1981 SRV 245 Sundancer running hot

Discussion in 'Classic Sea Rays' started by Bill Nelson, Oct 21, 2019.

  1. Loyd Dinneen

    Loyd Dinneen Active Member

    384
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    It looks like this ole girl has been moored for a long time without being looked after. Yep for sure replace the riser hose first and don't forget to use some WD40 or penetrant for all the bolts, prevents the broken bolt issue you have now. Replacing the hose will give you the chance to inspect the riser which I would think is in sorry shape also based upon the looks of everything else. Turning the lower shaft by hand will be hard as theres not much leverage and also because you have a new impeller on a dry housing will have some resistance. I found that removing the complete outdrive makes it easier to work on and to reinstall the lower portion. You just have to make a rack for it and another body to help you lift it. Also you need to inspect the bellows, gears, and gimbel bearing as I am sure it has been awhile since that was done. I live near Lake Mead and this is what outdrives look like after they have been in the water for a long time or moored in saltwater. And last if you have not done this before study up on what to do before you tackle it will save you alot of time and broken parts.
     
  2. Bill Nelson

    Bill Nelson Member

    36
    Oct 21, 2019
    New River, AZ
    1981 Sea Ray Sundancer
    5.7 L Mercruiser

    Hi Loyd,

    Yep she's been around, but thankfully the motor has been well cared for. Excellent compression on all 8, oil is like honey and no metal. The outdrive has seen better days, but I have it all off now: new upper, seals, new water pump, shift cable, cable bellows, gaskets and it is going back on this week. Next thing is an ops check to make sure the water circulating system is working properly.
     
    Last edited: Dec 2, 2019 at 10:52 AM
  3. Loyd Dinneen

    Loyd Dinneen Active Member

    384
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    If this is a closed cooling system then consider changing the coolant and giving it a good flushing. Also look at the heatexchangers for any cloggs by taking the end plate off. When running the engine touch the top of the riser with your hand you should be able to hold it there without burning you, if you can't you will need to take off the risers and inspect and clean them and the passages. I had the same problem and I took off the exchangers and flushed them with meratic acid, flushed the cooling system with automotive flush and added new 50/50 antifrezze. I also replaced both risers,cleaned the passages,and put in new shutters that were missing. While you have the outdrive off look inside the exhaust area and see if there is any debris that is obstructing the exhaust. When you replaced the waterpump if there is any fins missing go for a hunt for them in the hoses and other passages. All of these things can cause a over heating problem. I did all this and it fixed my over heating.
     
  4. Bill Nelson

    Bill Nelson Member

    36
    Oct 21, 2019
    New River, AZ
    1981 Sea Ray Sundancer
    5.7 L Mercruiser
    It's got a what the manual calls "Standard Cooling" - no heat exchangers. Removed the outdrives and cleaned all of the debris (there was a boatload).I replaced both of the Exhaust Elbows. Are those what you're calling the risers?

    I am fairly sure the root cause of the problem was the water pump in the lower outdrive. It was reassembled without the bottom O-ring that prevents water pressure from venting into the drive.
     
  5. Loyd Dinneen

    Loyd Dinneen Active Member

    384
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    Yes those are risers did you notice if the shutter was still in there? That part is very important as it prevents water from entering your exhaust when back down on the throttle and going into your engine causing hydrolock and engine failure. They are located just past your risers in the the exhaust. A screwed up waterpump and dirty outdrive will sure cause a overheating issue I would think. You should now be able check the risers while the engine is running and should be able to keep your hand on them without getting burn't.
     
  6. Bill Nelson

    Bill Nelson Member

    36
    Oct 21, 2019
    New River, AZ
    1981 Sea Ray Sundancer
    5.7 L Mercruiser
    I don't think the shutters are there on my boat. They are installed between lower exhaust elbow and the exhaust separator:
    flapper.jpg
     

Share This Page

Show Sidebar