tssteph

Anyone have any idea why my 350 mags (1998) don't have a timing tab? And better yet will a standard SBC timing tab for the correct size balancer work?

Iggy

EFI???
If so, then I believe the ECU electronically controls timing and the distributor is only set at an initial point.
If you don't have a distributor then the ECU controls the whole thing. A proximity sensor on the front of the engine or internally mounted reads off a segmented wheel and a crank position sensor tells the ECU where the crank is in rotation.

If you don't have EFI and the regular Merc Thunderbolt ignition, then you may have a problem. The timing tab is spot welded to the timing cover. You could add a bolt-on tab but you would have to find the exact top dead center of cylinder #1 to align it with the notch on the balancer. A degree wheel and a dial indicator long enough to reach down through the spark plug hole and contact the piston top is needed to do this.
In which case it would be easier to pull the balancer and replace the timing cover.

Badtoon

Wait!!!!
On mine with thunderbolt (nowMSD) the balancer has the degrees marked on it, under the Mercury paint, and a groove cut across the balancer at top dead center. There is a tab,not the normal SBC tab, on the front of the engine and it is painted black and not easy to find but it's there. That is for a carburated engine. Now I believe if I remember correctly from looking in my Merc service manual it's the same for the MPI engines. There is a special tool for MPI to lock the computer out to set base timing and a purple & white wire to ground out to set base on carburated engines. I hope this helps. I know I'm good on the carb set up but on the MPI I'm trying to remember what the BIG book said.

tssteph

It is a mpi engine. I will look again but I don't think there is a tab.

tssteph

There is nothing on port side area of the timing cover like a normal small block in a car. I have felt around by hand but don't fell anything anywhere else.

Badtoon

Ok
I looked it up in my Mercury book last night. It did not mention a timing mark but you need a Scan Tool or Timing tool connected to the DLC connector on the EFI/MPI wiring harness. This tool must give you a read out of the timing. On MEFI-1 models manually adjust the RPM to 1200 and on MEFI2 & MEFI3 models the ECM will adjust RPM to 1200. Timing is at 8* BTDC. This is out of my 1998 book. My boat is a 2003 but the engine is a 98??? I'm really l9liking my carb and MSD ingition. Hope this helps GOOD LUCK.

tssteph

Now I am really confused.. There does not appear to be a crank sensor near the balancer, without a crank sensor I am not sure how the computer can handle the initial timing. I double checked last night and there is no timing tab at all. I ordered one from Jegs for the balancer size I have and will check and see if it is 8 degrees off the balancer from the factory.

Badtoon

Acording to my book you set the initial timing with the scan tool or timing tool tapped into the computer. No need for a timing tab. I think it's time for you to order the Mercury Manual loik I did. No mention of conventional timing light for the MPI Engine only the Carburated Engine.

Plane Silly

Mine is a 99 MPI and it has a tab at about 1 o'clock (looking aft) cast into the timing cover with a "V" groove cut into it. TDC and 8* are marked on the balancer. I loosen the distributor, instal my scantool, hook up the timing light, set timing to 8*. It's just like old school, exceped insted of disconecting the vacume advance you plug in a scantool. Not sure about your timing tab? I would be glad to sent a picture of mine. Good luck.

Badtoon

The Scan Tool drops out the ECM so you can set the initial timing?