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started both engines yesterday on the hard - knocking noise

B

bobct

Advanced Contributor
I started both 454's yesterday, I needed a break from scraping the bottom paint. My Stb engine made a knocking noise for the first 3-4 mins and then slowly went away. It sounded like it was coming from the front of the engine. I never heard it before but this lay up was about 2 months longer than last year if that made a difference.

Don't water pumps (FWC) make that kind of noise when they start to go? There weren't any leaks and I didn't notice any play but I'll check it again. It was a pretty heavy rapping, like a lifter type of sound. Once it warmed up, it sounded perfect.



Bob
 
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oil pressure jumped right up, over 40. RPM's were around 1,200 and I goosed it a couple of times and the knocking went up as well. I didn't want to run it over 1,500 for long since I was on the garden hose. I'll probably start it again over the weekend and see if it comes back.
 
OVER 1500 RPM, on the garden Hose??? If you like those pumps, I'd encourage you to NOT do that again. No normal garden hose can flow sufficient water to continuously feed a raw water pump spinning at 1500 RPM. If you need to run it above idle, I'd disconnect the raw water pump and just let the garden hose "take its place".

On the circulating pump going - my limited experience is that when their bearing fail, they rarely 'get better'. IOW, once they start to sqeak, they never stop.
 
Just for a few seconds at a time :)

At 1,200, I can see that the strainer stays full so it can tolerate quick RPM bursts. I have a direct connect fitting at the seacock so the water flow is better than the intake scoop/plunger which worked but always leaked some water which reduced the flow.

I'll have to start it and listen again. Might have been a lifter hanging up after sitting for 6 months. Was definately a knock and not a squealing sound.
 
It is probably the fuel pump actuation rod getting stuck. After the engine is warmed and the oil flows this will stop.

2nd, if the garden hose can keep up with the raw water pump, it might be time to change the impellers.
 
Docksidemarineservices said:
It is probably the fuel pump actuation rod getting stuck. After the engine is warmed and the oil flows this will stop.

2nd, if the garden hose can keep up with the raw water pump, it might be time to change the impellers.
Click to expand...

At the dock, my garden hose can keep the strainer full at 900rpm. At 1000 it drys/sucks air. This can give me a bit of a early read on the condition of the pumps and elbows.
 
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