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View Full Version : Replace Rusty Risers and Manifolds?


51timber
12-11-2012, 09:16 PM
Looking for your thoughts. Are these risers and manifolds worth saving? I am thinking not, though I have seen a past thread where they were cleaned out once and looked pretty good. My Big concern is even if I replace the risers, I don't know if I can get the bolts off for the manifolds (SEE PIC).

Since the bolts are so rusted on the manifolds, can I cut off the heads of the bolts off and then pull the manifolds off then back the rest of the bolts out with Vise grips???

If I replace the manifolds do I need a sealant of some kind along with the gaskets?

Thanks for your advice.

Bouyhead
12-11-2012, 10:10 PM
Are you running in salt water? If you are shelf life for the manifolds and risers are 5-7 years to play it safe. As far as those manifold bolts go, I've seen worse. Start soaking them a few days before with a good penetrating oil like PB Blaster, they should come out. As far as the gaskets go, I've never used them. Just a light coating of Permatex Hi Temp sealant on the block and manifold and you should be good to go. One more thing, if you are running in salt,anything that has threads should be coated with grease or NeverSeize. Good Luck!

mart_it
12-12-2012, 12:09 AM
Those Manifold's look clogged completely!!
I'm surprised your motor didn't overheat from not being cooled efficiently.
Are you running a thermostat?

It seems the right side bolt can maybe come off with a socket. I would use a punch and hammer the head of the bolts before trying to put a socket first, see what it does....if not cut the heads like you said.

If the manifolds aren't cracked why replace them? Unless your running in salt or really brackish water, I would get them cleaned and blasted, then re-painted.

51timber
12-12-2012, 05:18 AM
The boat was used in salt for the first 200 hrs. (7 years) last 2 years 95% fresh now about 300 hrs. Could I take both the risers and manifolds to a machine shop and have them clean them out and polish the mounting surfaces? Or should i just replace everything?

Bouyhead
12-12-2012, 05:41 AM
The boat was used in salt for the first 200 hrs. (7 years) last 2 years 95% fresh now about 300 hrs. Could I take both the risers and manifolds to a machine shop and have them clean them out and polish the mounting surfaces? Or should i just replace everything?

As mart-it said you could clean the manifolds and squeak a little more time out of them, but if it was my boat I would start fresh with new manifolds & risers. Think about changing out the thermostat too and don't be suprised if the thermostst housing crumbles in your hand when you remove it.

51timber
12-12-2012, 07:17 AM
Ok will do. Being green but willing to get in there and do it myself, where is the thermostat housing?

mikeg205
12-12-2012, 09:03 AM
You can also soak them in a bath of evaporust. www.evaporust.com - I cleaned up my 17 year old fresh water manifolds and risers and even ran it thru the block...it's non corrosive... see http://www.mastercraft.com/teamtalk/showthread.php?t=32234&highlight=work&page=193 post 1924. Other thread has test on penetrating oil - 50% ATF + 50% acetone showed best results.

+1 on the duty cycle on the manifold/risers - but might be worth talking a close look at the channels in manifold/risers if cleaned up.

Regarding the evaporust - I used a gallon to get my results. You could use it to at least remove the rust from the bolts on the manifold before you applying penetrating solution.

My plan is another gallon of evaporust thru manifold in risers during after next season.

Your manifolds/risers might be a cheaper replacement then buying enough evaporust to fill a vat. But I would at least get a few gallons and run thru block to clean out water jacket.

mikeg205
12-12-2012, 09:07 AM
what year boat and which motor?

51timber
12-12-2012, 12:06 PM
2003 x30 mcx motor

swardco
12-12-2012, 12:13 PM
I don't think this is a thread-jack, but here goes.

My boat is a 1991 Prostar 190, freshwater only. Showing some rust stains at "leaking" down from the joint where the risers attach to the manifolds. 99% sure these are the original manifolds and risers.

Sounds like I need to at very least pull the risers and see how things look. I shouldn't be surprised if I need to replace 20+ year old risers/manifolds???

mart_it
12-12-2012, 12:55 PM
For those seeing rust stains leaking from the riser gaskets, just clean them up, re-surface the mating surfaces using a wire brush or sand paper and just re-install them using new gaskets and a good paste compound.

