jerrym

The Collierville Ski Club will once again host Seth Stisher for a ski clinic on Saturday and Sunday June 4-5. We still have a few openings in the schedule, and a beautful site with a new '22 Nautique 200, so come join us if interested. PM me for additional details and registration.

Sorry for the delay in following up. It turns out that the internal water pump was failing. Replaced the water pump and voila! I had never seen this failure in a boat and did not look closely enough at the internal pump. I’ve seen plenty of water pump failures in car engines but did not have the clue of losing coolant over time. A simple look at the back of the pump with a mirror would have been the smart move. I also did not consider the pressure that the second pump provides which is what is needed to get proper flow past the small thermostat opening. The lesson learned is that boat engines have two pumps that are in series and have different functions. Thanks to all for the suggestions on this journey.

The testing was done with a high performance crate engine with no knock sensors. The engine is in a separate room so they could not hear any knocking. They purposely avoided reducing the timing to the point of knocking to avoid engine damage. They noted that the testing was done under optimal air flow and cooling conditions and not necessarily what an engine will see in a vehicle.

@Jody_Seal we scanned the external temp with an ir sensor and confirmed the temp gauge. We had no prior temp issues. We check the impeller every 50 hrs and change it at 50 or 100. We have seen what impeller debris will do in a previous boat and learned that lesson. We use pcm parts. We have a heater. Why do you ask?? @buechsr we just received a new tstat and find that it is a 160 deg unit. We have confirmed that all of the tstats will open around 162 via the boil test. @jpwhit sorry if I wasn’t clear but the 30 gpm is at 3000 rpm with the intake connected and the boat in the water. If it was sucking air, wouldn’t that displace water and adversely affect the flow rate? We see no sign of air bubbles in the output of either pump.

@dw we have done the boil test and they all open at the same temp. We will repeat the test with a precision thermometer. The temp rating is not on the tstat. We can see by the engine temp that they open when installed. @Drago -two reasons. One we want to know the cause of the temp issue. Two -apparently the epa has regulated the operating temp for vehicles to maximize fuel burn so you can’t just grab a 160 deg tstat at the autozone any longer. @jpwhit the flow rate of 30 gpm at the outlet of both pumps suggests that both pumps are operating at design. We haven’t found an air leak or any indication of one. 30 gpm should be more than enough to cool a v8. Any thoughts on how to eliminate the incoming as an issue? Kinda feel like we’re chasing ghosts. We’ll check the lake pH this evening.

Thanks for the comments. This is beyond frustrating. @jpwhit We ran a single piece of hose from the pump inlet over the transom into the lake and ran at idle. There was no change in the flow rate and good suction at the end of the hose. @DW The flow tests were run at 3000 rpm. The 10 gpm per 1000 rpm reference is reassuring. Thanks for that data point. The boat only throws codes after multiple passes at 34 mph. Temp gauge is hitting 200 when this happens. The engine will then cool down into the 180s at idle. Starting cold it will also get into the 180s just at idle. The sensors are measuring the engine temp correctly and correlate with an ir sensor as well as the touch test. We have removed the tstat and the boat runs at full power but in the 130-150 range. We plan to run for a few days and then install another new tstat. The intent is to get solid flow through the system and flush it out. In the meantime we will check the pH of the lake. Our water level is very low and could possibly be alkaline. We’re not excited about running acidic solution through the engine but..... Thanks again ballers!

We pulled the hose from the raw water pump outlet at the thermostat housing and measured 30 gpm. Open to atmosphere. We then pulled the outlet hose from the circulating pump and measured 30 gpm there as well. Seems like this should be plenty of flow so we are moving downstream. Apparently there can be calcium buildup in the exhaust manifolds. We do not have hard water but we do use gypsum for water clarity. No sign of calcium buildup so far but I’m sure we pull in some silt since our lake level is pretty low. Still open for suggestions....

Thanks for the responses - much appreciated! @scoke - we swapped thermostats thinking that perhaps some debris had gotten into the thermostat and damaged it. We've seen this happen in the past when the impeller wasn't properly changed out. @MarkTimm - we'll check to see if we have a pressure relief. @MattP - we have a freshwater system so no coolant. You have me wondering if we have an air pocket in the system?? Others - To check the inlet side of the pump, we bypassed it with a single hose over the transom into the lake and got good suction on the pump but the same overheating issue. This does not preclude a leak on the inlet if the issue is an air pocket in the system. We'll proceed to run down any air bleeds or air pockets, and the source of air..... thank you!!

We have a 2019 Nautique 200 with the 6.0 liter engine and are getting engine cooling temp codes DTC 116, 1415 and 1416. My wide thinks it humorous that we can't fix this problem considering the hours we have spent on it so far: We have replaced the impeller and pump, reverse flushed the strainer, trans cooler and oil cooler, and tested and replaced the thermostat. The engine temp runs up to 200+ during a pass but cools at the end of the lake, so we know the thermostat is opening. The boat runs cold when no thermostat is in place but will not produce adequate power in this mode. The engine maintains temp when running city water into the inlet (essentially forcing more water through the engine). Has anyone seen a similar problem?

Currently enroute from CLE to MEM. Checked the ski in my snow ski bag as a second "special" bag for no additional charge. I've done this in the past in the same manner.

The Camaro suits have a lining behind the zipper that often gets caught in the zipper. Reverse the zipper a bit and pull the lining upward at the neck and the zipper will close freely. And please be careful doing solo projects in cold water.

@brettmainer thanks for the input. I was hoping I was missing something.

Our dripless seal is dripping....excessively. Can these units be adjusted? We have a 2019 SN 200 with 400 hrs on it.

@LeonL - that's a great idea...thanks! That brings back memories of pounding the dock posts into the lake bottom. @skierjp - Thanks for the info...they look to be the experts we need.

@JJSKI Great to hear you solved it. There's nothing like carving a ski through the turn....