Frank 157 Posted September 3, 2018 Share Posted September 3, 2018 Morning all, I have a seawater cooled Vovlo MD7B, (3000 SERIES ?) long story but I had to take the thermostat out of the watercooled exhaust manifold. I cant put a new one in due to corrosion damage but the manifold is fine otherwise and they are eye-wateringly expensive. The motor did not seem to mind and still came up to temp but perhaps a bit slower, no biggie. However I recently replaced the impeller and now the flow is such that it runs way too cool. Clearly the old impeller delivered a degraded flow that was nevertheless about right. I have a digital temp module with an alarm so i can monitor it accurately. I was wondering about putting a second valve in the inlet line as a partial restrictor and then experimenting to reduce the flow to get a good balance again, thoughts ? chrs Quote Link to post Share on other sites
Fish 0 Posted September 3, 2018 Share Posted September 3, 2018 You may stuff your raw water impellor if you restrict the inlet flow, more so if you run the engine with the water flow completely cut off. You could toy with a restrictor plate on the outlet where the thermostat was, i.e a plate with a hole in it. Monitor with your digital temp module, or better still a IR temp gun while you are determining the optimum hole size. If it gets too hot, just drill a bigger size in the plate. An open thermostat will restrict the flow more than no thermostat in the same space, so wont hurt to "replicate" the restriction of an open thermostat. I don't have enough knowledge to comment on running an engine cold for too long. I wouldn't think it would be good though. Excessive wear while things warm up, i.e. expand to take up slap / tolerances etc. Quote Link to post Share on other sites
Black Panther 1,566 Posted September 3, 2018 Share Posted September 3, 2018 Good to hear. My boat has an ld28 28. Quote Link to post Share on other sites
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