Changed BIII pump impeller... now have no water pressure/flow

[gnealon]

Guys, this is driving me nuts. I changed both impellers on my BIII raw water pumps (this is my second time doing it w/ no issues last time) and now im not getting any water out the drive housing/props (well sorta).

So when i first fired them up after a little while water started flowing out the drive housing (soapy water everywhere from impeller install) so i figured i was good. That eventually stopped and now the temp just slowly creeps up to over heat range.

I pulled the freeze plug off the pump on the input side and water was pouring out w/ muffs on so I think i have water pressure.

I pulled hoses off thermostat housing and filled block w/ water thinking maybe i have some air block or something.... no luck.

My PSI starts at .3 and goes to 0 after i filled block, so maybe it was temporary.

I'm at a loss guys, do i have a prime issue? air lock? i dont think i smoked the impellers since i had some water flow and when i manually turn the pully on water pump it sounds fine.

Any ideas? Thanks in advance and sorry for the long post, just wanted to get everything i did out to help.

 

[mainstream]

Guys, this is driving me nuts. I changed both impellers on my BIII raw water pumps (this is my second time doing it w/ no issues last time) and now im not getting any water out the drive housing/props (well sorta).

So when i first fired them up after a little while water started flowing out the drive housing (soapy water everywhere from impeller install) so i figured i was good. That eventually stopped and now the temp just slowly creeps up to over heat range.

I pulled the freeze plug off the pump on the input side and water was pouring out w/ muffs on so I think i have water pressure.

I pulled hoses off thermostat housing and filled block w/ water thinking maybe i have some air block or something.... no luck.

My PSI starts at .3 and goes to 0 after i filled block, so maybe it was temporary.

I'm at a loss guys, do i have a prime issue? air lock? i dont think i smoked the impellers since i had some water flow and when i manually turn the pully on water pump it sounds fine.

Any ideas? Thanks in advance and sorry for the long post, just wanted to get everything i did out to help.

Hello Here is a service bulliten from mercury on flushing bravo 3.0l 6 cylinder and v8 i dont know if thids helps bit it sounds like you have to bring up rpm but im not a boat mech
http://forums.iboats.com/showthread.php?t=44372

 

[gnealon]

Hello Here is a service bulliten from mercury on flushing bravo 3.0l 6 cylinder and v8 i dont know if thids helps bit it sounds like you have to bring up rpm but im not a boat mech
http://forums.iboats.com/showthread.php?t=44372

hey, thx for the post. that's interesting. ill try and run it around 1200 for a bit to see if it pulls more water through.

 

[jason78]

Was the pump cover worn down bad inside? If so the pump may be unable to prime itself since it cannot get a good seal. This is a known issue with the brass pumps.

Are you sure you bent the vanes in the correct position when you installed them in the housing? If not you probably smpked them.

Are you sure you put the hoses back on correctly on the back of the pump?

Did you use Merc/Quicksilver impellers? I have heard a couple of times people used some West Marine brand impeller (may have been Sierra, not sure) and the toasted almost immediately.

Since it is the same on both engines, I would say it is most likely is either installation error, bad impellers or bad housings.

Jason

 

[gnealon]

Was the pump cover worn down bad inside? If so the pump may be unable to prime itself since it cannot get a good seal. This is a known issue with the brass pumps.

Are you sure you bent the vanes in the correct position when you installed them in the housing? If not you probably smpked them.

Are you sure you put the hoses back on correctly on the back of the pump?

Did you use Merc/Quicksilver impellers? I have heard a couple of times people used some West Marine brand impeller (may have been Sierra, not sure) and the toasted almost immediately.

Since it is the same on both engines, I would say it is most likely is either installation error, bad impellers or bad housings.

Jason

Jason, thanks man. Good suggestion on the pump cover! Mine had some decent grooves in it... i guess i should order the wear plate and play it safe. How bad do the grooves need to be for it to be an issue?

To answer some of your questions... put in quick silver impellers and 100% sure vanes are right direction. I'm paranoid of that, even took a pic w/ my cell before to make sure they go back correctly.

Also, I dont think its possible to reverse the hoses, they are two different sizes. That red tough input hose is on top on the smaller opening on the pump.

Anyways, thx again for the suggestions. Putting the wear plates on forces me to inspect the impeller again. Kills me to think about pulling those damn pumps again. Such a pia.

 

[David Paul]

If you had adequate pressure before you changed the impellers I think it would be doubtful that it would be grooves in the pump cover.

 

[jason78]

Jason, thanks man. Good suggestion on the pump cover! Mine had some decent grooves in it... i guess i should order the wear plate and play it safe. How bad do the grooves need to be for it to be an issue?

If you had adequate pressure before you changed the impellers I think it would be doubtful that it would be grooves in the pump cover.

I have read more than once where after an impeller change the pump failed to re-prime because of those grooves when there were no prior problems. I can only imangine this is because the old impeller has grooves worn down in it as well keeping the seal. When the new impeller is put in, the grooves are open because the impeller side is not worn with the pump cover.

To answer the OP's question though, I have no idea how bad the grooves can get before they start causing problems. This is only a possibility though. If you decide to do this I would only do one and see the results considering the difficulty of the job.

 

[Henry Boyd]

+1 we splashed yesterday with a new impeller. 0 to 1 psi water pressure. Fortunately I was able to bleed The air from the lines at the junction with the through hull and flush connection.


Sent from my iPad using Tapatalk HD

 

[gnealon]

Got it!!! I must have had a prime issue or air lock somewhere. I just kept the engine around 1300 RPM's and eventually the water pressure shot up to about 1.5 and water started pouring out of the drive.

Thanks everyone for the help! So glad I didn't have to pull those pumps again!