Timing for a 502 Mag MPI
 

I have twin 502 Mag MPI's and it is time for servicing. I am running Stainless Marine exhaust and Vortex air intakes, everything else is stock. I will be putting in Rapid Fire #1's. What do you guys recomend for the base timing???? Should I stay the Mercruiser's recomendations?? Please advise.

Thanks
Dail

Re: Timing for a 502 Mag MPI
 

I wouldn't drift too far from Mercruiser's recommendations if the motors are mostly stock. See how it runs with the factory settings then advance in small increments like 2-4 degrees if you feel there is room for improvement. I had my timing advanced by almost 4 degrees with a cam and exhaust then i got a bad tank of fuel....I couldn't run over 3800-4000 rpm until the bad gas worked its way out. I just backed off 2 degrees today. I feel a little safer now, its hard to hear detonation until its too late.

Re: Timing for a 502 Mag MPI
 

How are you changing the timing? Do you have a way to set the computer in timing mode? Thnks Dwight

Re: Timing for a 502 Mag MPI
 

Dwight,

We will be using a Mercruiser Scan Tool and will be placing the ECU into Base Timing, then making any adjustments if needed.

Thanks
Dail