Mercruiser 140 Valve Order

[myoldboat3]

GM Engine 140 HP 4-cyl 181 cu.in. s/n 3888148
Mercruiser "Late Model I" Stern Drive s/n 3901959
1974 Harris Flote Bote, 28' pontoon

Note: The head gasket was blown between cyl 2 & 3. I will update my "Merc 140: Sudden RPM Drop, Rough Idle, Engine Shake" thread once I complete the repair.

I'm getting ready to adjust the valves. The manual for my engine s/n (Mercruiser Service Manual Number 2) on page 5A-3 lays out the valve order:



So it's E II EE II E, which matches my photo of my head (yes, *before* I cleaned it up):



As I understand it, the intake valves are the larger diameter (presumably to allow plenty of combustion air?). This is from the manual for later-model Mercruiser 3.0L engines (Mercruiser Service Manual Number 13), page 3A-20:



Oddly, I cannot find the valve order listed in this 3.0 manual, but I did find that image showing the larger intake valve head. Not that it matters, because I am going by the correct manual for my engine s/n.

Anyway, I would just like to have someone more knowledgeable about all this confirm that I have the valve order correct. The reason I am questioning it at all is that I have seen online discussions saying the order is I EE II EE I, and saying that is an "industry standard". Did Mercruiser ever change the order? Do other inline 4's use that flipped order?

Thanks in advance.

Steve

 

[Bt Doctur]

the order is correct shown in the picture E,I, I, E, E .I, I, E
Some Ford heads are E I E I E I E I
To adjust, the best way I have used is rotate the engine until the intake valve opens and closes, this cylinder is now on compression stroke. Adjust push rods to just able to spin with fingers and then a 1/2 turn more.

 

[myoldboat3]

Thanks, Bt Doctur1.