Mercruiser 470 Lost Spark

[kyddvicous13]

Hey everyone! We recently purchased our first boat from some friends, and were lucky enough that our first is a Grady! Its a 79 Chesapeake 212 with the 470 190hp engine. The boat had been sitting for a couple years, so I had the carb rebuilt, new plugs, changed oil, and changed coolant to start. I ran fresh fuel to her and it fired right up, and idled smooth. After about the third time I started I went to shift it into gear and it died. I am getting fuel but have lost spark. I have replaced the wires, coil, distributor cap, and even run a jumper wire from the bait straight to the coil to bypass anything from the key to the coil. The previous owner had installed a pertronix electronic ignition conversion in the boat which is the only thing I haven't replaced yet. I ordered a new one, but if that doesn't fix the no spark than I am out of ideas! I have voltage going to the distributor just no spark at the plugs... Any other ideas of what could be causing this?

 

[seasick]

Pull the distributor cap and crank the motor over. See if the rotor is rotating. If not, gear probably broke or sheared off.
It could be even worse than that but one thing at a time

 

[kyddvicous13]

Rotor is spinning. I really hope its the ignitor and not something more serious

 

[JeffN]

I am not sure on this one as I don't have a wiring diagram for the 470 but I'll put it out there. Is it possibe that even though you have run from the batt. to the coil that the switch on the shift linkage that briefly cuts power to the ignition circuit when you shift is still in the circuit after the coil? I would not think so as you have power at the distributer but that may be something to check. If it is still in the circuit it might be hung up. I'm thinking that the ignition module you are replacing may well be the issue. Hope so. I used to have a clymers or some such for my 470s but after I repowered I think I gave it away.

 

[moorehaven]

Ask the question on breezeworks.net .The guys on that forum know really know their stuff about the mercruiser 470 That pertronix unit needs a certain voltage to work properly usually wired off the choke feed wire . But ask on the other forum to be sure .Good Luck

 

[kyddvicous13]

Thanks moore I registered. The switch was not wired when this happened, and the neutral safety has been bypassed. Like I said it could just be the ignitor, I hope so anyway.

 

[JeffN]

Let us know what you find.