Firing order

[Ronvwalker]

I bought used boat with sterndrive Mercruiser 3.0 140hp. Not sure what year Maybe 1974 to 1984.
Wonder if 1974 to 1984 firing order is same or different?

 

[BruceK]

Same 1 3 4 2

 

[Ronvwalker]

Thank. i did 1342 but not worked at all. Umm checked spark plugs working.
one time I set firing order 2341. Did running but noise rough then stopped.
i known1342 right one but not run. Umm

 

[Seastoke]

1 Kawakers
2 Brucek
3 Farsco
4 Deleted User
5 Porto
Do I have to name them all, advice , buy an AK47.

 

[BruceK]

Thank. i did 1342 but not worked at all. Umm checked spark plugs working.
one time I set firing order 2341. Did running but noise rough then stopped.
i known1342 right one but not run. Umm

Well that's the firing order. Only thing I can think of is to check the dizzy cap and points are firing on 1 just before the 1st piston reaches TDC and is sparking (remove sparkplug and earth it. Use a plastic straw down the plug hole to guage when the cylinder is approaching TDC. It may help to see where the cam is too at this point) . Not sure if you can remove and incorrectly fit a distributer but worth checking so you can iron out electrics to the problem as well as the camshaft is correctly timed. After that is a fueling issue

 

[Assassin]

You're not 180 degrees out are you?

 

[gordmac]

A straight four is nearly always 1342, if not it will be 1243. Nothing else.