Went over a large wave yesterday and directly after that I noticed the water
temp was over 200. Out of habit I scan this and the other essential gauges
regularly when running. Up to that point the temp was the normal 160-170. I
went to idle and then turned the engine off since this happened once before
where I probably picked up a plastic bag wrapped around the water intake on
the i/o. I raised the drive and felt around the intake holes searching for
blockages. None found at the holes, but a healthy crop of barnacles were
populating the surrounding areas of the drive. Started it up again and
revved it a couple of times and the temp subsided to normal. Then a few
minutes later the temp was up there again. I stopped. Turned off the engine.
Restarted. And again, back to normal. This happened once or twice more
during my time out but on these later occasions all I did was put the drive
in neutral, rev the engine a couple of times, put it back in drive and the
temp went back to normal saving me from having to get back up to plane from
a dead stop.

The question is, did I cause come damage, say, to the impellor from the
impact on that large wave (this was a wake from a large ship that had passed
about a 1/4 mile away in an otherwise flat and calm sea) or was it just
coincidental that I may have picked up something that would cause random
blocking/malfunctioning of the cooling system (would have to be pretty small
to fit in the intake holes)?

Thanks for your help.

-Mike
1987 Sea Ray Sundancer 250
Repowered with a rebuild last year with 160 new hours on it.