A buddy of mine with his Hunter 40 and I with my Hunter 30 had the same problem this season with rock weed being sucked into our freshwater intake and clogging up the waterline aft of the straining basket.
Has anyone else had this problem and if so how have you corrected it. Is there a OEM part ( intake filter available?
If your raw water intake still has an outside "screen" I would remove it. This will avid having it clog with weed and the need to dive to clear it. If there are tight turns or restrictions in the hose and fitting path leading to your raw water strainer, can you relocate the strainer and/or reroute the hose to straighten and shorten the path?
From your description it is not clear to me if your boat actually has a strainer. I hope that it does; any weed that gets further in can clog up the heat exchanger.
(For example our '88 model boat did not come with a factory strainer so I installed a Groco raw water strainer soon after purchase. I clean it out a couple of times a season.)
Please post more details when you are able.
Regards,
Loren
