Water circulation problem

Discussion in 'Sterndrives' started by Sonic, Jun 28, 2009.

  1. Sonic
    Joined: Jun 2009
    Posts: 2
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Plano, TX

    Sonic New Member

    Hello there,

    I'm new to this forum, and also new to boating. I just picked up my first boat a few days ago. Its a 74 searay srv190 with a mercruiser 302 and what I believe is an Alpha one outdrive.

    When I purchased the boat the previous owner told me that it was running warm, and probably needed a new impeller. I purchased a kit the next day and installed it on saturday. Took it for a test run to the lake today and it started to run hotter and hotter. I shut it off and let her cool down for a while and then loaded it up and took her back home. I pulled the thermostat housing only to find that it needs replacing due to corrosion, but the thermostat isn't stuck. I dropped it in boiling water and it opened right up.

    I dunked the outdrive into a large tub of water and started the engine with the thermostat upper housing removed. No water pumped through at all. I poured water into the lower housing and it did flow out.

    Does anyone know what could be causing this problem? I'm thinking about handing it over to a marine mechanic and just letting him work on it, since I'm pretty green when it comes to outboard drives and marine engines. Before I do that though I'd love to hear some ideas from ya'll about what could cause this and if it might be an easy fix I'd just do it myself.


  2. fasteddy106
    Joined: Apr 2009
    Posts: 72
    Likes: 17, Points: 0, Legacy Rep: 171
    Location: connecticut

    fasteddy106 Junior Member

    Do you have a service manual? If not, you should get one. Check the water tube in the upper housing for blockage and move your way to the engine. Of course 1st check that your hoses are not blocked with sea goo etc. Squeeze the hoses and if you feel a crackle, replace them. Of course you may have messed up the impeller installation. I always do the entire pump assembly to avoid this. Good Luck. You can get parts for the upper and lower here .............

  3. Sonic
    Joined: Jun 2009
    Posts: 2
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Plano, TX

    Sonic New Member

    I do have a manual for it

    Well I did hook a garden hose to the upper and check it for blockage and it was flowing water just fine.

    Then I check the grates on the water pick up point on the lower. Nothing behind the grates.

    I just finally gave up and took it to a boat mechanic.

    Thanks for the help Fast Eddy. :)
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