Need procedure to time a msd ignition 502 stock cam
 

Boat is running real rough just replaced rotor and cap need to time. Due I need to stop the advance to get it right?

Re: Need procedure to time a msd ignition 502 stock cam
 

I believe at idle there should be an 8* advance and a full advance of 24-26* advance at 3200?????? Is there a way to stop the advance prior to timing?
Any help would be great really want it set up right for long run tomorrow.

Re: Need procedure to time a msd ignition 502 stock cam
 

You want 34 - 36* full advance. The base timing is not real critical. However, the more base, the better the idle. The downside to adding base is a harder to start motor, especially when hot. If you have an MSD distributor, the advance curve is fully adjustable. You set the amount of advance and also when it reaches full advance by different springs and stop bushings.

Re: Need procedure to time a msd ignition 502 stock cam
 

Changing the cap and rotor should not change your timing. If it was ok before you changed them, you should not need to reset it.

That said, timing is 8 degrees BTDC, and it must be set in "Base Timing Mode" (assuming you have 502Mag MPI). If your next question is "how do I put it in Base Timing Mode?", that's easy.

Hopefully you know where the DLC (Data Link Connector) is. Take off the cap. Look at the connector closely and you will see letters on the side marking each terminal. Find terminal "A" and "B". Then with the engine running at about 1400RPM stick a paperclip (or something) into them, connecting them together. The engine should drop to around 700 RPM. You are now in Base Timing Mode. Set the timing. When your done, pull out the paperclip.

I like to disconnect the MSD box and reconnect the stock ignition (only takes a few seconds) to time the engine, but you don't have to.

Dave

Re: Need procedure to time a msd ignition 502 stock cam
 

No I don't think it was right to begin with backfiring and the sorts :(
Sorry not an MPI. NA.

Checkmate454
Thanks I haved been searching this section and notice you have some good info on here I thank you.