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JGTate

2003 Monsoon 335 Overheated only AFTER draining block

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JGTate

Yesterday we overheated after running 20 minutes up to the slalom course- boat was at 160 the whole ride then over temped and said 205 on the gauge as we slowed down.  Things have run well all year.   

The only difference is that I drained the engine per the indmar manual about 10 days ago when we had a cold snap, so there was lots of air in the system to start.    After overheating I tightened all connections, Checked the impeller which looks good, blew through the inlet back under the boat and the trans cooler and have water flowing well up to the junction block where the thermostat is.    I tightened all the hose connections and plan to remove the thermostat.  

A basic flow question- Is raw water supposed to go INTO the block at the circ pump and OUT at the top of the intake through the thermostat?   if so it seems like the water circulating pump on the engine isn't working as other posters have said.    When I felt the large U shaped hose that feeds the circ pump it seemed like it had little water in it.  However, was I supposed to prime the circ pump it somehow after getting air in the system?

i guess another way to put it is....would a stuck thermostat allow the engine to run 20 minutes before overheating by blocking the flow OUT?

it seems strange that a circulation pump would fail suddenly, especially only after I drained it....any help would be appreciated.  Thanks. 

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Woodski

@JGTate:  Answer to question is yes, from raw water pump to circulation pump inlet in to the block then out at the thermostat housing.  If you were running for 20 minutes and at speed things should have been operating correctly.  The system does like to be primed when emptied of water but usually that happens with extra throttle input.  Do you have a strainer and if yes, perhaps it ingested something causing a blockage.  A stuck tstat could allow the engine to idle for an extended period but not run under load.  There could be an air pocket right by the gauge sensor.  If you have an infrared thermometer, shoot the thermostat housing area to see if that matches the gauge.  The sudden issue you describe IMO indicates either a circulation pump failure, an impeller issue (which you indicate is not the problem) or some blockage.  Could be the tstat but seems very odd after running for a while.

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minnmarker
1 hour ago, JGTate said:

After overheating I tightened all connections, Checked the impeller which looks good, blew through the inlet back under the boat and the trans cooler and have water flowing well up to the junction block where the thermostat is.

Not sure what you're saying but you should not be able to blow water through the raw water pump. If you can there is something wrong there.

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Cazan
2 hours ago, minnmarker said:

Not sure what you're saying but you should not be able to blow water through the raw water pump. If you can there is something wrong there.

I think he’s saying he blew out the transcooler screen and the thru Hull water intake screen on the bottom of the boat to make sure they weren’t clogged. 

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justgary

The raw water impeller can spin on its hub and still look good.  How old is it? 

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JGTate

Not sure on the impeller age, bought the boat this summer.  It's a blue color which I haven't seen before.   I ran the boat today with no thermostat and it seemed to be ok, wouldn't warm up but then after 5 minutes or so the impeller plate got hot and the exhaust seemed like it was bubbling from the heat.       Not sure if there is some type of debris trapped from the strainer to the pump inlet, but will order a new impeller and thermostat and go from there.   

Does the impeller just pull off the shaft with pliers?  Assume it's keyed to it.  

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justgary

That's a Globe "Run Dry" impeller.  If the plate got got, it may be slipping. 

Yes, just grab it with pliers and pull it out.  It might walk out a little on its own if you remove the plate and bump the starter with the lanyard pulled. 

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JasonK

Blew through..... might not have gotten any junk to block the trans cooler "screen".

Running the boat higher than idle can force water to circulate, but once you slow down the low suction can cause any blockage to cover the trans "screen". And that would explain why the impeller cover was hot when you ran without a thermostat. Check your trans cooler screen for debris. The screen strains the flow to the circulation pump and engine.

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justgary
23 hours ago, minnmarker said:

Not sure what you're saying but you should not be able to blow water through the raw water pump. If you can there is something wrong there.

When I had a blue Globe "Run Dry" impeller I could always hear water bypassing the impeller when I hooked up the garden hose to the flush port.  Those things are definitely different from the regular black rubber ones.

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Woodski
13 hours ago, JGTate said:

Not sure on the impeller age, bought the boat this summer.  It's a blue color which I haven't seen before.   I ran the boat today with no thermostat and it seemed to be ok, wouldn't warm up but then after 5 minutes or so the impeller plate got hot and the exhaust seemed like it was bubbling from the heat.       Not sure if there is some type of debris trapped from the strainer to the pump inlet, but will order a new impeller and thermostat and go from there.   

Does the impeller just pull off the shaft with pliers?  Assume it's keyed to it.  

From this comment, you are indicating there is not enough water flow through the system as the exhaust got what appears to be warm assuming that is different from your 'good' operating condition.  The hot impeller plate indicates either the internal pump clearance is not correct or the raw water pump is not drawing enough water.  You might want to measure and compare old v new impeller to verify and check to see if the impeller hub is not disconnected from the impeller itself or the flat or key is in good shape.  You might just try a new impeller.  Also, check your thermostat on the stove, just drop in a pan and heat up the water to see if it opens at the correct temperature (use a meat thermometer to verify water temp).

Impeller should simply pull out of housing with either needle nose pliers or a paint can opener (better).

