Locating a Blocked Cooling Passage

[WREKS]

@buckbuck Thanks for the additional readings.

 

[IN2H2O]

It's been a few days poking around, here is where I'm at. I fiddled around with some wires and fuses behind the helm and got the no wake working along with all 3 lights on the tach. So I'm hoping the temp probes are functioning correctly to help protect a overheat situation.

I ran the boat on the hose but this time I took vice grips and crimped off the Y fitting #2 (pump intake) so all water had to pass though the motor somehow. I still did not get any water to the overboard pissers ran on the hose for about 2 minutes or so. Also tried increasing RPM to no wake mode without much effect. Pulled the #10 fitting and was barely getting water though it. I blocked it off with my finger in hope to fill the rubber water jacket around the exhaust and it did slightly and I got my first drop or 2 out the pisser. hooray!

Poking around more I found the #12 hose after the T-stat was kinked which now has me worried because if that was kinked shouldn't I see ALOT of water coming from the rear pisser? I'm really confused why I'm not at this point





Next Steps:

• I ordered a YDS, should arrive Tuesday. I also have a Fluke IR thermometer from work. My question here is do I need to run it on the lake or is on the hose ok? What RPM range for how long to take a temp reading hose vs lake?
• This is a salt boat and was curious best way to clean internal passages of any buildup? Can I let a solution sit in the motor for a certain amount of time before flushing it out?
• Compression tester arrived so going to check compression but motor is running 10K and 45-47MPH so I think I'm ok but I'm very nervous with all these other findings
• Any other recommendations?

Thanks in advance and for all the tips thus far. This community rocks

 

[WREKS]

Might be thermostat. Try removing thermostat from system and see if you get flow out of 19 and 15.

 

[IN2H2O]

Might be thermostat. Try removing thermostat from system and see if you get flow out of 19 and 15.

Not sure if this helps but visual of water flowing into T-stat at full hose power. Does this seem like normal pressure. Alot of water was still exiting the exhaust

 

[Scottintexas]

Look in the faq section for cranky gypsy's closed loop flush


,

 

[WREKS]

Seems a little weak. Is the thermostat in specification?

 

[IN2H2O]

Seems a little weak. Is the thermostat in specification?

I believe it's in spec. Manual shows closed at 50C which mine is and 4.3mm at 60C and I'm 3mm at 60C but might be measurement error as they don't show exactly how to measure.






However now I have a new issue. There is a hole in the thermostat's metal disc, does it matter if that hole is clocked to a certain degree when i reinstall it?

 

[IN2H2O]

Also to my surprise the buildup did not seem to heavy in the housing or thermostat itself. Bottom half showed deposits and the top was virtually clean.

 

[WREKS]

What about comparing the water flow into the thermostat of the other engine?

 

[IN2H2O]

What about comparing the water flow into the thermostat of the other engine?

Took the other side of the line off the 'good flowing' motor as the thermostat clamp was not budging. Not 100% apples to apples but kinda hard to tell the difference in my opinion. I'm confused why if the bad flowing motor has a working thermostat and a nearly kinked hose going down to the pump's #15 fitting that the overboard pisser is not flowing. I have confirmed that line is not blocked

 

[WREKS]

As long as you are this far, maybe checking the volume flow would be helpful. For example count to 10 and see how much collects from each hose.

 

[IN2H2O]

Let's call them similar. 13oz in 5 seconds each. I'm sure at larger volumes the differences may show. Only thing I can think is the t-state is not opening bc it's not getting warm enough. But why would that be?

 

[WREKS]

Is that at idle or No-Wake mode? Idle will not stream any water from the pilot. No-Wake mode will, if the cooling system is not blocked. I would try the same volume flow experiment, except in No-Wake mode.

 

[IN2H2O]

I'm not currently testing on the lake so pump pressure is not in play here.

 

[WREKS]

Sorry, previous post assumed thermostat is in the loop.

 

[IN2H2O]

Flow rates are just before thermostat

 

[WREKS]

If the hoses are unkinked and connected, and the three warning lights blink in No-Wake mode, I would try to run on the hose in No-Wake mode for 5 minutes and see what happens.

 

[WREKS]

Engine should go to idle if any problem arises.

 

[IN2H2O]

I've ran the boat at 10k rpm and 45-47mph and it didn't trip over temp but the run was only for about a minute before I noticed it wasn't pissing so I idled back to the ramp. What will no wake tell me that that test didn't?

 

[WREKS]

That is a great question. I think there are two dynamics in play. On the MR-1s there is a low speed, and a high speed, consequently two sets of pilot water hoses. In the low speed water gets circulated through the cylinder water jackets and exits out by the thermostat. In the high speed water hits the manifolds and continues out to join the exhaust. There is some mixing that goes on. Most of the overheating that I have encountered takes place at lower rpms.