‘94 454XL MSTS timing

Recently, due to a bad riser, I had to replace a valve in my starboard motor. Got her all back together, set the distributor good enough to get her started and all is well. Now I need to time it and can find any info on how to do the initial timing. I’ve read a lot of forums talking about a plug that reads run and time on it and you have to turn the plug to do the timing. These motors don’t have them. They are 1994 454XL carbed motors with the MSTS ignition. Somewhere else I seen where you jump a plug with purple/white wires in it. I found such plug but when I jumped it the engine breaker popped, obviously not it. I’m supposed to be making a 90 mile run with the boat tomorrow and don’t want to burn anything up. A buddy told me to just put the light on the port motor and see where it’s at then set the starboard motor the same way but I know that’s not the correct way. Any help would be greatly appreciated.

An initial timing connector must be unplugged to set the ECM to zero advance. (pink wire with black connector) Run engine at 1200 rpm, with timing light, rotate distributor to 10 degrees BTDC. Don't forget to plug the timing connector back in.

kevin_z said:

An initial timing connector must be unplugged to set the ECM to zero advance. (pink wire with black connector) Run engine at 1200 rpm, with timing light, rotate distributor to 10 degrees BTDC. Don't forget to plug the timing connector back in.

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Thats the problem. I can’t find any such connector.

What you read regarding the plug that you flip over applies to an EST distributor when it runs in stand-alone (no ECU) mode.....the MSTS system uses the same EST distributor but has an ECU to vary the timing based on the MAP sensor and the knock sensor outputs. To 'freeze' the advance, the MSTS module uses its unique method that Kevin_Z described. Look for a short loop pulled out of the main harness, on top of the intake manifold, with the connector in the loop.

Thanks for the responses. I’ll be down there this afternoon and have a good look around. I’ve also read that these motors have info decals with timing specs. Once again, not that I’ve seen. Most of what I be seen calls for 10* btdc at idle. Sound right to you guys?

Maybe this will help....its from the parts manual and shows the connector and wire loop, coming out of the MSTS harness...

makomark said:

Maybe this will help....its from the parts manual and shows the connector and wire loop, coming out of the MSTS harness...

Click to expand...

Indeed very helpful. Thanks.