Seawater Pump and waterflow

[ronzdonz]

I own a 1970 18 2+3 with the original H/M 351W and Volvo outdrive. I have a question about the Jabsco seawater pump which was just rebuilt. I only seem to be getting water flow through the exhaust once the thermostat opens. My engine runs at a steady 160 degrees so overheating is not a problem. Should I be getting a continuous flow through the exhaust or just when the thermostat dumps? It seems that the only way for water to flow into the risers is from the "T" that comes off of the thermostat. I can't figure out if I have a problem or not. Doesn't someone have a CD with the manual for these classics somewhere. It would be nice to get a copy.

[GeneD]

Lots of times when I flush out my motor or when I'm getting ready to go for a ride, the motor will take a few seconds to fill up with water before it comes out the exhaust pipes.
And I KNOW everyone checks out their boat before going out right? So back me up.

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GeneD
007
Melbourne, Florida

[Jamesbon]

I'm not an expert here, but I did learn quite a bit when converting my raw water cooled system to a fresh water system. I drilled a small (1/8" or so) hole in the thermostat to act as a water by-pass when the engine is cold and the water isn't flowing due to the thermostat still being closed. I figured this might keep the manifolds from heating up. In your case, would think you're okay, as long as your exhaust risers/manifolds aren't starting to cook before the water starts flowing. Just my thoughts.

And yes, Gene, I don't move my boat before I check for "tailpipe" waterflow. I cooked the rubber exhaust tubing once, years ago, I left the freshwater intake hose cap off - the H2O pump sucked air instead of water. (oops!!) Luckily I was just a few hundred yards away from home.

[GeneD]

Well actually, I was trying to get the point across to some people that going boating doesn't always mean hooking up the trailer to the car and driving off to the ramp without first going through your pre-flight checklist and actually flipping switches, starting the engine, actuating the trim, making sure the cooler is full of iced beverages, ect.
How many people have you seen at the ramp repairing something that should have been taken care of in the driveway?
Yes, I've been guilty of a dead battery at the ramp, and once my starter refused to turn over, but my pre-flight wasn't prudent due to being away from home (my shop) immediately prior to launch.


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GeneD
007
Melbourne, Florida

[This message has been edited by GeneD (edited 05-27-2000).]

[ronzdonz]

Thanks guys for all of the info. I agree that a good checklist makes it a lot easier than rowing or being towed in. Be safe this weekend. The weather here in southern Maryland looks like its gonna suck. Oh well...I'm still gonna launch.