Firing Order - Ford 302 - 888 Merc

[kwoolard]

After looking through my shop manual last night at the firing order on my 1974 Ford 302 Merc - 888 model I was a little confused. My manual states that the firing order should be 13726548, yet my manifold has casting numbers for the firing order 15426378. I assume that last one is correct since the engine ran fine before, but just wanted to question the order mentioned in my book. Are there different firing orders for the Ford 302 around the Ford/Mercruiser years?

 

[Fishermark]

Re: Firing Order - Ford 302 - 888 Merc

Ford did have two different firing orders based on what cam was used. If the engine ran fine with the latter, then that's what I would stay with!

 

[Fishermark]

Re: Firing Order - Ford 302 - 888 Merc

Here is some additional info I found on another site:<br />"Many Ford marine 302 engines are equipped with Ford 351 camshafts. This will require the use of the 351 firing order. It is 1-3-7-2-6-5-4-8. If you install the spark plug wires in a 302 order and the engine starts and idles OK, but backfires through the carburetor when the throttle is advanced, change to a 351 order. The other way to find out which cam you have is to remove the valve covers and observe the valve sequence as you turn the engine by hand or bump the starter with the coil wire disconnected "<br /><br />Hope that helps. (Illustrates why I am a Chevy man! )

 

[kwoolard]

Re: Firing Order - Ford 302 - 888 Merc

Thanks for the info to help clarify that subject! I'm a Chevy man myself, however I have no choice in the matter for the marine side of things with a Ford engine already equipped. Too costly to convert!

 

[JasonB]

Re: Firing Order - Ford 302 - 888 Merc

Be careful at the #1 on a Ford is opposite side to a Chevy. It's the piston opposite the fuel pump. Caused me much grief until I rememberd that tidbit. <br /><br />I think *most* of the mercruisers used the 351 order, but don't hold me to it. The order was often stamped on the intake manifold I believe.

 

[Boomyal]

Re: Firing Order - Ford 302 - 888 Merc

Can't speak with certainty for Mercs, but my 190 hp OMC 302 has 351w heads, a 351w camshaft and a 351w firing order. Being that it has a 302w intake manifold, the factory actually ground off the 302w firing order.<br /><br />I believe the Merc 302 @ 188 hp is the identical engine. In the mid 70's OMC used two versions of the 302W. The 175HP was a straight through 302w. The 190 hp was configured as described above.