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Exhaust manifold

G

Ghg

Contributing Member
I have a 67 Mercruiser 120 153 cu in. Chevy 4 cylinder, the exhaust manifold has developed a rust hole on top of the rear exhaust port. Can this be welded or am I looking to replace it? I would preferably like to replace it. I’ve looked on eBay with no luck. The casting number is 35891 and it has a 64-72 parts range. Does anyone know of any salvage yards that specialize in used parts?
 

We have been thru this 1967 boat (with an assumed by me 1966 engine & drive) for months now. MerCruiser had a huge & rapid evolution in those years & serial number is the best way to find correct parts.

Regardless, I believe this is what you need. The last 3rd & 4th renditions are still available right here. (Same manifold, different t-stat housing). Open the link & compare images to what you have. You will need to click "previous" to see #'s rendition 1 thru 3.

Read & look closely at the images. Cast Iron, Aluminim, t-stat at rear, t-stat at front.....
I beieve you have the 3rd or 4th style. Difference is the t-stat housing & large hose at the front.
 
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Yes, I’ve been on this forum a number of times, we’ve had this boat since 1970 and been in storage for 13 years. Trying to get it in working order again. It’s been a rusty chain and trying to get all the links strong again. The casting number is 35891. It shows 63-66 110 engines and 64-72 120 Mercruisers
 
Yes but please for your own good please don't assume its a 1967 motor and reference it as such. You did so with the outdrive with separate oil chambers. All that did was get a bunch of DIY comments about buy SEI unit it will bolt right on..... which it WON'T.

I do believe your boat has the manifold, riser & t-stat an the image I directly linked to but could have the next earlier. Regardless, the difference is the t-stat & associated on the front. The manifold is the same. Look at those 2 images closely & you will see the difference at the front.

If you have the 35891 manifold with t-stat at rear then we are talking really early, look at the serial number range. Good luck finding that one.

The title of the parts link says 63-66 110 engines and 64-72 120 Mercruisers but you must decode it further. The link I posted is 1967 thru 72 (and I believe into the 80s if you search forward in model years). I also believe it is later 66 models. Look closely at what you have & compare images. Post a few pictures including front, side & rear & I can tell quickly.
 
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Ok, it’s actually a late 66 with separate oil chambers
Droid said:
Yes but please for your own good please don't assume its a 1967 motor and reference it as such. You did so with the outdrive with separate oil chambers. All that did was get a bunch of DIY comments about buy SEI unit it will bolt right on..... which it WON'T.

I do believe your boat has the manifold, riser & t-stat an the image I directly linked to but could have the next earlier. Regardless, the difference is the t-stat & associated on the front. The manifold is the same. Look at those 2 images closely & you will see the difference at the front.

If you have the 35891 manifold with t-stat at rear then we are talking really early, look at the serial number range. Good luck finding that one.

The title of the parts link says 63-66 110 engines and 64-72 120 Mercruisers but you must decode it further. The link I posted is 1967 thru 72 (and I believe into the 80s if you search forward in model years). I also believe it is later 66 models. Look closely at what you have & compare images. Post a few pictures including front, side & rear & I can tell quickly.
Click to expand...
I’m not near the boat right now but if my memory is correct it has the thermostat coming off the end not the top, so must be the early one
 
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