Generator Cooling Flow issue

[FOADIAC]

My unloaded NextGen keeps tripping offline for what I believe is a cooling water problem. Symptom: no cooling water flow seen exiting to sea from salt water side. Action taken: my diver cleaned the inlet guard on the hull, stuck a wire brush up into the inlet, felt no obvious blockage. with generator off, opened strainer and confirmed sea water was flowing out of strainer and into bilge. closed inlet valve, cleaned strainer. Replaced impeller, replaced impeller belt. Started generator and it tripped off repeatedly after 2-3 minutes. Confirmed no sea water exiting. I haven't taken apart the hoses downstream of the cooling pump, that's my next step. Am I missing something obvious? Any suggestions greatly appreciated.

 

[C lectric]

Read my tome attached. It covers a lot of possibles for your troubles. THen ask questions and maybe we can help.

 

[FOADIAC]

Thanks. I have an unusual noise from the generator exhaust which connects to your comment on water dampening exhaust sound. Now I just have to figure out where the raw water flow is blocked.

 

[Comodave]

Be careful when running it without water flow, depending on your exhaust system you might melt some hoses.

 

[Pete Meisinger]

Really sounds like an air lock. Did you recently change any hoses or allow air into the system when you changed the impeller? When you changed the impeller did you get a lot of water out of the seawater side, you should have. I once used air pressure to blow from the intake end back through the water pickup. Resistance was felt at first then bubbles coming up the side of the hull. Give it a try

pete

 

[FOADIAC]

It sat idle for a few months over the winter. I had no water leak out when I broke the seal on the impeller cover though the strainer was full of sea water, the impeller is at a higher elevation than the strainer though so when one cleans the strainer, sea water down stream of it flows backwards and drains the impeller inlet hose. I'll break out the air compressor and confirm that I have a clear path to the water pick-up from impeller output, then I'll prime from impeller output back to strainer. We'll see how that works. Thanks all.

 

[Ski in NC]

If pump is worn or impeller a bit undersized, it will not pull a prime. Fill pump outlet with some Dawn and that may help get a prime going.

 

[FOADIAC]

Never thought of that one. Thanks.