1994 mercruiser 5.0 LX carbureted ran fine, barely fired, now no start

[spannerman]

Use an ohm meter between coil + and coil - and ypu should get a reading and again between coil + and coil tower, can’t say exactly what the reading is as I don’t know which coil you have but an open circuit reading meabs a bad coil, if you have a reading then it points towards ignition module or Hall sensor in the base of the dustributor depending on the type you have. A quick check is take the coil - wire off and with power on the purple to the coil flash the coil - to earth and you will get a spark if the coil is good.

 

[Neverdie38]

I messed up earlier, i tested ohms with the wires on. New coil arrives today and i will change it after work. Thanks for everybody’s advice, it really helps because i’m not a mechanic. Cheers

 

[Neverdie38]

Installed a new coil and still no spark. Ran 12 V wire from battery to positive side of coil and it started. Bypassed the Killswitch and still do not have 12 V to the coil. It has to be the ignition switch then correct?

 

[Neverdie38]

At the ignition switch on the purple wire, I assume that is the purple wire that runs to the coil, I had power. I also had power at the tachometer. I did not have power after the tachometer. Does the 12 V power wire run from the ignition directly to coil or does it run to the tachometer and then to the coil?

 

[spannerman]

Purple is the ignition switch controlled 12 v supply to everything, it will feed into the engine harness for the coil and up to all instruments. If there is no power on the purple with ign on then its the switch thats failed.

 

[Neverdie38]

OK, that’s what I figured. Thank you. I have work today but tomorrow I will track down the purple wire. Something may have happened when I installed my radio. Boat is 30 years old so may be a simple pinched wire is the culprit. Thank you very much for everybody’s help!

 

[Neverdie38]

i finally figured out the issue. Some careless fool, me, cut the 12v wire going from instrument panel to coil while installing the radio. Careless mistake. Thanks again for all of the help. I really do appreciate it. Happy boating

 

[bowler]

Happy days. Easy fix in the end. Enjoy!