Excalibur Cooling Issues

[glassywaters]

I have a new to me 2002 Super Sport Nautique with the Excalibur 330 engine with the side mounted raw water pump (early model, but not a part of the recall). I was having some cooling issues when I bought it and went through the whole cooling system, replaced the t-stat gauge, replaced the impeller (used the gasket and o-ring provided), tightened all hoses, lubed the strainer gasket, lowered the strainer (as recommended on this forum), replaced thermostat, and even replaced riser gaskets. Water was flowing good on the hose at the house and no air leaks and temperature was between 160 and 180 (backed down to 160-170 with RPMs). I brought it to the ramp for a water test, running on its own and engine went straight to an overheat with no water flowing. I spent about 20 minutes checking hoses and it wasn't getting flow out of the raw water pump. I ended pulling the intake hose to the raw water pump and syphoning water into the system. After that, the boat ran great for two hours with a surf session and wakeboard session in between. So now for my questions:

1. What do I do about the pump losing prime? Certainly, don't want to be dealing with this every time I launch. I trailer the boat 100% of the time.

2. Temperature ranges from 160 to 180 (coming off plane). Seems to be operating in the 170 to 180 range, but it has the 160 t-stat. The t-stat really seems to bounce around a lot and hits 180 before temperature backs down to the 160-170 range. Is this normal?

3. I was thinking up upgrading the RWP to the crank driven style. What do you think?

Also, loving the new boat. I have a WakeMakers order arriving Tuesday! Thanks for the help.

[Skidave]

Something is wrong. You may have an air leak before your raw water pump. Have the exact same motor. Your temps should not be above 160 unless you're cruising at high RPMs.

Check strainer gaskets, hose clamps, hoses and your hose connection setup (if you are not using a fake-a-lake).

Sent from my SM-J320V using Tapatalk

[charlesml3]

Agreed. There's no such thing as these pumps "losing prime" because they don't need to be primed. Any time you pull the boat out of the water, any water "south" of the pump drains out. When you drop the boat in and start it, the pump starts drawing. It'll draw air until the water gets to it.

-Charles

[glassywaters]

Thanks for the replies. I am using a barb'd tee with a hose bib or 'Timmy T' to run the engine at home. On my boat there is a shut off valve for the water intake. I've used the two to pressurize the cooling system to check for leaks, before I started it was leaking everywhere, but it's now dry as a bone. I know this is the first thing to check, so I've triple checked for air leaks. I do believe there is a problem, but not sure what to check next. Also, if you are not familiar with this model Excalibur there is a side mounted raw water pump, unique to 2002 and some 2003 engines before the crank drive pump and later serpentine pump was introduced. Some of these pumps have a known recall for losing prime, see below link.

http://www.planetnautique.com/Correc...SUP2003-07.pdf

I'm wondering if a previous overheat or destroyed impeller is blocking the cooling system at some point. I've pretty much rebuilt the whole cooling loop external of the engine and removed many pieces of impeller. The only 'temperature' indicator I can see, beyond the running warm is that my starboard riser is running a good bit hotter than my port. I can keep my hand on the port at all times, but the starboard is getting hot to the point where I can't hold my hand there without discomfort. I just went out and ran it again on the hose and I'm right at 170 and holding at 180 and back down to 170, but not any hotter.

[obd666]

yes, there was definitely an issue with some of those old pumps not priming. Does yours fall into the SN# range specified in the recall? I had one years ago that the serial was just outside of the specified range in the recall, and it stopped priming and/or holding prime just like those did. The replacement pump has never had an issue.

is your pump just a flat surface under the back plate, or does it have a groove with a rubber o-ring in it? that was the difference in my failed pump vs the new one. Also, when you are running it at home is it under pressure or is it pulling the water up and through by itself? i typically connect a clear piece of hose up on the high side of the transmission cooler and run it into a big cooler of water. then I can observe how well the pump is pulling the water in under its own strength.

[Infinity]

A replacement pump should not be that expensive, sounds like that is probably what you need to do since under pressure (from hose)....its good but without pressure it does not want to prime. My guess is that its sucking air at the impeller cover, you could maybe try to add liquid gasket around the lid to see if that seals the leak so you get another summer out of it before replacing....let it cure before you test if you do go that route.

[dkimball]

I have a 2003 Excal with the belt driven pump and had an issue with leaking around the impeller cover this year after I changed it out. The problem was the cheap paper gasket that was included with the impeller. I went to an auto parts store and bought a sheet of water pump/thermostat paper gasket and cut my own. This was a lot thicker than the one that came with the impeller and sealed it up no problem.

[salbertson]

glassywaters did you ever figure out why your engine was running a little warm? I'm having the exact same issue with a 2003, even the same riser is warmer than the other.