Manifold Change

[dremison]

Up front:
-I’ve owned the boat 4 years and have no idea when the manifolds and risers were changed last.
-Spent many years in salt water in VA Beach, then 2 in brackish water in MD.
-It’s clear from the attached pictures that they have been partially changed at some point ( looks like OEM on port side, after market on starboard).
-Shows visible signs of deterioration on the exterior of the aftermarket parts.
I ordered OEM replacements yesterday and I have two real questions:
1. Spending 3 grand wasn’t an overreaction to this kind of deterioration, right?
2. When I have it apart, is there anything else I should replace/inspect in the meantime?
View attachment IMG_0509.jpeg

 

[Scott06]

Up front:
-I’ve owned the boat 4 years and have no idea when the manifolds and risers were changed last.
-Spent many years in salt water in VA Beach, then 2 in brackish water in MD.
-It’s clear from the attached pictures that they have been partially changed at some point ( looks like OEM on port side, after market on starboard).
-Shows visible signs of deterioration on the exterior of the aftermarket parts.
I ordered OEM replacements yesterday and I have two real questions:
1. Spending 3 grand wasn’t an overreaction to this kind of deterioration, right?
2. When I have it apart, is there anything else I should replace/inspect in the meantime?
View attachment 407133View attachment 407134

You are right to change them and zero the milage given salt water use. 5-7 years change out is norm, if it leaks water into exhaust easy way to loose an engine .

would look for signs of water intrusion into exhaust and exhaust ports on head. Check the exhaust flappers in top of wye pipe.

 

[Scott Danforth]

I ordered OEM replacements yesterday and I have two real questions:
1. Spending 3 grand wasn’t an overreaction to this kind of deterioration, right?

View attachment 407134

BTW, I would have bought Barr manifolds vs the mercruiser manifolds made by Barr and saved yourself about $2 BOAT units.

 

[dremison]

BTW, I would have bought Barr manifolds vs the mercruiser manifolds made by Barr and saved yourself about $2 BOAT units.

Good to know - I will try and remember that in 7 years when I have to do this again. Thank you!

 

[bajaman123]

Are you changing manifolds AND risers or just the risers?
Pray to whomever you trust in that you don't snap off any bolts...
Good luck!

 

[Lou C]

You might try warming up the engine, then drain the manifolds and then use an impact to break the bolts loose. The ones you’re most concerned with are those holding the manifolds to the cyl head, if the bolts for the spacers/elbows won’t come out or break you can remove the manifold & elbow as a unit. Last struggle will be the rubber exhaust hoses, loosen the clamps first then shove a long thin screwdriver in between the elbow & hose wiggle it around & spray silicone spray in there to get it to come apart. Same for the lower hoses. Spray in the joint between the 90*pipe & lower hose, and spray on the Y pipe so the hose can slide down to release the 90* pipe…..
I second using BARR MARINE for your exhaust kit. Just remove the paint from all sealing surfaces and check for flat & level. Then give them one nice brushed on coat of Rustolium because the paint BARR puts on them won’t hold up in salt water….

 

[ESGWheel]

While I too used screwdrivers for years to break the stuck hose, a few years ago I got a set of these (link) and never used anything else. The one in the bottom pic has an offset that makes it easy to get around the circumference. And they are inexpensive.

More: there are some tips to replacement these that include using two cut off Riser Bolts threaded into the head to help keep the gasket in place and ease the installation of the heavy exh header. Also, while agree to take paint off and ensure flat on the new header, same is true for the head. And to clean it up, need to preclude debris getting into the cylinders by using rags stuffed into the ports. And best to chase the threads on the heads and more. See this link for these tips and more.

 

[Lou C]

Same I have those too!
Forgot to mention I use 2 headless bolts to hold the manifold in place with the gasket

 

[dremison]

Update: all bolts broke loose without issue. Bullet dodged there.
Alternate problem: the risers that came in the kit are not a match w the ones on the boat. The boat currently has 1.7s, which these are not.
Is there a better solution to this than returning and repurchasing the match? Maybe an extended hose on the boots in the back?
Thank you all so far!

 

[cyclops222]

Headless bolts on installing a starter or intake manifolds.
Anything awkward or heavy on any machine.

 

[Lou C]

headless bolts.....take the manifold bolts to a hardware store, buy the same thread pitch bolts but longer, cut the heads off and cut a slot in the end to make it easy to remove with a large screwdriver, makes it MUCH easier.

 

[Lou C]

Update: all bolts broke loose without issue. Bullet dodged there.
Alternate problem: the risers that came in the kit are not a match w the ones on the boat. The boat currently has 1.7s, which these are not.
Is there a better solution to this than returning and repurchasing the match? Maybe an extended hose on the boots in the back?
Thank you all so far!

Those spacers look like you could clean them up & reuse them….

 

[dremison]

Those spacers look like you could clean them up & reuse them….

You think so? More pics attached - tell me what you think. This is from the starboard side, which have the most visible deterioration.

 

[Scott06]

Update: all bolts broke loose without issue. Bullet dodged there.
Alternate problem: the risers that came in the kit are not a match w the ones on the boat. The boat currently has 1.7s, which these are not.
Is there a better solution to this than returning and repurchasing the match? Maybe an extended hose on the boots in the back?
Thank you all so far!

I think they use a longer down turn after the elbows to match the riser which arent cheap as I looked into it a few years back.

your bolts wont be long enough either so you are probably best to return and get the same size as you took out (assuming they were the correct height above waterline originally)

 

[dremison]

Alright, got it all reassembled and it fired right up. Lower unit seems to be cycling water but it’s not getting to the manifold. It started to overheat and when I pulled the plug by the thermostat, there was no water flow. The water coming out of the exhaust wasn’t hot, either. Seems like there is a suction problem. All my bellow clamps and tubes are tight with no visible signs of leaks. Any ideas where to look next?

 

[Scott Danforth]

Are you running on muffs?

Or attempting to pull from a bucket.

Because pulling from a bucket requires the bucket to be big enough to float the whole boat.

 

[dremison]

Are you running on muffs?

Or attempting to pull from a bucket.

Because pulling from a bucket requires the bucket to be big enough to float the whole boat.

Hi Scott,
I’m on muffs from a hose.

 

[dremison]

When I winterize, I manually fill the block w antifreeze by pulling all the hoses by the thermostat - any chance that might get the water circulating a bit better?

 

[Scott06]

Alright, got it all reassembled and it fired right up. Lower unit seems to be cycling water but it’s not getting to the manifold. It started to overheat and when I pulled the plug by the thermostat, there was no water flow. The water coming out of the exhaust wasn’t hot, either. Seems like there is a suction problem. All my bellow clamps and tubes are tight with no visible signs of leaks. Any ideas where to look next?

Take the hose off the thermostat housing that brings water up from the outdrive. Should get 3-4 gpm. If not it’s from there back to outdrive. Also make sure the muffs are not impeding the water flow to the drive.

 

[dremison]

Well, this did the trick. Holding firm at 165.

When I winterize, I manually fill the block w antifreeze by pulling all the hoses by the thermostat - any chance that might get the water circulating a bit better?