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Merc no spark

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westy_two

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"i have a 1993/1994 5.0lx merc

"i have a 1993/1994 5.0lx merc it over heated due to impeller gone in the leg. replaced impellor since then i have had no spark. i have replaced the sensor in the dis, the rotor,cap,new ht leads and replaced the ign mod. im getting 12v on the coil. tested the coil works fine. if you tack the white/green wire bullet conector in between the ign modual and the sensor to ground, the plug sparks. but the white/green & white/red from the ign sensor does not spark.pcv switch has been disabled and the one on the stick works fine. tryed removing the taco gray wire still didnt work!!!!!!!!!! spent many days trying to fix this any ideas???"
 
"This may sound elementary, bu

"This may sound elementary, but is your throttle quadrant kill switch in the RUN position? I spent nearly 2 days trying to get mine running once, after a youngster with overly busy fingers flipped the kill switch to OFF without my knowing. Talk about PO'd!! Someone else's kid at that.

Make sure the shift interrupt switch at the shift bracket is centered in the V notch in the shift arm. If it's not centered there will be no spark. This only applies if its an Alpha or pre-Alpha drive.

Your tach may be shot. It completes the circuit from the neg side of the coil to ground, and if its open there is no spark. Do you have access to another tach you can try out?

Can't think of any logical reason why an overheating event should cause spark failure. I doubt the two are related, but it is a boat after all. If anything can go wrong, it will.
It's not EFI, right?
Rod"
 
100% sure its not any kill swi

100% sure its not any kill switch tryd puting it in gear and get nothing engine wont even turn. gd shout though. disabled the shift interuped sw as i thought might have been that. still the same but i do have a alpha drive. no access to another tach could i try grounding to neg on batt??

not EFI as far as i know.
 
"If you have a VOM try measuri

"If you have a VOM try measuring the resistance from the gray wire connection on the coil to ground. You should disconnect the wire first. If it's open circuit, either your wiring to the tach is broken, or the tach is open circuit. You can measure right across the tach connections next to determine which it is.
You may have corrosion in your 10 pin plug where the boat harness connects to the engine. The gray tach wire passes thru this plug. Should be at the aft, top stbd side of the engine. If corroded, clean the pins and receptacles out well with a Q tip and acetone or laquer thinner. You may need to use wet/dry cloth for heavy deposits.
Rod"
 
checked engine out was really

checked engine out was really simple in the end. the earth from the ing module to the dist wasnt that good so put in a link wire to earth works great!!!
 
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