key and the OEM in tact harness your safe with the "jig rig" way you have no security at the lake any ya ho can jump in your boat and crank it ,also you jeprodise your ECU to a spike and a possible failure! Mercury engininered that harness and key switch for a reason with the correct wiring sizes and my bet is THEY knew what THEY were doing.........
A PCU is $1000.00 + and a Mercury ECU even more , think about it !

Off my soap box now, your motor and your money !

" when doing a job large or small do it right ( correctly) or not at all "

My moto and
My opinion

Jay @ JSRE
Yeah, I bagged the idea. I'll get it lit again tonight with Kevin's harness. I'll have keys for mine tomorrow.
FYI though, this was just to get the thing running on the hose. We are fully rigging the boat and getting a new key tomorrow.

Keith-
Ya but....
If he does kill the ecu good reason for the PCU.
Doh!
(dual meanings)

'90 STV
'96 260
under construction

for far too long