The exhaust gas can rise to significant temperatures that may damage the hose in a 5 minute run. You kinda got ahead of yourself with the antifreeze and impeller removal before changing the oil. If you have less than 50 hours on the oil, I'd leave it in place. Otherwise, put the impeller back and run her with water while heating up before changing the oil.
As far as the number of blades is concerned, I suspect that the increase in vanes from 6 to 10 may actually decrease the amount of flow as the extra vanes may displace more water within the pump cavity. I'd go back to the prescribed impeller. Those design engineers are paid the big bucks for a reason. Rich Knowles INDIGO - LF38 Halifax, NS -----Original Message----- From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Eric Frank Sent: November 5, 2012 15:38 To: cnc-list@cnc-list.com Subject: Re: Stus-List water pump impellers Not quite related to Rich's comment, but close. After hauling this fall, I took out the raw water impeller after running antifreeze through the system as has been well described on this list. I would like to run the engine to warm it up before changing the oil and filters. The fresh water cooling system will cool the engine fine until it is warm, but will I damage the exhaust system by not cooling the exhaust with the "raw" water? It will probably take 5 minutes or so of running to warm up the engine oil. Also, last spring I replaced the impeller with a 10 bladed one, whereas the ones I have used before have only 6 (I think) blades. Any reason to favor one over the other? It seemed to work fine. Eric Frank Cat's Paw C&C 35 Mk II Mattapoisett, MA > Harking back to a discussion a few weeks back about raw water pump impellers, I ran into another one yesterday on an overheating 4kW genset that looked perfect but had the brass drive hub separate from the rubber vanes. So, if you are trying to decide whether or not to replace an impeller, I suggest including in your examination an attempt to rotate the vanes on the hub. The unit looked pretty serviceable other than that. > > Rich Knowles > INDIGO LF38 > Halifax, NS. _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com CnC-List@cnc-list.com _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com CnC-List@cnc-list.com
