Originally Posted by psneeld
I think outboards and some I/O models have seawater pressure guages installed..may work..they aren't too much money and are pretty easy to install.
Hmm. Now that might just work, thanks! My last boat actually had a water pressure display on the engine computer monitor, but I never really know what it was telling me.
Originally Posted by bligh
Why not just change the impeller every 200 hours or annially like your manual says and don't worry about it?
A good point to include here for the record. But I've actually changed them FOUR times in the past two seasons, so that's not really the answer. Only once did it make any difference. The overpriced aftermarket "run dry" high-tech impeller I bought, thinking I wouldn't have to worry about it all season, turned out to be a dud and actually CAUSED a near-overheat once.
As with the other times (not related to impeller failure), I detected the problem by climbing down on the swim platform to check the coolant flow visually. Very effective but not very convenient.