Just running this past as a concept. Friends boat with 350SBC and a Volvo 280. 18ft runabout K&C hull. Does about 4.5mpg...well dialed in carbed with mech adv distributor.

Spends 8+ hours fishing offshore on the west coast. Idling or light trolling the entinre time.

I'm thinking that a vacu advance system would be a benefit to the idle and low rpm trolling scenarios. His base timing is 6° Adv.

I'm curious what the marine engine EFI ign timing tables are for idling and light rpm thrust for no wake zones etc.

stock 502 mag base timing.

On my example though you also have a spark stabilizer limit of 15.1 degrees so if its off target rpm, it will add, subtract up to 15.1 degrees to keep it on target. Then you have idle droop and idle flare stabilizer multipliers/ scalars that control how much/ how fast that timing is added, subtracted to keep it from hunting or flaring, Smitty

for all the fishing boats that idle 12 hrs a day we use the delco est system dist it idles 18-20 yet tops out at 30 on older 12 bolt non vortec engines or 26 for vortecs they work awesome for rev rotation you need to put a bearing in because the shaft pulls down msd makes one with a bearing

Good info. What idle rpm are you running?

Thank you Smitty. Always appreciate the good info.

I apologize for the formatting but for additional reference this is from a Marine Power 454 MEFI 1 table and a 1995 Merc 350 Mag EFI MP Mefi 1 table.Like Artic says these also employ a spark stablizer which has the actual true timing dancing all over at idle.


Marine Power 454 MEFI 1
Main Spark Advance vs RPM / KPA

RPM MAP

40 60 80 90 100

3600 40.1 40.1 35.5 32.0 30.9

3200 40.1 40.1 35.9 34.1 32.0

2800 40.1 40.1 36.9 34.1 33.0

2400 35.9 37.6 36.9 34.1 32.0

2000 33.4 35.9 33.4 32.0 29.9

1600 27.8 29.2 29.2 29.2 26.0

1200 26.0 26.0 26.0 26.0 21.8

1000 21.8 21.8 21.8 21.8 20.0

800 15.1 15.1 15.1 20.0 20.0

600 15.1 15.1 15.1 20.0 20.0
350 Mag EFI MP Main Spark Advance vs RPM / KPA

RPM MAP

40 60 80 90 100

3600 40.1 38.7 34.8 33.0 27.8

3200 40.1 38.7 38.0 34.1 28.8

2800 40.1 38.7 38.0 32.3 27.8

2400 40.1 38.7 38.0 32.0 27.8

2000 40.1 38.7 36.2 29.2 27.8

1600 15.1 38.7 32.7 25.3 24.6

1200 15.1 32.7 28.8 26.4 24.3

1000 15.1 26.0 24.3 24.6 23.2

800 15.1 25.0 22.1 20.0 20.0

600 10.2 10.2 19.3 17.6 17.9

most fish boats idle at 600 or above going lower is possable but we find keeping things circulating a bit is better

I wish there was a way to screenshotbmefiburn, is that from.a mefj 1 5.7 or mefi 3, smitty

Both are MEFI 1. My MEFI Burn is on a dual boot MacBook Pro and getting a screen shot from the Win XP Pro side over to a system I can post the picture is too much work. I'm lazy,,lol. Those tables I posted are from the actual download of the .bin file to text.

Oh and ti add one more piece of info theMarine Power 4454 was in a jet boat, The 350 Mag EFI MP was a 1995 era attached to a Bravo 1