Logo

Crusader 454: Air in raw water intake strainer (Starboard engine)

Lawlila

New member
[h=2][/h]
I have a new to me 84' Trojan 11meter Express with Crusader 454s. Just over 500hrs ea.. Closed cooling. After bringing her to her new home, I noticed the starboard raw water intake strainer was only half full of water and half full of air. The port side was still full of water. No overheating occurred. I was told the impellers were newer. The setup goes: Thru hull seacock, hose, valve, hose, strainer, hose, pump. I don't notice any leaks, but it appears that both the port and starboard strainers have been sealed with a black silicone/rubber substance, and I'm definitely not going to be opening them. Perhaps they were leaking at some point. Any ideas as to why there would be air in the strainer? While running the engine at the marina, I can clearly see water pumping and it seems to be maintaining/keeping up the half full scenario. The strainer is an older low profile brass with clear top and wingnut on top of that. Hoses look newer and the strainer only has minor debris. Thanks in advance!​
 
U have an air leak. Why is there a valve and a seacock?

Thanks for responding, really appreciate your time. I tightened all the hose clamps but haven't had time to replace the impeller yet. Where might you think the air leak is? Raw water pump/impeller? I believe someone put an extra valve in because the seacock is a pain to access, and the low profile strainer is at or just below the water line. So perhaps for ease of cleaning the strainer and shutting off the water intake.
 
Thanks for responding, really appreciate your time. I tightened all the hose clamps but haven't had time to replace the impeller yet. Where might you think the air leak is? Raw water pump/impeller? I believe someone put an extra valve in because the seacock is a pain to access, and the low profile strainer is at or just below the water line. So perhaps for ease of cleaning the strainer and shutting off the water intake.

If you are getting air into the strainer while running, it must come from below (upstream) the strainer, towards the thru hull. Likely one of the valves has a small air leak. Could be the seal on the strainer itself.
 
both the port and starboard strainers have been sealed with a black silicone/rubber substan
To me that is a hint that there was leakage on either port or starboard strainer and the previous owner decided to seal both to make sure that that neither one would leak...again
I would close the sea cock on the offender and clean the silicone away and check the strainer for leakage and then cap it the way it was supposed to be capped. Open the sea cock and try running the engine.
 
I had an air leak in the lid of my strainer once. I couldn't get it to pump water. I pulled lid off, made a new cork gasket with scissors and sharp knife, replaced lid and away I went. Don't be afraid to open up the strainers. That may be the problem.
 
I had an air leak in the lid of my strainer once. I couldn't get it to pump water. I pulled lid off, made a new cork gasket with scissors and sharp knife, replaced lid and away I went. Don't be afraid to open up the strainers. That may be the problem.


Right on! Think I'll be replacing the strainers as well. Like I mentioned in the original post, I think the previous owner may have had issues with them before, hence the added sealant. Thanks for responding, appreciate your time!
 
Not sure what type of strainers you have but on my twin 454's I have Sherwood plastic strainers with ss mesh internal screens. Mine are 1 1/4" supplies. They aren't fancy bronze strainers, but they seem to be doing the job and can be purchased for about $50 per side, excluding fittings. The clear housings spin off like an oil filter would to clean them out.
 
So I finally had time to work on the boat. I started by replacing the impeller, which was in good condition, then ran the motor and there was still air in the strainer. Then I started opening the strainer lid and all the air escaped. I simply tightened the lid back down securely and started the motor back up and to my surprise everything was fixed. Guess the strainers just need new gaskets! Thanks again to everyone for their time and responses! Much appreciated!!!
 
Back
Top