Thanks David. So yesterday I replaced the impeller. It was in bad shape. About a third of the blades had broken off. Unfortunately, I was able to recover only about half of them. How serious of a problem is this? How do I go about finding the missing ones? A few more questions and observations: Extracting and replacing the impeller was no easy matter. This is a 1989 boat with a Sherwood pump. There was no way of removing the impeller without also pulling the shaft, even after removing the snap ring. Once the shaft/impeller assembly was out it took some hefty pulling to get the impeller off the shaft, and it took a couple of firm taps with a hammer to get the new one on. Is this unusual? When I reinstalled the shaft with the new impeller, the impeller protruded about a quarter inch outside the pump casing, Eventually, by tightening the cover screws, I managed to stuff it all back in. Is this normal? And finally, when I initially removed the cover there was no gasket to be found. Maybe the old one had disintegrated over time. In the box with the new impeller was a paper "gasket" which initially I installed. Later, when the pump leaked like crazy after I opened the sea water inlet, I realized that the paper was probably a template, which I then used to cut a cardboard gasket. Is that the way it is supposed to be? I guess I assumed there would be a rubber gasket. Jeff Sheler s/v Windsome Portsmouth, VA _____
From: [email protected] [mailto:[email protected]] On Behalf Of David Savlin Sent: Thursday, July 30, 2009 12:32 PM To: [email protected] Subject: Re: [IC27A] Universal M-18 heat exchanger I agree with jm_wilhelm -- having realized we ran for 7 years on a single impeller, and noticing the engine temperature rising on our winter haul-out transit, we discovered half the impeller blades had broken off. Lucky for us, we were able to account for each blade upon replacement. It is generally recommended to replace the impeller annually given how cheap and easy it is, though I personally believe every 2 years or 50 hours of engine runtime is probably sufficient. Woe be you if the broken impeller blades get sucked into the heat exchanger, or worse, a manifold inside the engine. I'll note that engine temp rose by only around 20 degrees owing to half the impeller blades still being intact at replacement. On a related note, is there a zinc on the heat exchanger? How can I find it? Persephone ('88 hull 6480) has always run in freshwater, is it true that zincs tend to degrade slower than in saltwater? David On Thu, Jul 30, 2009 at 8:20 AM, <jm_wilh...@yahoo. <mailto:jm_wilhelm%40yahoo.com> com> wrote: > > > If your having slight overheating issues check your impeller since it might > need replacing...or check to see if you raw water intake isn't gunked up. > Those would be more likely causes > > -----Original Message----- > From: "Jeffery Sheler" <jshe...@cox. <mailto:jsheler%40cox.net> net <jsheler%40cox.net>> > > Date: Thu, 30 Jul 2009 13:08:58 > To: <ic...@yahoogroups. <mailto:IC27A%40yahoogroups.com> com <IC27A%40yahoogroups.com>> > Subject: [IC27A] Universal M-18 heat exchanger > > How often should one clean out the heat exchanger on the M-18, and what is > the correct procedure for doing so? I've noticed that the engine is running > a little hotter than normal lately and I'm thinking it may be time. Thanks > in advance for your advice. > > Jeff Sheler > s/v Windsome > Portsmouth VA > > [Non-text portions of this message have been removed] > > > [Non-text portions of this message have been removed] [Non-text portions of this message have been removed]
