firing order

[bra549]

the firing order for 1975 mercury 650 3 cylinder is 1-3-2??? backfires thru exhaust. has spark on 3 cylinders. maybe wires been crossed?

 

[The Force power]

the firing order for 1975 mercury 650 3 cylinder is 1-3-2??? backfires thru exhaust. has spark on 3 cylinders. maybe wires been crossed?

Welcome to IBoats
1-2-3 is the correct firing
Has the timing been set correctly?
What are your compression-readings?
Here's a link to check the the ignition-components;

https://www.cdielectronics.com/wp-content/uploads/2016/12/7th-Edition-Troubleshooting-Guide_RS.pdf

 

[bra549]

big thanks for info. when weather clears up, get on it. let you know how it goes.