timing a 3.0 Merc

[70mustang]

I have a 1990 Maxum with a 3.0 merc I/O. The timing specs say 2 degrees ATC. My timing scale is a black metal plate with about 4 teeth on it. I can't tell where TDC is not to mention which way is 2 degrees ATDC. I know how to use a timing light on an old mustang. Is there anything differnet with the boat motor? Please help with a quick timing lesson with a timing light and how to find 2 degrees ATDC. Thanks in advance.

 

[Don S]

Re: timing a 3.0 Merc

Here is a post with what is needed to set the timing on a 3.0L with the EST distributor, which is the only one that should be set at 2° ATDC.<br /><br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=24;t=011989 <br /><br />As far as your timing marks go.<br /><br />

 

[70mustang]

Re: timing a 3.0 Merc

Thanks Don,<br />I was told by someone that I may need to ground the distributor to make sure the distributor advance is zero. Does this sound familiar.

 

[Don S]

Re: timing a 3.0 Merc

You don't ground it, did you look at newport daves diagram in the link I gave? It should have answered your question. That image is from a Mercruiser service manual and is EXACTLY how to do the job properly.<br />Here, I copied his picture here for you. Hope dave don't mind.<br /><br /><br />