496 HO, NO Crank, No start
 

Hello
Hoping for some help. Does anyone have the ignition/starting schimatic for a 2007 or new 496ho/8.1 mercruiser with starter relay, Not A Slave.
Just reinstalled both engines, Starbord engine fires, runs great. Port engine is a no crank. Have check power everywhere, ignition has power at all terminal in run position.
Starter relay has power, can jump relay to engage starter. Relay has 4 wires, red with purple stripe, Yellow with red, Black with yellow and Yellow with black stripe.
Yellow wire with black stripe has no power with key in run postion. Need schimatic to see where this wire goes. Have jumped neutral safety switch, not the issue.
Have checked all connections.
What am I missing?
All help much appreciated!
Dan

see if this helps

https://cimg0.ibsrv.net/gimg/www.off...4e0a1cc4f7.jpg

Thank you for this, I do have a 14 pin connector, not sure if that makes a difference. Also, what is a MIE transmission switch?

Looks like its a nuetral safety switch in this diagram, also I think that this is a schematic with a slave.
My wiring has nuetral safety switch with a yellow with red trace, also i jumped the nuetral switch, didnt help.
Thank you, I do appreciate the help.
dan

Im not for sure, I picked it off this thread

https://www.offshoreonly.com/forums/...ness-dash.html

I can find wiring diagrams for everything with a slave selonoid. Why is there no schematic for 2007 and above with a starter relay instead of a slave? Need to know where one wire goes from the relay, yellow with black tracer, on my 8.1 merc.
Very frustrating.
Hope someone has the the schematic to help me.
Dan

I have never seen a mercury engine that did not have a slave but who knows. they did it because they did not know what the engine was going in and did not want the starter wire from the dash to be 40 feet long so they have it run a slave to power the solenoid on the starter itself. the transmission switch shown in the diagram is the neutral switch. do you have transmissions or bravo? if bravo it would use a switch on the shifter and if trans then the one on the trans as shown. not both.

I believe from2007 and up, Mercruiser switched from a slave selonoid to an actual starter relay, that is what I have. No Slave.

all the starters have a solenoid on them the slave just activates it rather than the wire in the harness from the dash. do you have transmissions or bravos? some engines have what looks like a ford solenoid on them rather than a relay but they do the same thing which is supply the starter relay on the starter with a better power supply for the yellow/red wire.

I have bravos.

just to make sure, are these mechanical or dts and or smartcraft? on the diagram i found for a 14 pin mechanical it shows a slave relay I believe up next to the pcm with the other relays. also just to make sure, is it having a kill switch problem? if you have a single kill switch for both engines it is a double pole switch so one side could be dead.

smartcraft, my issue has started since i just reinstalled the engines, port motors runs great, starboard wont crank. I have to of missed a connection, but I cant find it.I have power at the ignition switch, alarm goes on, fuel pump runs, just wont crank. I have power at the relay on both yellow/red and red/purple wires. I have swapped relays with port motor. I am at a loss. Need schematic to trace the other wire on the relay.

so I am assuming that the yellow/red only has power when the key is turned to start. the red/purple is constant power so that is there. there should be a second yellow/red that goes to the solenoid on the starter and there should be a ground wire. maybe missing the ground as in the diagram above with the transmission the ground is thru the neutral switch and is the yellow/black but on a bravo the ground should be permanent and the neutral is in the yellow/red.

My relay wiring is as follows: 30 pin is red/purple , 85- yellow/black, 86- black/yellow and 87- yellow/red. Here are some pics, I included a picture of my nuetral safety switch wiring.
https://cimg9.ibsrv.net/gimg/www.off...2c77e0ed28.jpg
https://cimg1.ibsrv.net/gimg/www.off...2a55b22669.jpg
https://cimg8.ibsrv.net/gimg/www.off...1aba2fcfe0.jpg

red/purple should be constant power, yellow/red goes to the starter. if you remove the relay and jump those two the starter should spin. the other two activate so we need to know which is which. thinking the black/yellow is ground but hard to tell. take a test light and go to battery pos. and one of those should light as the ground. the other should light when the light is on ground and the key is start. hard to tell on the neutral switch, assuming the purple are the switch itself but what are the colors on the other side, look like maybe black/yellow and yellow/red?

Yes that is correct, neutral switch is yellow/red and black/yellow

You are correct, my problem is the yellow/black wire that should light when key is in start position does not, no power. I dont know what to check, any idea where that wire goes? Is it fused? Thank you for your help on this!
Dan

if i am following correct then the black/yellow should light at the relay when key is in start. if it does then the yellow/black should be a ground as it is on a trans version which would mean that it is not connected to ground. is this the correct harness? I had a 496 here a while back that was originally a trans engine but was now wired for bravo and they had to find the original wires for the trans neutral switch and tie them together

Im using my sons login, Acually, the yellow/black should light when key is in start position. I verified this on my port motor. I followed the yellow/black wire to the 14 pin connector, it turns into a yellow/red wire on the helm side of the wiring. Im going to check power at the neutral safety switch on my shifter to see if there power from the ignition switch in start position. Do you know if this is fused or not? This is what Im thinking anyway. If you have any other ideas, please let me know, I do appreciate your input.
Dan

never seen a fuse on any start circuit before. if the yellow/black at the relay is hot for start and if you have that at the relay make sure the black/yellow is a ground. if the yellow/black is not hot when the key is in start then you are losing it at the neutral or a wire broke somewhere.

Ok great! That is what I'm thinking. I will double check the ground just to be sure, since I can jump the relay to make the starter spin doesnt that mean my ground is good?

if you are jumping the red/purple to the yellow/red at the relay then no that has nothing to do with the ground. those are the two that make a connection when the relay pulls in.

Oh ok, that makes sense then I just need to hook my test light to pos on battery and touch the pin for the black/yellow wire, if it lights, I have good ground, right.

correct

[QUOTE=compedgemarine;4873583]never seen a fuse on any start circuit before. if the yellow/black at the relay is hot for start and if you have that at the relay make sure the black/yellow is a ground. if the yellow/black is not hot when the key is in start then you are losing it at the neutral or a wire broke somewhere.[/QUOTE
PROBLEM SOLVED!!! Traced everything down, jumped the neutral safety switch on the shifter, we have power, starter spins. My only question left is how does a switch go bad sitting on a trailer in storage for the winter? Amazing!
Last question, if the neutral safety switch is on the shifter, what is the switch for on the shifter cable on my transom for?
Thank you for help this, it is greatly appreciated!!
Dan

may be for the smartcraft so the pcm knows it is in gear but that is a guess. glad you got it figured out. things die especially when sitting.