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FNG
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6 Posts
Discussion Starter #1
Hi Bob,
I bought an old sonic 30 with modified 454's with crossovers instead of circulating pumps. Even at an idle, I noticed periodic low water pressure on first one and then the other motor. I found that both mercruiser raw water pumps were leaking through the weep holes. I had new seal kits installed in the pump heads, And I have new impellers for them when I reinstall. Do you think I've solved the problem? The boat has low water pickups on either side of the keel, and after market thermo housings, with 150 thermos installed. Any advice will be greatly appreciated.
 

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Hi Bob,
I bought an old sonic 30 with modified 454's with crossovers instead of circulating pumps. Even at an idle, I noticed periodic low water pressure on first one and then the other motor. I found that both mercruiser raw water pumps were leaking through the weep holes. I had new seal kits installed in the pump heads, And I have new impellers for them when I reinstall. Do you think I've solved the problem? The boat has low water pickups on either side of the keel, and after market thermo housings, with 150 thermos installed. Any advice will be greatly appreciated.
Well, low water pressure at idle is not really an issue. If mine dips in idle much, it will just start to trip the sensor. Not alot of pressure or flow is needed at idle, right?

Yes, the drips from the pump(s) need to be fixed - but were both engines overheating at all before the pump rebuild(s)?
 

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FNG
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6 Posts
Discussion Starter #3
Yeah, a mixture of water, and steam. I guess what I realy want to know is are the stock mercruiser pumps being worked to hard without the aid of the circulating pumps?
 

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Yeah, a mixture of water, and steam. I guess what I realy want to know is are the stock mercruiser pumps being worked to hard without the aid of the circulating pumps?
No, they flow well more than they appear. When I have mine on the earmuffs (garden-hose adapter), I turn it on 1/4 - run to the boat and start it - run back and turn spiggot on full blast. When the boat is running, there is NO WATER DRIPPING from the earmuffs anymore. When the boat is shut off, the water sprays everywhere.

So, the stock sea pumps will take every bit of a 3/4" garden-hose feed.

If you have exhaust running out of the tips (boat running).......there WILL be some steam. There'd better be!

What I really wanna know is - - is the temperature gauge reading hot on both motors during idle??
 

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FNG
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6 Posts
Discussion Starter #5
The temp only climbs when the water pressure drops then the steam starts. I don't use earmuffs, there are pickups on either side of the keel that I use an addaptor to run one motor at a time.
 
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