I just replaced my Oberdorfer raw water pump on my Catalina 30, same pump as before. Never had any issues with previous pump, but the weep hole had just started weeping so I figured better change it now. Worked fine for a few days, then it stopped and I found that the impellor was "spun". The shaft and inner part would spin, but the rubber didn't move. Scratched head, replaced the impellor, worked fine for a few days. Now it intermittently stops spitting water out the exhaust. I start troubleshooting by pulling hoses and running the engine all the way from the pump to the exhaust inlet. Everytime I pull the hoses it is pumping fine. Heat exchanger is also only 100 hrs old.
I've started to think there is some type of air block in the system. This could keep the water from pumping until I pull the hoses and relieve the pressure. I reckon enough back pressure could've led to the initial impellor spinning, because this all has to be related somehow. I've taken the impellor cover off and bumped the starter, impellor spins fine now. The raw water system is open, so I'm not sure how water could get trapped. I've checked and replaced any problem hoses. I'm not entirely clear on how the aqua lift muffler works so maybe that? Any thoughts would be greatly appreciated!
I've started to think there is some type of air block in the system. This could keep the water from pumping until I pull the hoses and relieve the pressure. I reckon enough back pressure could've led to the initial impellor spinning, because this all has to be related somehow. I've taken the impellor cover off and bumped the starter, impellor spins fine now. The raw water system is open, so I'm not sure how water could get trapped. I've checked and replaced any problem hoses. I'm not entirely clear on how the aqua lift muffler works so maybe that? Any thoughts would be greatly appreciated!