Thanks! On Mon, Jun 19, 2017 at 6:26 PM Dreuge via CnC-List <cnc-list@cnc-list.com> wrote:
> Joel, > > I have had some experience with a Yanmar 2QM15 which was in my old C&C 29 > mk1. The 2QM15 manual states that at 2000RPM, the raw water pump should > deliver 400 l/hr (which is about 1.75 US Gallons/minute). It should be > easy to bypass the raw water just before it enters the mixing elbow and > measure the flow rate. If the flow rate is fine, then the problem may be a > clogged mixing elbow or even a bad thermostat(see comment below). If the > flow rate is low, then check for free flow of the input line to the water > pump. That is, with engine off, disconnect input hose from pump, lift the > end above the waterline, open seacock, and lower hose into a bucket to let > the water flow in. > > If the input flow rate & pump impeller are fine whereas the engine output > flow is low, then you can look into pickling the engine as suggested. But > to be honest, pickling the engine with vinegar works well for yearly > maintenance, but likely won’t remove serious engine scale. If you suspect > a serious scale problem, then use something like Barnacle Buster. It is > best to set up a circulation loop: put 1 gallon BB in a 5gal bucket, use a > cheap Walmart-like bilge pump to pump the BB into the engine (after raw > water pump), take a hose from the engine output back to the bucket, and the > let it run run run. > > Note that a bad thermostat can cause the engine to overheat. These can be > easily removed and tested. DO NOT run the engine without a thermostat as > the thermostat not only allows engine water to flow when open, it also > closes the raw water engine bypass as it opens. > > Also, be sure that the engine is actually over heating. I once spent some > time tracking down an overheating alarm problem when in the end it was a > bad temperature sender unit. > > Scale can be a real problem. Here is a link to Sailnet post I wrote some > time back regarding rebuilding a 2QM15. > > > http://www.sailnet.com/forums/gear-maintenance/90991-yanmar-2qm15-rebuild.html > > > Here is a direct link to photos. It was amazing how much scale was in > the engine. Ssee photos 12 &13 which shows the inside of the block after > removing the cylinder sleeves. It a big pile of crud. > > https://www.flickr.com/photos/dreuge/sets/72157631067396554/ > > > > > > > > - > Paul E. > 1981 C&C 38 Landfall > S/V Johanna Rose > > http://svjohannarose.blogspot.com/ > > > > > On Jun 19, 2017, at 11:24 AM, cnc-list-requ...@cnc-list.com wrote: > > From: CnC-List [mailto:cnc-list-boun...@cnc-list.com > <cnc-list-boun...@cnc-list.com>] On Behalf Of Joel Aronson via CnC-List > Sent: Monday, June 19, 2017 8:25 AM > To: cnc-list@cnc-list.com > Cc: Joel Aronson <joel.aron...@gmail.com> > Subject: Stus-List 2GM15 salt water cooled engine overheating > > All, > > The J30 I race on is overheating. It's not the impeller. The engine is > 35 years old and salt water cooled. I pulled the hose off the elbow and > blew into it. There did not seem to be any restriction. (Does that mean > anything?). What's next? Thermostat? Clean heat exchanger? Elbow? > > Thanks. > > Joel > -- > Joel > 301 541 8551 > > _______________________________________________ > > This list is supported by the generous donations of our members. If you > wish to make a contribution to offset our costs, please go to: > https://www.paypal.me/stumurray > > All Contributions are greatly appreciated! > -- Joel 301 541 8551
_______________________________________________ This list is supported by the generous donations of our members. If you wish to make a contribution to offset our costs, please go to: https://www.paypal.me/stumurray All Contributions are greatly appreciated!
