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AQ130C water pump impeller failure

am_dew

am_dew

Advanced Contributor
The impeller in the water pump on my AQ130C engine fried yesterday. How does one make sure that there are no pieces of the impeller fins downstream in the cooling system? Thanks.
 
By the way, the reason I asked is because I replaced the bad impeller with a spare (used but in good shape) and I still did not get any water flow through the engine. This all took place on the water after cruising for about 2 hours without any cooling issues. We ended up getting towed about 5 miles back to the launch ramp. The day did not end well, that's for sure. Now, to figure out how to fix it.
 
There is a metering port in the exhaust elbow where the "excess" water is allowed to flow into the exhaust stream. Check there...
Also... check in the T'stat housing. Are you sure that the cam gear is driving the impeller? Did you insert the key in the impeller when you replaced it? Is the pump drive shaft indexed (and in good shape) to the cam gear?
 
sandkicker said:
There is a metering port in the exhaust elbow where the "excess" water is allowed to flow into the exhaust stream. Check there...
Also... check in the T'stat housing. Are you sure that the cam gear is driving the impeller? Did you insert the key in the impeller when you replaced it? Is the pump drive shaft indexed (and in good shape) to the cam gear?
Click to expand...

While the water pump cover was off and with the spare impeller installed, I cranked the engine for a few seconds and the impeller spun.
 
What sort of issues might I have after removing the bolt that goes through the center of the oil cooler so I can check if there are any chunks of the impeller caught in the strainer? (I am assuming there is a water strainer on the water input side of the oil cooler based upon parts diagrams)

I know those copper pipes can be difficult to get sealed back up and I am presuming the copper pipe's seal will be compromised once I remove the end cap on the water input side of the cooler.

Will removing the cooler's center bolt also upset the seal on the end cap on the water output side of the cooler?
 
No strainer, but the bundle of small tubes that constitutes the cooler, makes an effective block to larger pieces of "stuff"... Many years ago, I had to install a sea water strainer on the input of the raw water pump to keep junk out of the oil cooler's water circuit. Ever since, I've installed seawater strainers of one type or another on all my boats (except my Merc drive Bertram 25... a moment of silence for a great boat gone before its time...) . My current boat has an external wedge shaped strainer mounted externally on the hull... 14 seasons and no crap in engine raw water circuit issues. This arrangement also improves impeller life since running it aground briefly on an unmarked bar ( I boat on Barnegat Bay... anyone who claims to not bump the bottom on occasion either lies or never leaves the slip) does not result in sand and crap being sucked into the impeller and damaging it.
 
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Thanks. Will removing the water input side end cap on the cooler upset the seal on the water output side? Or will that end cap stay in place undisturbed? I'm just trying to get an idea of what I may face when I remove the input side's cap.
 
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sandkicker said:
No strainer, but the bundle of small tubes that constitutes the cooler, makes an effective block to larger pieces of "stuff"... Many years ago, I had to install a sea water strainer on the input of the raw water pump to keep junk out of the oil cooler's water circuit. Ever since, I've installed seawater strainers of one type or another on all my boats (except my Merc drive Bertram 25... a moment of silence for a great boat gone before its time...) . My current boat has an external wedge shaped strainer mounted externally on the hull... 14 seasons and no crap in engine raw water circuit issues. This arrangement also improves impeller life since running it aground briefly on an unmarked bar ( I boat on Barnegat Bay... anyone who claims to not bump the bottom on occasion either lies or never leaves the slip) does not result in sand and crap being sucked into the impeller and damaging it.
Click to expand...

.....further: thru raw water hull pickups. Possibly more important with raw water cooled engines where ingested sand and mud can accumulate in the bottom of the block's water jacket, leading to problems at winterizing time.
 
am_dew said:
Thanks. Will removing the water input side end cap on the cooler upset the seal on the water output side? Or will that end cap stay in place undisturbed? I'm just trying to get an idea of what I may face when I remove the input side's cap.
Click to expand...

It's been a very ling time since I worked on one of these setups ( 1978!) and as I recall, it does cause a bit of a challenge at reassembly time. At the time I last did this, I was considering replacing the tube/washer press fit system with screw in barbed hose fittings and hose instead of pipe. This would necessitate finding a hose barb of a convenient size and tapping the housing so the fitting would screw in. I sold the boat ( got a bigger boat) before I got around to doing that. Ricardo is the resident expert on these.
 
I finally got around to troubleshooting this today...

