valve lash
Here's one for you Merc guys....
Got a carb'ed Merc MRE 7.4 bluewater in an '89 boat, but it has no identification on it - the only things I have found are some casting numbers, but nothing I can translate into exactly what Merc motor it might be. I'm pretty sure it's a replacement long block with the Merc 7.4 tin put back on it.
The heads are round port with screw in rocker studs - pic attached.
The reason I ask, my Merc manual says you don't set the valve lash, you just crank the rocker "bolts" down to 40 ft/lbs and your good to go. Now I know I'm not a Merc guy; heck, I'm not even a GM guy, but that just sounds too tight. Oddly, the book doesn't even say to set the lifter on the cam base circle....just crank 'em down to 40 lbs and go.
Further, I can find no refernce to screw in studs in any of my Merc literature. Again - I'm wondering exactly what this thing is. Looks like a Gen 4 7.4 (not to be confused with a 454, which is a different motor in Merc speak) but I'm sill not reconciling that with screw in studs.
On the back of the block, just behind the left head and the lifter valley are the following castings:
3935439
Conv2
GM hi-per
I suppose there should be a casting number behind the timing cover/water pump but I don't feel like tearing those off.
So....thoughts on valve lash? Could that 40 lbs actually be right?
Don
'01 22 Classic, 502/B1
And a bunch of other stuff
"If everything seems under control, you're just not going fast enough" - Mario Andretti