# Mercruiser Ignition Timing



## diesel84 (Oct 25, 2007)

I am not very familiar with the timing procedure on my inboard it is kicking my ass...I have replaced plugs, wires, cap, rotor, and ignition position sensor. I might have additional problems. At this point I am ready to take it to a shop....ANY recommendations??? It is a 98 Mercruiser 350 MAG multi-port injection with a digital ignition system.. I would be glad to pay someone to come diagnose or time it for me.


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## The Maintenance Shoppe (Nov 5, 2007)

Why the parts replacement? What was the original problem???


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## diesel84 (Oct 25, 2007)

Original problem was little or no spark and motor would turn over and over then eventually fire after 10-15 mins and run fine. Then it got to were it wouldn't run at all. Boat needed a tune up so performed one I noticed cracked ignition sensor in distributor and replaced. Now motor will crank but is way out of timing back firing and missing. I tried grounding out the purple/white wire going to the ignition sensor and set base timing with no luck .


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## Kim (Aug 5, 2008)

You in Fort Walton by any chance? I have the Mercruiser diagnostic programs on laptop and a hand held scanner. The plug on the right hand side in that top pic is saying plug me in!


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## SHO-NUFF (May 30, 2011)

Did you actually remove the distributor from the engine to replace the ignition sensor? Were any of the plug wires removed, and if so put back in the right place on the distributor cap? Check the firing order for crossed plug wires.


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## diesel84 (Oct 25, 2007)

I am in Pensacola I wish I had a scanner that would hook to it I dont believe my Snap-on Solous will hook to it... I have never removed or repositioned the distributor it is still at the same position it was in when the motor was running perfectly. I am pointing towards the external Ignition control module but I dont want to just throw parts at it...


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## TheCaptKen (Mar 14, 2011)

You will need the module to plug into the harness in order to lock the timing so it can be set. Then you set it like any other engine.


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## Kim (Aug 5, 2008)

How many beeps when you turn the key to the ignition position? If you didn't move the distributor then you didn't change the timing setting. You only ground the purple and white wires on the data plug for carburetor engines, for MPI engines you just have to jump A and C (purple and white) on the data link plug to put the ECM into base mode.


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## MGuns (Dec 31, 2007)

I would recommend Shane Livingston of Livingston Marine at 850-375-0435. He's extremely knowledgeable and very reasonably priced; one of the best I've found. Give him a call and talk to him; that doesn't cost anything.


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