Kaboom!

Tough day on the water.  Sorry for that.  As far as what to do?  Let it rest for a few days then get to fixing the broken stuff.  Not easy or cheap but in the end its gotta get done.

Bummer, the wind did kick up strong yesterday, glad you got help to get off the water.

Just an idea since one head is coming off, not sure what head the 90 engine used but the GT40 heads did get better as the years went on, you might find a pair of the better heads and have two rebuilt heads.   Hate to share this but after an overheat many times the head gasket fails a short time later.  In overheat the cylinder head grows the fastest since that is where the combustion starts, when the head is not cooled it grows and actually crushes the head gasket.   On tear down you can measure the gasket thickness and see exactly where the crush took place, normally that is near the exhaust ports in the head.   So you might replace your one head and get it running perfect only to have the second head gasket fail a short time later.   It is apart now, not much more work to fix both heads and have two new head gaskets.   Maybe the newer heads can kick in an extra 30 HP as part of the repair.  Again, not sure what year the heads changed but power did go up with them.   I know the 1995 is rated 310 HP and most of that is better heads.  Fuel injection adds better drive experience but a good carburetor can normally come within 10 HP of a FI engine all else being equal.  Was the 1990 engine still 250 HP?

Thermostat stuck closed or blocked?

Aha! 

So  today we tried to see if it will fire. Reinstalled distributor, cranked it over, no spark, I had a new coil, installed, spark from coil, none to plugs, spark when opening points, spark to dist cap. The heat killed the coil and wires, so getter the right wires, cap and rotor. tomorrow.

cbr1000dude wrote: 63 Skier wrote: So if you are a 79 year old with a CBR1000 and a '90 Ski Nautique, you're who I want to be when I grow up! Glad you found the problem, now a matter of running it with fingers crossed.  Hoping you plan to run it in your driveway with the timmy-tee method, not on the water, so you can see cooling water flow out the pipe. Yeah, I'm old, but not ready to give up yet. I think playing with all my toys keeps me going. The CBR1000 is long gone, I've had a few bikes since then, but sold the last one 3 years ago. My 370Z convertible with the top down is my DD now. Don't have to put my foot down at lights anymore.

We have seen the cooling ports blocked by pieces from a failed impeller many times, I can’t say I have ever heard of them being blocked by sand.   In the old jet boat days we did see blocks get so much sand in the cooling jackets that they would start to run hot but that was running in shallow rivers with lots of sand to suck up and jet boats had 400 HP pumps sucking the water in not a simple Raw Water Pump.

It's alive!

Thanks for the good wishes!

Nice! Glad you and the wife are making progress.   BTW I skied a summer once back in 1984 or so with our 1978 Nautique, it was a V7 almost all summer with a burned valve in one cylinder.  We were able to Ski and barefoot behind that V7 so it still had pretty good power.  The valve burned at 900 hours on the clock.  With new heads that engine was still a champ at 1500 hours when we sold it.

So yesterday I got it completely finished, but not without removing the intake manifold to install new gaskets on both sides and lots of gasket maker goop on all the sealing surfaces.. I waited 24 hours before starting it to let it cure. Man is that thing heavy! I used 4 six inch pieces of threaded rod as guides to make sure it landed in the right place. Same way I did the head. Drop it in place, install most of the bolts, then remove the threaded rod and replace with the original bolts.