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Converting Mercruiser 4.3 liter to Closed Cooling System

2K views 9 replies 5 participants last post by  Stray Current  
#1 ·
Does anyone have experience with converting their 4.3 liter Mercruiser engines to a 'closed cooling system' (like a kit from Performance Product Technologies)? The 280 Sundancer we purchased a few months ago has two of these engines, and I'm concerned about their long-term viability using salt water to cool them.

If so, I'm very interested in how the conversion went ... what were the benefits for doing it ... roughly what did it cost to do it ... and if you had it to do all over, would you do it again?

Thanks!
 
#7 ·
You might consider adding a fresh water flush to your system. IE like this https://easyflowflushing.com/product/easy-flow-flushing-kit/ I'm not advocating their system but just the idea. I added something to my old 310 and found that as long as I was religious about flushing after use it seemed to eliminate crude / rust coming from the discharges when I started up the motors.
 
#8 ·
Thanks - I've looked into that a bit. What I've learned so far is that the Alpha 1 series outdrives that we have are not compatible with these type of quick connect flush systems, because the pump system impellers are in the outdrives themselves. Which means I've got to flush the motors from outside the boat (bad luck for me). At least that's what I've been told so far.
 
#10 ·
I’m another vote for don’t bother, I’d just flush after use. The salt has already gotten into everything and they’re already 22 years old. I’d definitely go FWC on the repower though
 
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