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UWSkier
1 hour ago, Woodski said:

From this comment, you are indicating there is not enough water flow through the system as the exhaust got what appears to be warm assuming that is different from your 'good' operating condition.  The hot impeller plate indicates either the internal pump clearance is not correct or the raw water pump is not drawing enough water.  You might want to measure and compare old v new impeller to verify and check to see if the impeller hub is not disconnected from the impeller itself or the flat or key is in good shape.  You might just try a new impeller.  Also, check your thermostat on the stove, just drop in a pan and heat up the water to see if it opens at the correct temperature (use a meat thermometer to verify water temp).

Impeller should simply pull out of housing with either needle nose pliers or a paint can opener (better).

Your experience with impellers is a bit different than mine.  They're a pain to remove.  I usually remove both hoses and the L bracket that holds the impeller housing, then rotate the entire assembly back and forth while applying a pulling force to the impeller with a pliers.  Seems I can never get the things out without doing that trick.

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oldjeep
28 minutes ago, UWSkier said:

Your experience with impellers is a bit different than mine.  They're a pain to remove.  I usually remove both hoses and the L bracket that holds the impeller housing, then rotate the entire assembly back and forth while applying a pulling force to the impeller with a pliers.  Seems I can never get the things out without doing that trick.

If you rotate the engine a little by hand first they come out a lot easier

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electricjohn

I spray WD-40 in the housing and on the splined shaft before and after removal of the impeller.  Once new impeller is in, I rinse with water then install the cover.

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UWSkier
34 minutes ago, electricjohn said:

I spray WD-40 in the housing and on the splined shaft before and after removal of the impeller.  Once new impeller is in, I rinse with water then install the cover.

The impeller kit I order comes with a little lube tube to put in the new one, but I've always found it way easier to put in the new one than take out the old one, lubricated or not.

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JGTate

Thanks everyone, this is great info.  Ironically the globe “run dry” seems to have started acting up after it ran dry for a few seconds after I drained the hoses to prevent freezing.  Will try the suggestions, pliers, and let you know.

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JGTate

Ok, so an update, I found multiple bits of a previous dead impeller and some leaves and weeds blocking the transmission impeller screen.  Got it all back together and had trouble getting the system to purge air out so I removed the hose at the trans cooler while running a few seconds and after all the air came out a glug of water quicky splashed on the alternator.  Immediately afterwards the boat wouldn’t start.  Dumb move on my part.  

1.  Does this engine normally need a purge or prime when completely dry?  And where should you do it?

2.  Did I majorly screw up by dousing the alternator for a second?  There are no error beeps or warnings and the temp sensor was not reading, which I assume is because there was not yet water in the engine, but maybe there is an overtemp safety?  The exhaust was already hot after 2 minutes of running with no water.  I thought you could run with a defective alternator but this is my first computer controlled boat.    

3.  Any ideas on What should I do next, assuming the no start continues?   I put it aside to dry out.

Thanks  

 

 

 

 

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ahopkinsVTX

The engine can need a prime after being completely drained. Normally a burst of throttle will do it. 

For the alternator, I'd remove it, let it dry then go get it tested. 

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oldjeep

Couple thoughts. 

1}Throw the globe in the garbage, some love them but they are notorious for not priming - although even a normal impeller may require a throttle bump with a dry system. 

2} start checking fuses and battery connections.  Wet alternator should not keep engine from firing.  When yiu tried to start it, did it crank but not fire?  If so i woukd check if you doused the distributor. 

 

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boardjnky4

Just let the alternator dry out for a while.

Swap out the impeller, regardless of what the testing is indicating.

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JGTate

Ok, so an update, I found multiple bits of a previous dead impeller and some leaves and weeds blocking the transmission impeller screen.  Got it all back together and had trouble getting the system to purge air out so I removed the hose at the trans cooler while running a few seconds and after all the air came out a glug of water quicky splashed on the alternator.  Immediately afterwards the boat wouldn’t start.  Dumb move on my part.  

1.  Does this engine normally need a purge or prime when completely dry?  And where should you do it?

2.  Did I majorly screw up by dousing the alternator for a second?  There are no error beeps or warnings and the temp sensor was not reading, which I assume is because there was not yet water in the engine, but maybe there is an overtemp safety?  The exhaust was already hot after 2 minutes of running with no water.  I thought you could run with a defective alternator but this is my first computer controlled boat.    

3.  Any ideas on What should I do next, assuming the no start continues?   I put it aside to dry out.

Thanks  

 

 

 

 

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JGTate

PROBLEM SOLVED, running great!   Went with the stock impeller and let the alternator dry out as well as pressed the main breaker reset and lanyard switch for good measure.   There is a HUGE difference in how much more water the plain stock impeller pulled through versus the globe.  Not sure why the previous owner liked them but will not be using those ever again.  

And when an impeller fails be sure to purge out the downstream line to the trans cooler and check the screen!

Thanks to all for the great tech tips!

 

 

 

 

 

 

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Chaabo

Congrats on getting all sorted out!

I ran the globe for exactly one day then replaced it with a std impeller.

Can’t recommend it, what a waste of money! On my first outing with the blue impeller my engine overheated while idling off the boat lift to the slalom course. Never had that issue with a std impeller.

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