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5.0 Mercrusier - will turn over but won't start

Bikini Mechanic

New member
2007 Sea Ray - had it out on the water and quit - had to be towed. Motor has lost spark. Motor will turn over, but won't start.
I am leaning toward replacing the Ignition Control Module. I think we were hit by lightening because our Jet Ski had the same problem and replacing the CDI fixed it. Any suggestions before I spend $600 on something I don't need. Thanks for looking.
 
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Any suggestions before I spend $600 on something I don't need.

Ayuh,.... Diagnose it, insteada throwin' money at it, Hopin' to get it right,....

There's a diagnostic tree in the Merc manual to pin-point the component that failed,....

Is there Power, at the coil's (+) terminal, with the key in the "On" position,..??
 
scroll down a few threads and read my thread... as it turns out the ignition sensor was bad on mine. 85.00 alot better than 600
 
Is this EFI or carbed motor??????????


You need a 12 volt test light to be able to do quick tests, Go to your local auto parts store and get a test light...........they are only about $10.00

a good digital multi meter (if EFI that has 10 meg ohm resistance built into it). (about $100)


Second. go to key switch. look at the back of it under dash.

there should be three wires........

RED...........battery 12 vdc

Purple.........Ignition ON

Yellow with red stripe..........Crank


There is a slave solenoid between the key switch and the starter solenoid. Typically on the left side of motor when looking at it and on the top.

it has red, yellow with red, on two large terminals and black and yellow with red on the two small terminals. The small yellow with red comes from the key switch. the large yellow with red goes to the starter. This is your cranking circuit..........

For a carbed motor (NOT EFI)

When you turn the key switch to the crank position to crank the motor over the ignition power is transferred thru the internal contacts of the key switch.


so when you are cranking the motor over 12 volts it transferred from the Bat + terminal to the yellow with red stripe terminal and also the purple terminal.

When you release the key to the RUN position the only connection is between Bat + and the purple wire.

This purple wire goes from the ignition key all the way back to the coil +. It is or has a couple of other connections such as the choke on the carb and possibly the fuel pump if electric.

So if you put the key to the run position you have to go back and see if there is 12 vdc at the coil +.

so without going any further answer the question............EFI or carbed.........
 
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