Mercruiser 3.0 base timing a myth?

[brian3127]

I bought an ignition module from a boat parts and repair place here in town.
I wired it exactly like the picture says and it doesn’t go into base mode. What do I do now. By the way it’s a freshly rebuilt engine so I want to get it right

 

[dubs283]

How do you know it isn't in base mode? Module will still advance timing in base mode, just won't push it up all the way

 

[aidanmurphy]

Is your black wire coming from the dist going to a 12V source? I would try and idle the motor and unplug / plug in the dongle. See if the RPMs change at all

 

[brian3127]

Is your black wire coming from the dist going to a 12V source? I would try and idle the motor and unplug / plug in the dongle. See if the RPMs change at all

I have the idle set to 650 rpms when doing both of these steps.

1. 12v at purple wire (tested 12v) plugged into black wire from dist., (white) jumper wires jumped. Idle does not change.
I have watched few videos on youtube and every time they plug these wires together the idle changes. my engine stays running the same. and timing does not change. so to me its not going into base mode.

2. Advance timing light
I plug all wires back to where they go. Set the timing light to 12 degrees. then set the timing to 0 and when I do that the idle goes up to about 800-850. lock the Dist. down
Then turn the idle back down to 650 and now the timing is at 2 atdc.

This is driving me nuts. any suggestions?

 

[alldodge]

I bought an ignition module from a boat parts and repair place here in town.

Was it genuine GM or after market?

 

[brian3127]

Was it genuine GM or after market?

I will have to look at it. I'm not sure. Figured they would have ordered a GM one.

 

[brian3127]

Was it genuine GM or after market?

would you have the part number for the genuine part

 

[alldodge]

GM 10482830

 

[alldodge]

Looks like newest number is 19418839

 

[brian3127]

Looks like newest number is 19418839

thanks i have my son looking for one he works at a GM dealership.

 

[brian3127]

Looks like newest number is 19418839

One more question.
Does the engine have to be running when switching the wires around. Or do you have to switch the wires before you start it.

 

[Scott06]

The instructions say to put the timing shunt in while it is running http://marineengines4less.com/images/companies/1/EST Ignition Instructions - ME4L.pdf?1431462059320

so i interpret this to mean start it with shunt disconnected from distributor then while engine is running connect it. Which way did you try it?

 

[alldodge]

Yes



Set timing
Disconnect white jumper and reconnect shift interrupter.

With timing light still connected, and engine at IDLE, verify that timing did advance to 12? BTDC, (plus or minus 2?). At 2400-2800 RPM maximum
(total) advance is obtained and should be 27? BTDC (plus or minus 2?).

 

[brian3127]

The instructions say to put the timing shunt in while it is running http://marineengines4less.com/images/companies/1/EST Ignition Instructions - ME4L.pdf?1431462059320

so i interpret this to mean start it with shunt disconnected from distributor then while engine is running connect it. Which way did you try it?

The shunt is connected at all times. Because you need the black wire connected to the interruptor switch for safety. But the white jumper wires are not connected

 

[Scott06]

The shunt is connected at all times. Because you need the black wire connected to the interruptor switch for safety. But the white jumper wires are not connected

Interruptor for safety? Shift interrupt is only to get it out of gear. Based on the instructions i would try it starting engine disconnected then connect while running

 

[brian3127]

Interruptor for safety? Shift interrupt is only to get it out of gear. Based on the instructions i would try it starting engine disconnected then connect while running

Ok maybe I used the wrong word (safely).
While running thats when we did it.

 

[brian3127]

Mercruiser 3.0 base timing is not a myth.
I bought a genuine GM ignition module and it goes into base mode now. Thanks for the help guys.