51timber
12-12-2012, 11:38 PM
I will call the dealer, but just out of curiosity...What do new risers and exhaust manifolds cost?

east tx skier
12-12-2012, 11:44 PM
For those seeing rust stains leaking from the riser gaskets, just clean them up, re-surface the mating surfaces using a wire brush or sand paper and just re-install them using new gaskets and a good paste compound.

Yep. Some new gaskets with some light sanding will do fine. For fresh water, the risers will last a long time, even if there is rust on outside of the exhaust manifolds.

Bouyhead
12-13-2012, 06:23 AM
I will call the dealer, but just out of curiosity...What do new risers and exhaust manifolds cost?

About $750 to $850 depending on where you buy. Lot's of online discount retailers:
http://bpi.ebasicpower.com/index.php
http://www.skidim.com/

Watch out for shipping charges though, lot's of weight there.

Do you have a local retailer? Sometimes they will match the online guys and you'll save on the shipping charges.

tex
12-13-2012, 08:46 AM
Rusty Risers-Isn't he an old skool porn star?

51timber
12-21-2012, 11:03 PM
Well I have bought all the new Risers and Exhaust manifolds.
Only one problem. I can't get the old exhaust manifolds off. I have ground down the bolts but they are stuck on there good. Any suggestions for getting them off???

mikeg205
12-21-2012, 11:17 PM
pour penetrating oil on the seam of the mating surface or the 50/50 mix of acetone/atf - let it sit a few hours - re-apply oil. Also apply oil to bolt surface. I would do that for a day or 2. Then get a small steel mallet - and give a few good whacks...IMO Can you post some pictures of how the manifolds look?

51timber
12-22-2012, 08:17 PM
Will do. That sounds good. I am amazed at how stuck on they are. I didn't think of the penetrating oil. Will do. at this point the exhaust manifolds are toast. All the grinding we have done has eaten away at them. Still I will post some pics though.

Thank you.

mikeg205
12-22-2012, 11:19 PM
The next thing I would do is seek the advice of an engine shop...any luck searching the old threads?
..maybe someone will chime in after Christmas... sorry your issue on this... I am sure you are very frustrated. Good luck..

CC2MC
12-22-2012, 11:44 PM
Mike205, is this something that you have done to yours before?

mikeg205
12-22-2012, 11:56 PM
Mike205, is this something that you have done to yours before?

As Kyle stated in another post my OCD on my boat is 13 on a scale of 10. I inspect my riser manifolds every season. My riser/manifolds are approaching 18 years old. I have yet to pull off my exhaust manifolds because they do not show any sign's of seeping or leaking. I obsess about the oxidation occurring in the water jacket of my engine manifold and risers.

I have been treating my manifolds bolts every season to maintain them. At one point I will have to pay the piper and pull the manifolds. But until then oxidation and I will be battling it out.

If you can't get the manifolds to budge with simple means...it's time to get the professionals involved. The only thing I can think of is that there was some water intrusion or oxidation that worked it's way down the mating surfaces...now it needs to be broken loose. I would seek professional advice before applying to force or a strong blow from a hammer to brake it loose. Any boat owner should be ready to fork over $1K to repair an old engine. Maybe PM JIM at BAWS to get an opinion.

Madcityskier has over 2K hours on his original engine... my goal is to beat him.. :D

CC2MC
12-23-2012, 01:18 PM
Madcityskier has over 2K hours on his original engine... my goal is to beat him.. :D

And your hour count is what at this point?

mikeg205
12-23-2012, 05:22 PM
And your hour count is what at this point?

675 - I have a long way to go ;)

51timber
12-25-2012, 08:25 AM
We got them off. We tried the pry bar hammer and all. I got nervous. I was afraid of damaging or cracking the block. (we never hit the block)

We used a pota power and they came right off. Will add the new manifolds and risers this week.

So yesterday I pulled the trigger! Took all of the interior out and decided to have it all redone. By the time I'm done it'll look new.

Should I start a new thread under refurbishing?

mikeg205
12-25-2012, 12:14 PM
We got them off. We tried the pry bar hammer and all. I got nervous. I was afraid of damaging or cracking the block. (we never hit the block)

We used a pota power and they came right off. Will add the new manifolds and risers this week.

So yesterday I pulled the trigger! Took all of the interior out and decided to have it all redone. By the time I'm done it'll look new.

Should I start a new thread under refurbishing?

Congrats... pota power? (porta power jack?) I would be nervous too..giving it a good whack...but I guess that's what it takes...too bad you did not have someone video taping... ;)