Timing Mercruiser 305 5L

[Anthony200482]

I am trying to set the timing on my 1991 mercruiser 305 5L but I do not have the wiring diagram. I know that on GM SBC you have to disconnect the tan wire to bring it to zero, but there is no tan wire coming out of the ICM. <br /><br />Does anyone know which wire to disconnect when setting the timing or does anyone have a wiring diagram for the ICM and Distributor? Any help would be great. Thanks

 

[JB]

Re: Timing Mercruiser 305 5L

Mercruiser is not an outboard, Anthony.<br /><br />I will move this to the Mercruiser forum.

 

[rbezdon]

Re: Timing Mercruiser 305 5L

you likely have points in the engine so no tan wire. Just set the timing for 8 Deg BTDC at 650 RPM and your good to go

 

[Don S]

Re: Timing Mercruiser 305 5L

I know that on GM SBC you have to disconnect the tan wire to bring it to zero, but there is no tan wire coming out of the ICM.

I'm a certified (some say certifiable) Merc marine tech and have never heard of that before. Mind explaining where you heard this from, and some more details.<br />Being a 91, you should have a Thunderbolt IV igniton system, and just aim the timing light and move the distributor to the proper degree/@ rpm from the manual.

 

[Anthony200482]

Re: Timing Mercruiser 305 5L

Thanks guys my mistake.... I am thinking GM on vehicles, as I know now that marine is different. I will set it at idle.