delco est timing specs

[chknfrmr]

Good morning folks. I have a 2003 4.3 mercruiser. The engine diesels when shut down after running at higher rpms. I would like to check the timing, but not sure what the proper timing specs are. The previous owner replaced the thunderbolt 5 ignition with a delco est ignition system. According to the flame arrestor, base timing is 8 degrees, but some of what I read online says to set base timing for a delco system at 1 degree. Which is correct?

 

[Scott Danforth]

you set the EST to 1 degree with the shunt connected.

regarding the EST, you should be all-in at 24 degrees about 2800 RPM

however check your fuel filter content, and the fuel pressure.

 

[chknfrmr]

you set the EST to 1 degree with the shunt connected.

regarding the EST, you should be all-in at 24 degrees about 2800 RPM

however check your fuel filter content, and the fuel pressure.

Thanks Scott. The fuel filter content is fine, checked that previously due to a running rough issue with suspected bad gas. Ran the carburator through my ultrasonic cleaner and the running rough cleared up. The dieseling was pre existing and is still present. I will check fuel pressure

 

[Scott06]

Thanks Scott. The fuel filter content is fine, checked that previously due to a running rough issue with suspected bad gas. Ran the carburator through my ultrasonic cleaner and the running rough cleared up. The dieseling was pre existing and is still present. I will check fuel pressure

Without the shunt in at idle will be about 12-15 degrees . Scott has you steered straight with the 24 ish total degrees.

When I had dieseling on my 3.0 fattening up the idle mix and decarbonizing the cylinder helped. Ran seafoam down carb while at fast idle til it stalled let it sit 30 min then bunch of black smoke. Also check the operating temp is ok will be worse if it runs hot.