Help removing exhaust riser

[redbeard1]

Hello,


Our boat, built in 1993, has a Volvo 2003b engine. We purchased the boat 1 year ago. The PO (and us) have used the boat exclusively in fresh water.


We would like to inspect the exhaust riser for preventive maintenance but cannot remove the riser.


I removed 4 bolts (blue circles in the picture) and even the retaining clip for a metal hose (yellow circle) but the riser would not budge. I hit the riser from the side with a hammer placing a wood block in between. Again, no budging. Soaked in PB Blaster and repeated above. Again, no budging. Any tips?


For those with this engine, did I miss a bolt to remove?

[Wotname]

It is possible that the riser has never been removed in the past 24 years so some persuasion might be required; code for a bigger hammer .

I don't have this engine but can you provide some leverage upwards in some fashion or perhaps wedge with a screwdriver blade between the riser and the block.

IMO, proceed carefully, adding more persuasion in small doses!

[DougR]

You have all the bolts removed, now you need a bit more umph...

DougR

[redbeard1]

Thanks all,

I'll gradually apply more force.

I have a heat gun that outputs 700 degrees. Could that help break the bond? or would it just melt the gasket and create a mess?

[Wotname]

Originally Posted by redbeard1

Thanks all,

I'll gradually apply more force.

I have a heat gun that outputs 700 degrees. Could that help break the bond? or would it just melt the gasket and create a mess?

It might help and it certainly won't melt the gasket or create a mess.

If you are brave, you could try running the engine with the bolts removed, you will soon see if the bond breaks

[ottow]

Removing an identical riser on my 1985 Volvo Penta 2002 proved to be a similar challenge.
With little space to use a bigger hammer I eventually got it loose by lifting the after end upwards, using the very stiff (still attached) exhaust hose for leverage.

Hope this helps,

Otto

[drpaoletta]

You didn't mention if you have applied penetrating fluid like PB Blaster. I had a bit of trouble detaching my exhaust flange too, and repeated doses plus leaving overnight to penetrate eventually did the trick without needing to pry. Be very careful that you don't damage the seating surface on the engine side - and have your new gaskets & Permatex ready for the re-installation.

- Good Luck!

[deblen]

I have a VP 2003. You have removed all the bolts-it's just "grown" on with rust.
Consider a SS one if you have to replace the ell
https://hdimarine.net/product/vp-sta...exhaust-elbow/
There may be other sources.

Replace the rubber rings on the copper tubing or they will leak. They are cheap.Use a battery terminal brush to scour the ends of the copper tubes & the sockets that the tubes plug into. A little smear of vaseline on the rubber ring is good also.

A link to 2003 elbow job. http://www.ybw.com/forums/archive/in.../t-433204.html

Len

[redbeard1]

Thanks again for all the ideas and links.

I applied PB blaster about a month ago to prepare for this and applied again 30 minutes before I began to hammer.

Not wanting to damage the mating surfaces, I think I will continue to apply the penetrating solution every time I visit the boat (maybe heat the area beforehand). Hopefully, by the spring the riser will just slide off .

As I mentioned, the boat has spent all her time here in Lake Michigan, water flow rate is similar to the Johnson pump spec sheet, so we do not expect to find any obstructions inside the riser - just poking around to learn our boat.

[AlanR]

For next time you need to remove it, coat the bolts, both threaded and unthreaded parts, with copper-bearing grease before reassembly. Give the bolts retaining the water pump the same treatmend, and nothing wrong with treating all bolts this way. The copper will stil be there ten or more years later, to work as a lubricant when dismantling. Magic.

[Squanderbucks]

Because cast iron is brittle you need to be a little careful about how hard you hit with hammer so you don't crack the manifold. Try heating with a torch and soaking with more PB blaster and if access to an electric or better yet a pneumatic impact driver use it. Put the impact driver on the manifold right next to the seam and activate the pneumatic hammering. Stop every so often and soak with more PB Blaster and heat again if needed.

[jimbunyard]

Originally Posted by redbeard1

Thanks again for all the ideas and links.

I applied PB blaster about a month ago to prepare for this and applied again 30 minutes before I began to hammer.

Not wanting to damage the mating surfaces, I think I will continue to apply the penetrating solution every time I visit the boat (maybe heat the area beforehand). Hopefully, by the spring the riser will just slide off .

As I mentioned, the boat has spent all her time here in Lake Michigan, water flow rate is similar to the Johnson pump spec sheet, so we do not expect to find any obstructions inside the riser - just poking around to learn our boat.

Will be an interesting experiment to see if the blaster will just 'soak it off'; I'd bet not, the gasket sealing the flange is meant to seal, not absorb...

If you want to get it off in about two minutes (after the bolts are out), the tools to use are an old wood chisel and a little hammer.

Put the business end of the chisel parallel to the sealing plane of the manifold/riser interface, beveled side toward the riser, at the corner where the bolt goes through at about a 45 to the bolt (see picture below). Tap tap tap, a little gap will open up. Go around to the next bolt and do it again (but you probably won't have to).

Should fall right off.

[flyingfin]

Step away from that engine and drop you hammer. Get a good butane torch, or hire a pro with an acetylene torch. You will need to heat the elbow, then let it cool. Then repeat this at least 10 times. Now hit it again with PB and let sit overnight, then the next day bring out the torch again, but this time with a wet rag for when the PB catches fire. Only then can you tap with the hammer. This is why marine mechanics recommend removal and inspection every 2 years in salt and every 4 years in fresh water. Gaskets are cheap

[jimbunyard]

At no point should your hammer ever strike cast iron directly. If for whatever reason you don't want to use the method I previously described, which will absolutely work every time (thems strong words bubba), use a stout piece of wood for leverage to pry the recalcitrant piece loose, or use the hammer on the wood.

It's sorta ok to pound on forged or wrought iron and steel, definitely a bad idea to beat on cast iron...

Using heat in this application is just wasting gas and contributing to global warming (ha ha)...

[Wotname]

For the OP, IMO listen carefully to Jimbunyard. If it was me , I would taking his advice.