This past season, my motor developed an idle that was a bit lopier than normal. I don't have stock cam, and it always was a bit lopy at times, but not constant. The last time it did this, it was a timing issue; which had changed a few degrees for some reason. I decided it was time to change spark plugs, which i did with no change to the idle. I did a visual check of the cap/distributor clocking, and it hasn't changed. I haven't actually checked the timing yet, but will. If memory serves me correctly, it was set at 9 degrees in base timing mode; as it idled best there. I'd like to change the cap and rotor as it has been on there for approximately 400 hours. Wires as well. The current cap that is on there is gold. I'm noticing that the stock mercruiser cap is black. I havn't pulled the cap to see if there is a manufacturer stamp in it, but does anyone know what it may be? Should I go with aftermarket or stock merc? My engine is slightly modified, putting out approximately 465hp.

Gold ?? Ive seen tan, just put on the stock black cap, it will cross to an AC Delco part #

I found this thread when doing a google search. Funny enough, this is the prior owner of my boat inquiring about the same thing. Not a lot of suggestions however...

Distributor Cap/Rotor & Plug Wires502 Mag EFI!

It may be tan..... I haven't looked at it since October..

You should have a EST (808483T3) distributor but could use the serial number to verify
Suggest a Merc cap and rotor

https://www.mercruiserparts.com/bam/.../31912/4854/70

i'm thinking this is what is in there..........

https://www.holley.com/products/igni...ors/parts/8132

Base timing is 8 BTDC, and depending on which MEFI you may need to manual increase the rpm

When you said gold I was thinking maybe tan which is Accel, as you found out. I’m sure this will open the can, but, I went with a MSD cap. Nice heavy thick cap and rotor, and DUI wires. There heavy wires with sleeves. Not listed as marine apps but if you get the ones for big block Chevrolet, “under header” they work. I think BUP on here has a source for some marine specific applications on wires.

Ok, thanks.

I got caps, rotors, new ignition coils and pick up coils from BUP for my 502 MPI's. No China eBay crap either. He also has Marine specific Moroso ULTRA 40 wires that are sweet for this app. Highly recommend him for all of this.