View Full Version : Pressure Relief Valves on Chris Craft motors

12-11-2006, 08:21 AM
"The Pressure Relief Valve is a device that is normally “out of sight, and out of mind” on a Chris Craft. This is the Pressure Relief Valve (see photo link), http://www.network54.com/Forum/424840/message/1164411296 ("]http://img.photobucket.com/albums/v472/Dogsharks/Sea%20Skiff/DSC00965.jpg"[/url]

and it is used on just about all Chris Craft V8 motors from the late 1950’s onward. The Sherwood Brass sea water pumps have a great pumping capability and at top speeds they are able to over-pressurize the motor. In order to vent off excess pressure, Chris Craft devised a simple automatic method of bleeding excess pressure directly into the discharge riser. These valves faithfully provide service for many years, but they have one flaw, and that is the fact that over time, they are able to be compromised with crud and small pieces of debris passing harmlessly through the system. In the event a pressure valve gets stuck in the open position, for instance, incoming cooling sea water can be short circuited directly into the exhaust system and only a portion of the needed low speed water stream will reach your motor block. This can contribute to low speed overheating.


If you have a motor that is getting hot at low speeds, it could be because your PRV is being held open, or your water impeller is worn or coming apart, or the cam inside your water pump is very worn, or there may be debris from a destroyed water pump or other source, somewhere in a critical location in your water delivery system (the transmission oil cooler on some models is a likely location for collecting debris).

Hope this helps someone in the Chris Craft contingent !

Regards, Dogsharks"

12-12-2006, 06:31 AM
Good info! Suggest you add your post to the Chris-Craft Owners site (if you haven't yet).


12-12-2006, 09:55 AM
"Hello Jeff, thanks for the note and the reference, but what Chris Craft Owner's site are you mentioning? Please lemme know where, and I'll post there as well. My motivation is 100% non commercial, and I'm just trying to help Chris Craft guys. I posted this on the Chris Craft Antique Boat Club site, and got some good comments back. Regards, Dogsharks"

12-13-2006, 10:23 AM
"http://www.yachtforums.com/forums/forumdisplay.php?f=223 ("")"

12-19-2006, 02:45 PM
"Thanks for the reference, consider it done. Chris Craft guys need to stick together and share info! :-)