Mercruiser 120

[devans1]

Can anyone tell me the torque pattern and spec for a mercruiser 120 exhaust manifold and riser? Can't seem to find any info anywhere. R&R would be nice if you have any info. I used to be able to find all the OEM Service manuals online but they are no longer available.
Thanks in advance!

 

[Scott06]

Can anyone tell me the torque pattern and spec for a mercruiser 120 exhaust manifold and riser? Can't seem to find any info anywhere. R&R would be nice if you have any info. I used to be able to find all the OEM Service manuals online but they are no longer available.
Thanks in advance!

I dont have one but I suspect it is the same for the newer 3.0s if you can get that spec.

In absence of a spec I would tighten it from the inside out to the ends to 35 ft lbs and retorque after it gets hot. On my SBC I think the spec was 35 +/- 5 or so ft lbs. I believe they are grade 5 bolts to so don't too heavy on them, a calibrated elbow will work in a pinch

 

[nola mike]

For a 3.0, manifold is listed as 23 lb ft, and elbow is 20-25 lb ft.