timing

[mrxitmt]

OK I did some research . I have the thonderbolt V (5) ignition so it says to ground the
purple/yellow wire (now I know what that wire hanging there is for) and set the distributer .As I said before there are no degree marks on the chain cover or the balancer , just a v notch on the cover and a line on the balancer . So I set the timing line at the notch and when I un grounded the wire the setting went back to before the notch BTC Maybe that's how it's done .Any comments?

[pascavone]

i might be mistaken, but i thought the octane sensor advanced and retarded the timing for the fuel used?

It's not like the old days of vacuum advance and 4 degrees before top dead center.

[mmwjr]

Rick see attach for instructions I found. BTY I don't see any purple/yellow on any of my wiring diagrams. Should be purple/white

[mrxitmt]

Thanks for the instructions. I will double check everything aagain before my next run ....OK so it's purple white then.

[mmwjr]

Pas I have been learning a fair amount while fielding questions on this site. Best I can tell it wasn't until 1998 when mercruiser started using the newer small block V8s that required electic fuel pumps and had provisions for knock sensors and alike. There is also difference between carb and EFI set ups which merc still offers both today.

I believe the 4.3 V6 started changing over earlier as I had a 1992 with an electric fuel pump but not other modern sensors. Also haven't looked at the big blocks enough except that beyond the 7.4 the 8.1, 8.2, and so forth were all high tech.