"Mid Size Power Boats": A Guide for Discreminating Buyers - by David Pascoe

PHOTO LIBRARY

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Exhaust Risers

Page One

Photos by David H. Pascoe, Marine Surveyor

 

RiserMerc.JPG (34640 bytes)
Mercruiser 4.2 V6 riser. Arrow shows where corrosion hole occurred. It doesn't take much corrosion to block these small water passages. Note that the passages top and bottom only have a tiny hole where it met the larger passages on the manifold. Hard to figure this one???

 

RiserMercV8.JPG (40794 bytes)
Merc 350 riser. Notice the difference, especially the width of the gasket surfaces between the openings. This one had been cleaned of scale and put back in service. That didn't stop it from leaking and ruining the engine, which it did.

 

Crus454FWCriser.JPG (68506 bytes)
This Crusader 454 riser system is 12 years old. That's because the riser is closed system cooled. Naturally, it costs more money. The water induction elbow is behind the coolant bottle and is a lesser expensive throwaway. Notice the oil filter adapter where you can easily reach it.

 

RiserCrus.JPG (27795 bytes)
Crusader riser, salt water cooled. This design uses a steel insert ring with the water passage all around it. It too, is narrow and over time became completely blocked with scale.

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Exhaust Risers Photos : Page Two

First posted October 23, 1998 at www.yachtsurvey.com.

Posted January 24, 1999

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About Author:
David H. Pascoe is a marine surveyor (retired) with 40 years' experience.

He is author and publisher of power boat books:

"Mid Size Power Boats"
"Surveying Fiberglass Power Boats" 2E
"Buyers' Guide to Outboard Boats"
"Marine Investigations"

Visit  yachtsurvey.com  for more than 160 online articles.

David Pascoe's biography

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