TWL: Lehman Exhaust Question
Subject: TWL: Lehman Exhaust Question
From: Andy Clark (slowboat@XXX.XXX)
Date: Tue Mar 13 2001 - 23:38:45 EST
Ron Jones wrote:
snip......"On a recent trip the port exhaust hose burned through at
the end of the
> elbow. Engine temperature was normal." snip...
---------------
Two areas you should look at:
1. Is the fitting that introduces water into the exhaust elbow
(partially) plugged with deposits? Obviously no or reduced water flow will
cause excessive temps in the entire exhaust system. The rubber hose is the
first to go.
2. Is the diffuser shelf inside the elbow rusted through? You'll
need to remove the elbow to check this. If it is, even though you are still
getting good water flow, the water is falling directly to the bottom of the
exhaust passage and the hot gasses are passing above it, again, causing the
rubber hose to burn through. Anyone with a '70s or 80's Lehman should check
this shelf yearly because of this age-related deterioration. Even if the
shelf looks good, give it the "screwdriver test". That is, try to drive a
screwdriver through the shelf using sharp raps from a hammer. Sometimes the
shelf looks good, but is rotten with corrosion, just waiting for the right
(wrong?) time to perforate.
Hope this helps.
Andy Clark
ANTARES
CHB 34 with a new exhaust elbow <g>
Homeport, Everett Washington
