Actually, the area of a 1 1/2" circle is only 55% of the area of a 2" circle, so the exhaust is only about half of what is required. Area = Pi x Radius squared
A = π r 2 3.14 sq.in. = π 1" 2 *1.7sq.in <http://1.7sq.in>. *= π (.75") 2 On Mon, 14 Sep 2020 at 08:17, David Risch <davidrisc...@msn.com> wrote: > Did you inquire of Westerbeke about reducing exhaust flow by 25%? Sound > like it may be a lot… > > > > *From:* Kevin Burke <kjbw...@earthlink.net> > *Sent:* Sunday, September 13, 2020 10:32 AM > *To:* cnc-list@cnc-list.com > *Subject:* Stus-ListOverheating-new installation > > > > I just replaced an old Westerbeke with a new/old stock Universal m3-20b. > It fires up with no problem, runs smoothly atnd spits what seems to be the > appropriate amount of water out of the exhaust, but I was testing it by > idling it about 800 rpm and after 20 minutes or so it overheats to 200 > degrees and the overheat alarm goes off. It has a new exhaust elbow and > new impeller, no signs of corrosion anywhere, and only about 1.2 hours on > the hour meter. It is about 20 years old, ordered for a swap but not > used. It was stored properly indoors and has fresh coolant. I think I > bled the coolant properly-there is an overflow tank and a bleed valve on > top of the thermostat, which is at the front high point on the engine. I > ran it with the valve open until there was a steady stream of coolant > coming out. My original thought was that there was air in the system or a > bad thermostat. I tried running it without the tstat and it did the same > thing. It seems hotter above the thermostat than on the sides below the > head gasket. Any thoughts? The muffler is fairly new as well and I did > not see any buildup in the pipe. I had to install a fiberglass reducer > from 2 inches to 1 ½ shortly after the exhaust elbow to feed it to the > existing muffler. Could it be excessive back pressure from the reducer? > > > > Kevin Burke > > Mark I 35 > > Galesville, Md. > > > > Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for > Windows 10 > > > _______________________________________________ > > Thanks everyone for supporting this list with your contributions. Each > and every one is greatly appreciated. If you want to support the list - > use PayPal to send contribution -- https://www.paypal.me/stumurray > >
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