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No spark Mercruiser 4.3 mpi

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sdwazup

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Motor ran great until I had a loose hose on the raw water pump. To get to it the exhaust manifold and fuel filter had to come off. Got it back togetherand no spark. Replaced the coil, cap and rotor. No luck ! Had a marine mechanic come out with the computer and I had a bad relay. Put a new on in and hooked to computer again. The reading said "coil has an open circut". The mechanic is MIA so I'm wondering what to check next ?
 
sdwazup said:
Motor ran great until I had a loose hose on the raw water pump. To get to it the exhaust manifold and fuel filter had to come off. Got it back togetherand no spark. Replaced the coil, cap and rotor. No luck ! Had a marine mechanic come out with the computer and I had a bad relay. Put a new on in and hooked to computer again. The reading said "coil has an open circut". The mechanic is MIA so I'm wondering what to check next ?
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The relay wouldn't go bad just because the exhaust manifold and fuel filter were removed. If you have a multimeter and a good battery, you can check relays. If anyone works on your boat or other vehicles, always get the old parts.

Start by acquiring a service manual if you want to do some of the troubleshooting. Ebay has them- you don't need to pay full price.

I would recommend taking it to a service shop that's trained for Mercruiser, so they have all of their tools and diagnostic devices/technical info available.

Does it have spark? Did you check for fuel delivery? If it has spark, squirt some gas into the throttle body and see if it wants to run- if it does, find out why the fuel has stopped. The service manual has diagrams, specs and info for troubleshooting.
 
The serial number is 1A054765.
I've got the service manual or at least the one your talking about. Mercury service manual #32.
It's got power to the coil and the fuel rail is pressurized and seems to be fine.
the mobile mechanic had the Mercury computer program and the code it gave him was that the coil had an open circut
 
sdwazup said:
had a loose hose on the raw water pump…no spark…
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Being the engine appears to be a Fresh Water Cooling system and work and/or water was in the area of the Crankshaft sensor, you might want to thoroughly inspect the sensor and wiring going to the sensor for damage such as rubbing through the wires, etc…. Item number 9, https://www.marineengine.com/parts/mercury_marine_parts/sn/1A054765/42410HMUS/13808_110

1A054765 = MERCRUISER 4.3L MPI ALPHA 1.7R FWC DRAIN 4.3L ALPHA MPI Model number 42410HMUS.

Also double check the mercruiser shift interrupter switch mounted to the exhaust system since work was done there as well. Item number 18, https://www.marineengine.com/parts/mercury_marine_parts/sn/1A054765/42410HMUS/13808_290
 
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sdwazup said:
The serial number is 1A054765.
I've got the service manual or at least the one your talking about. Mercury service manual #32.
It's got power to the coil and the fuel rail is pressurized and seems to be fine.
the mobile mechanic had the Mercury computer program and the code it gave him was that the coil had an open circut
Click to expand...
if you take the hi volts wire off the dist cap and hold close to a ground to you get spark off the coil?
 
Well Mr Fun Time's, you hit the nail right on the head !!! The connector going into the crank shaft sensor indeed did have a broken wire ! I want to thank all the contributers to this forum. You guys are very helpful, you save people a lot of money and most of all you know your **** !!! Being someone who busts my ass 7 days a week and still doesnt have a lot of extra cash, you all are very much appreciated !!!!
 
Glad you were able to find the issue plus overcome the situation... Thats sometimes a tight area to work in and wouldn't be the first for this same thing happening... happy boating and thanks for the nice words to us all that try our bests on here where we can. :)
 
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