My Pearson sailboat runs a Yanmar 2GM20 that's cooled with raw water.
Here's my problem: upon starting the engine, water usually starts flowing out with the exhaust. After a few minutes post-start, it STOPS flowing out of the exhaust. Then after several minutes (and tweaking up the throttle a bit) water starts flowing out the exhaust again. I thought that this was normal (i.e. I thought a thermostat regulated flow of cooling water) until an overheating light and alarm went on the other day when water wasn't flowing out the back. While returning back to the marina, of course, after a "burp" exhaust water started flowing out, the temp came down and the alarm/light went off. It doesn't seem like a blockage since once it burps, water flows with the exhaust like there's no tomorrow. Here's what I'm going to do but I'd like to know if I'm missing anything:
1) Check raw water seacock and ascending piping to pump
** Raw water strainer is not the issue
2) Replace the impeller
3) Clean antifreeze/coolant reservoir
4) Cycle and replace the antifreeze/coolant
5) Replace the thermostat
Any suggestions or past experience with a similar issue?
Thanks!
Here's my problem: upon starting the engine, water usually starts flowing out with the exhaust. After a few minutes post-start, it STOPS flowing out of the exhaust. Then after several minutes (and tweaking up the throttle a bit) water starts flowing out the exhaust again. I thought that this was normal (i.e. I thought a thermostat regulated flow of cooling water) until an overheating light and alarm went on the other day when water wasn't flowing out the back. While returning back to the marina, of course, after a "burp" exhaust water started flowing out, the temp came down and the alarm/light went off. It doesn't seem like a blockage since once it burps, water flows with the exhaust like there's no tomorrow. Here's what I'm going to do but I'd like to know if I'm missing anything:
1) Check raw water seacock and ascending piping to pump
** Raw water strainer is not the issue
2) Replace the impeller
3) Clean antifreeze/coolant reservoir
4) Cycle and replace the antifreeze/coolant
5) Replace the thermostat
Any suggestions or past experience with a similar issue?
Thanks!