Timing marks

[IanFS]

Mercruiser 4.3L V6 1988

My timing marks seem to have corroded away. She is running ok now I have rebuilt the carb and replaced the old fuel but I would like to check the timing. Here are two pictures one is what I think may the timing mark which I think is 8degrees before tdc, the other is the flywheel mark. Do you think I am correct with the arrows marking the bits I think are the right marks or am I way off base?


I'm pretty certain the mark on the flywheel is the marker for that so I'll put some white paint in it with a small brush but the others on the timing cover are puzzling me.

 

[Fishermark]

Re: Timing marks

This should help:

 

[Eric 3.7LX Alpha 1]

Re: Timing marks

You are correct on the balancer.

There are/were several marks on that tab. There is a pic of it in the service manual.

If you use an advance timing light, you only need the 0? mark.

 

[IanFS]

Re: Timing marks

There are/were several marks on that tab. There is a pic of it in the service manual..

Thanks Eric, but which one on my corroded tab is the one to time with?

Fishemark, do you think then that the O is where the indentation on my picture is?

 

[Don S]

Re: Timing marks

The groove in the vibration dampner is 0? TDC

 

[Fishermark]

Re: Timing marks

Fishemark, do you think then that the O is where the indentation on my picture is?

Yes - when the groove in the balancer lines up with the big indentation, you are at TDC.

 

[IanFS]

Re: Timing marks

Thats great, thanks for all your help everyone.

 

[IanFS]

Re: Timing marks

My timing light is only that...a timing light. It connects to the battery and then to No1 spark plug lead. I'm guessing the second mark in is the one I will use?

 

[Eric 3.7LX Alpha 1]

Re: Timing marks

You know you can probably get a new timing tab that uses two bolts from the timing cover to hold it in place.

 

[IanFS]

Re: Timing marks

I've checked the pdf in the Mercruiser manual several times but cannot find a page ditectly related to timing. Therefore I'm going to degrease and paint a line on the marker and then tune the engine. Thanks guys,

 

[Fishermark]

Re: Timing marks

It certainly looks like the arrows you have drawn on your last picture are pretty close to accurate. I would do as you suggest and make a mark... or even glue on a dot... or grind out a notch... something to mark where 8 degrees BTDC is and be done with it.

 

[IanFS]

Re: Timing marks

Dons picture didn't show in my browser the first time for some reason, but now it has and it makes perfect sense, thanks very much Don. And thanks to all you guys for your replies and help.

If the weather holds tomorrow (it's rainy and windy over here and it's Summer :facepalm I'll clean it up and put some marks on it.

Thanks again all of you.

 

[Hook1884]

1987 4.3l is it supposed to be 8btdc? Because right now I have it at tdc on pulley an timing mark on timing cover. As for my distributor it is pointing to the number 6.