Adjusting rockers? 3.0 mercruiser

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jedimaster

Petty Officer 1st Class
Joined
Jun 8, 2006
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336
Hey, I was wondering what the correct procedure is for adjusting or setting the rockers? To my understanding they are hydraullic lifters? Any feeler guage type adjusting required?
Its an 1988 3.0 140hp mercruiser
 

Haut Medoc

Supreme Mariner
Joined
Jun 29, 2004
Messages
10,645
Re: Adjusting rockers? 3.0 mercruiser


Valve Adjustment
Engine Not Running
With valve cover removed, adjust valves when lifter
is on low part of camshaft lobe, as follows:
1. Crank engine with starter or turn over in normal
direction of rotation until mark on torsional damper
lines up with center ?0? mark on timing tab, and
engine is in No. 1 firing position. This may be determined
by placing fingers on No. 1 valve as
mark. If valves move as mark comes up to timing
tab, engine is in No.4 firing position and should be
turned over one more time to reach No. 1 position.
No. 1 Cylinder - Exhaust and Intake
No. 2 Cylinder - Intake
No. 3 Cylinder - Exhaust
No. 4 Cylinder - Intake
2. With engine in No. 1 firing position as determined
above, the following valves may be adjusted:
3. Back out adjusting nut until lash is felt at push rod,
then turn in adjusting nut until all lash is removed.
This can be determined by moving push rod upand-
down while turning adjusting nut until all play
is removed.
4. Hydraulic lifters now can be adjusted by tightening
adjustment nut an additional 3/4-turn. Valve
lash should be checked after engine has run and
reached operating temperature.
5. Crank engine one revolution until pointer ?0? mark
and torsional damper mark are again in alignment.
This is No. 4 firing position. With engine in
this position, the following valves may be adjusted:
No. 2 Cylinder - Exhaust
No. 3 Cylinder - Intake
No. 4 Cylinder - Exhaust
6. Install distributor cap, spark plug wires and coil
lead.
7. Install rocker arm cover; torque to 40 lb. in. (4.5
N?m).
__________________
Here ya go!.......:)
 

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: Adjusting rockers? 3.0 mercruiser

Take notice that the adjusting nuts are a crimped top self-locking and can 'go soft' with repeated use, that is, the locking portion wears out making the nut relatively easy to turn onto the threaded stud.

PAY ATTENTION too the force used on each one, if ANY feel noticably easier to turn then replace atleast that one, preferably all.

Personally, I throw them all away and use poly-loks, many after-market brands handle what is essentially a long nut and an allen set screw, adjust the nut and hold it with a wrench, tighten the set screw (through the nut) jamming the set screw to the stud, 100% locked and reusable.

The only catch, they are packaged for V-8's, 16 at a time.
 
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