  1. Started off by installing a new impeller and water pump cover cover gasket.
  2. I then driveway tested by placing the outdrive in a large tub of water and idled engine. EVentually, the temp went to bottom of "red" om the temp gauge. Shut engine off.
  3. I then attached garden hose in input side of water pump...I noted that no water came out of hose leading back to outdrive when I removed it. Idled engine with hose valve on relatively low pressure....no temp issues...temp gauge stayed in the low part of the green area. Shut engine down and turned water off.
  4. Removed garden hose from input side of water pump and water drained from it.
  5. Ran test in item 2 again...same results as I got before...engine temp got too hot.
  6. In an attempt to determine if the water pump was capable of sucking up water, I placed a 5 foot hose into a bucket of water right next to the boat. Started engine and the engine temp got too hot. I also noted before I shut the engine off, that there was not water coming out of the exhaust port on the outdrive.
So, based on the result I got from the test in item 6, the water pump is not doing it's job. Or am I wrong to think that the water pump should be able to pull water from a bucket using a 5 foot hose between the bucket and water pump?

I looked carefully at the insides of the water pump and did not see any obvious scoring. I also looked at the cover and while it has some minor scoring, it seemed in good shape. Also, while I had the pump cover off and impeller installed, I started the engine to make sure the impeller was turning and it was.

I have a new pump cover coming this week and will install it and try the test in item 6 again to see if a new cover helps.

Otherwise, I would presume I am looking at replacing the pump which is a Volvo 829895, of which Volvo wants $453 fior but there seems to be a Johnson Pump replacement 10-35098-3 F4B-9 for about $225.

Comments?
 
I and a similar problem to yours after replacing the impellor i found that very little water coming out of the exhaust port so i removed the elbow on the end of the outlet manifold and found it be restricted badly with rust so i cleaned it out with a flexible hacksaw blade pulling it backwards and forwards over a couple of hours and this solved the problem
This was the same motor as yours
 
tpcrichard said:
I and a similar problem to yours after replacing the impellor i found that very little water coming out of the exhaust port so i removed the elbow on the end of the outlet manifold and found it be restricted badly with rust so i cleaned it out with a flexible hacksaw blade pulling it backwards and forwards over a couple of hours and this solved the problem
This was the same motor as yours
Click to expand...

Thanks for your comment. My test using the garden hose attached to the water pump and I got water out of the exhaust port and no overheating, seems to imply that water is flowing through the exhaust manifold without restriction. Also, the fact that the water pump is not sucking up water from a bucket, also implies that there could be a problem with the pump itself. I could be wrong however.
 
Yes it would flow with the garden hose but the pressure from a garden hose is a lot higher than the pump can generate.
I would note that i did not test your way but had the boat in the lake at the time as when i tried the muffs it would not pick up or flow with them connected
The pumps on these motors are so simple not a lot can go wrong with these bar the impellor and the clearance with the pump housing mainly the the front cover plate and gasket size
 
Just for the record, the pressure from the garden hose was purposely set pretty low, but either way water is still being pushed though the system. I'm next going to detach the output side of the pump and attach a hose that I will run into the bilge (with drain plug out of course), then re-run the "water from a bucket" test to see if the pump will suck up water and discharge it out the fore mentioned hose and into the bilge.
 
am_dew said:
Just for the record, the pressure from the garden hose was purposely set pretty low, but either way water is still being pushed though the system. I'm next going to detach the output side of the pump and attach a hose that I will run into the bilge (with drain plug out of course), then re-run the "water from a bucket" test to see if the pump will suck up water and discharge it out the fore mentioned hose and into the bilge.
Click to expand...

I had the same issue after changing the impeller this spring. When I removed the pump the intake side drained all the water out as well as the the outflow side. I could not get the pump to prime. I ended up filling all the lines with water while I had muffs hooked up to the outdrive and the pump was able to prime.
 
otnot said:
I had the same issue after changing the impeller this spring. When I removed the pump the intake side drained all the water out as well as the the outflow side. I could not get the pump to prime. I ended up filling all the lines with water while I had muffs hooked up to the outdrive and the pump was able to prime.
Click to expand...

How did you fill the lines with water? There is no place to inject water into the cooling system on an AQ130C unless you remove the line from either the input our output side of the water pump.
 
am_dew said:
How did you fill the lines with water? There is no place to inject water into the cooling system on an AQ130C unless you remove the line from either the input our output side of the water pump.
Click to expand...

I removed both hoses from the pump and filled the system.
 
Just so I am clear, after removing the hoses from the pump, you pushed water through the copper tube that attaches to the hose on the output side of the pump and leads to the oil cooler until you saw water coming out the exhaust outlet on the outdrive?
 
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