mercruiser inboard ignition wiring

1993 Mariah

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I have a Mercruiser 3.0 inboard Boat Engine i Need to Know How to Wire the Ignition Switch Which Color Wires Go Where? It Has 4 Prongs four wires one thick orange one red one thin purple and one yellow..any advice. The ignition was recently changed but i think they may have wired it wrong.

Thanks!
 

Bt Doctur

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Re: mercruiser inboard ignition wiring

orange is usually a dash feed fused
red goes to "B",battery lug
purple goes to "I",ignition
yel w/ stripe goes to "S" ,solenoid.
 

1993 Mariah

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Re: mercruiser inboard ignition wiring

First...
When i attempt to start the boat it will turn over but it sounds like the starter keeps trying to start the boat and it then chokes and dies. I am thinking the starter wired as it is, is what is causing this. although, in addition it does not feel like it has a off, on, start type switch. It only feels like it has an off and start. (it does not feel like the swich pops back into the on/run position).

We burned the flywheel up in the starter trying to figure this all out before. We just had it rebuilt and replaced. Don't wanna have to rebuild it again. any ideas on this??


Second...
I think the ignition switch curently in place is a sierra 4 prong switch, at least it looks like it. The dash does have a accessories togle switch.

Just in case the switch does not have a on/run position, which is odd in itself.

Can a three prong ignition switch be used in place of the four prong ignition?
if so where will the fourth wire go??

THANKS AGAIN!!
 
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cr2k

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Re: mercruiser inboard ignition wiring

If you look at the diagram you will see only 3 terminals being used. Question, does the switch in question have a push feature? If so it is an outboard switch which will not work. You can use an standard automotive switch, which may not last as many years due to materials it is made from. i.e. not brass.
 

1993 Mariah

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Re: mercruiser inboard ignition wiring

Reply to Captian,and anyone else with ideas!

i will check the ignition switch to see if it pushes in, if i need to change it out where will the orange wire go in a three prong setting.

this is how it is wired now.

red - on B (battery)
purple- on I (ignition)
yellow (no stripe)-on ACC
orange-on an elevated metal prong in the middle of the ignition (that elevated metal piece looks like a Y)

Hope its just the ignition could it be anything else making the boat want to keep starting and then die out? Like i said i just replaced the starter. and the feul pump is good, lines are clean too.
 

achris

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Re: mercruiser inboard ignition wiring

Reply to Captian,and anyone else with ideas!

i will check the ignition switch to see if it pushes in, if i need to change it out where will the orange wire go in a three prong setting.

this is how it is wired now.

red - on B (battery)
purple- on I (ignition)
yellow (no stripe)-on ACC
orange-on an elevated metal prong in the middle of the ignition (that elevated metal piece looks like a Y)

Hope its just the ignition could it be anything else making the boat want to keep starting and then die out? Like i said i just replaced the starter. and the feul pump is good, lines are clean too.

Resistance wire between the key and the coil.... Does it run with the key in the 'START' position, but stop when you let go?

Chris...........
 

1993 Mariah

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Re: mercruiser inboard ignition wiring

No, it starts when you manally turn the key over to the start, but when you let go of the key it continues to try to start the boat by itself unless you turn the key to te off position.

On the igition what is the ACC prong for? Is it for accessories?

if so that is what the yellow wire is connected to.

There is not a prong labeled "S" only a "I and a B and a ACC" the 4th prong is elevated in the center on a Y shape peice of metal. and not labeded as anything. I think the orange wire should go on the ACC prong and the yellow wire should go on the 4th unlabeled prong what do u think?
 

Bt Doctur

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Re: mercruiser inboard ignition wiring

the only one i see with a prong in the center says "starter".
"battery", "ignition", "access" are on on the edge of the switch.
try red to battery, purple to ign., orange to access, yel w/ red stripe to center of switch(solenoid)
 

1993 Mariah

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Re: Mercruiser inboard ignition wiring

Re: Mercruiser inboard ignition wiring

ok ill try that

In addition, Any ideas why, it starts when you manally turn the key over to the start, but when you let go of the key it continues to try to start the boat by itself unless you turn the key to the off position?
 

Bt Doctur

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Re: mercruiser inboard ignition wiring

you have power going to the solenoid in the "on" position and not the "start" position.
 

Bt Doctur

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Re: mercruiser inboard ignition wiring

by wiring up the switch correctly. lets forget the orange wire for now.
is there +12V on the red wire? that is the system main feed.
purple is the ign feed
yelly w/ stripe is solenoid
switch works like this
"on" position connects power with ign. when turned to "start" the yellow is connected to activate the starter, when motor starts and you release the key to come back to "on" .
power is only connected red to purple.
 

1993 Mariah

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Re: mercruiser inboard ignition wiring

Well i finally got the wiring right. then the boat was continually hard to start acting like not getting enough fuel and squealing it started and ran for a minute or so and the squeal stopped. then acted like choked out and died, I checked fuel line again main line is squirting fine into fuel filter checked filter had a little sediment, I cleaned out, restarted, same issue ran for a min then choked and died, checked filter again, clear, but fuel still coming from fuel line when disconected, reconnected all. I tried again. Harder to start each time. It keeps acting like not getting enough fuel. So tried to give it a little more fuel and a little more time to start. Finally my fear came true again, the starter burned out, again. Yep second time. Anyone know what the problem could be??? :confused::mad::(
 
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