Is this the MSD # for a direct replacement coil in a '97 502 mpi merc ignition. I would like to try a hotter spark to clean up my transom a little.

I don't know about the part# but its the samre one that msd sells for the late 80,early 90 chevy trucks,Smitty
ps-don't ever crank your motor over with coil wire off

yes- that is the correct part #. I recently replaced my mercruiser coils with these.....but I have had some problems with them. Not sure that they are cut out for the abusive marine environment?? I had to replace one after just a couple of months. I now carry a spare on board but I'm thinking of going back to the mercruiser coils. Way too much $$$$$ but maybe they will hold up better???

I have tested the MSD coil vs the OEM coil and the OEM coil performs better on a stock ignition system. The OEM coil produced burn times (duration of the spark) of about 2.2ms, the MSD coil under the exact same conditions had burn times of about 1.7ms.

If your using a 6M-2 or other CDI box, the MSD coil may perform better, I don't know.

Dave

I want to try one, it sure seems it will provide a hotter spark than stock. Is it worth it or no?

Hi Float.. I think I have one of those new in box.. If you are interested I will ck the number and sell it to you for 1/2 of MSRP plus shipping.. I also have a nwe msd dist cap and rotor.

Chris
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you can't cure over rich mixture with the dreaded and mythical " hotter spark" . fix your injection ( probably low water temp because the tstat is wrong and its always at the bottom of the fuel curve) and that will solve your problem. incidentally.. you have much bigger problems than your dirty transom. if the boat is rich enough to do that, all that unburned fuel is wearing out your rings and diluting your oil such that the wear rates on every part of the motor increase by an order of magnitude.

solve the problem not the symptom