exhaust riser

[kevMar]

well the exhaust riser finaly broken leaving me stranded. Lucky for me  have tow boat and the 4 hour tow home was covered.  NOW where should i try to get a new one or have the old one welded. where would one find a replacement 1988 34  universal mxp25  thank for your help

[Ron Hill]

kev : You probably can get a new exhaust riser made locally down there in New Bern. That would be simpler than trying to send it off to Catalina and having them duplicate it.  

Before you take off the old one read the articles that I and others have written on replacing that exhaust riser.

If you want a new replacement engine? you need to read my Mainsheet article on installing a M25XPB.  A few thoughts
 

[Stu Jackson]

You are now truly a C34 skipper!

Here's my story:  http://www.c34.org/mainsheet/pdf/Feb_2004.pdf

Lots more in the tech wiki.

Many different ways to replicate the little bugger.  Don't forget the hump hose.  Do NOT use the hose loop described in that article - it doesn't work and chafes on itself.  I removed and replaced it with hump hose after the "helper" (who really did all the dirty work) left.  

[Ron Hill]

kev : Glad Stu jostled my brain as I'm not too sure that the articles mention the hump hose (you get it from Catalina).  It Saves all engine vibration from being transmitted to the inlet on the muffler!!

Also make sure that you replace the wire reinforced hose from the HX antisyphon to the nipple on the riser with nylon reinforced hose.

[John Langford]

I am about to reattach my rebuilt exhaust riser which was leaking at one of the welds. Does anyone know if the original grey gasket between the manifold and the riser needs to be replaced each time you remove the riser? It looks in good shape.

I am not sure exactly how the exhaust Tbolt clamp works but I gather as you tighten it the end of the riser is pulled against the back of the manifold. If that is the case and the gasket is in reasonable shape my assumption would be that I can reuse it.

Any views gratefully received.

[Ron Hill]

John : You have an M35BC engine that has a completely differant riser connection than the M25/XP engines.
 
You can try using the reusing that old gasket, but you'll need to check it for exhaust leaks after you get it reinstalled.  Just make sure there is no debris or scratches on the face of the riser mating flange.

As far as that Exhaust Elbow clamp (#036541) goes - just back off the screw, slip it on so the clamp catches the lips of both the riser and the exhaust manifold (with the gasket #036425 in the middle) and screw it down until it's snug/tight.  As I mentioned you'll have to check it for leaks with the engine running!! I don't know the price of that gasket, but it's definitely a Westerbeke part.

A few thoughts

[Kyle Ewing]

Kevmar--I replaced my this spring.  Based on my dissection of the old, the pipes and elbows seem to be common.  I'd think most weld shops can put on the water injection nipple for you.  The heat insultion IS A MUST.  It's a fire hazard without it. 

I had Catalina make a new one because I had time.  Knowing what I know now, if I had a failure on a cruise I'd take the old to a pipe supply store and find or have cut and threaded pipe to match, have a weld shop put on the nipple, and get fiberglass exhaust insulation from an auto-parts store.

IMPORTANT REGARDING RISERS:  When talking to Catalina about my boat, they confirmed what has been stated here many times.  Exhaust riser failure is one of the most predictable failures to occur on the boat.  They told me even though I was in fresh water for the past 21 years and my pipe was stainless steel, it would fail sooner or later.  With the new one I don't have to worry for another 15+ years.

[John Langford]

Found a new Universal riser gasket for $6. It didn't look much more lively than my old one but I bought it anyway.