1996 Horizon 220 5.0Fi raw water pump issues.

RobRoller

Cadet
Joined
Aug 31, 2020
Messages
23
I have read through everything I could find on here about the VP raw water pump issues people have dealt with on the SX-M platform and I think i have exhuasted all options save for replacing the entire pump. The only thing i can think of prior to that is to "face" the inlet/outlet plate as i has a tiny amount of wear. When I replaced the impeller i didn't think that small amount of wear would stop it from working at all? I put clear tubing before and after the pump and can clearly see it is not sucking water and pushing through the pump. I connected garden hose to inlet side to lower unit and it flows freely so no blockage, and I just replaced the seals for the copper tube which was perfect as well. Anyone else run into this issue with a new impeller?20210402_191016.jpg20210402_190714.jpg20210402_190740.jpg20210402_190925.jpg
 

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Scott Danforth

Grumpy old guy who plays with boats
Joined
Jul 23, 2011
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34,283
How are you testing? Make sure you are testing with the boat in the water or with muffs

Dress the face and the cover

Check the inlet fitting io the drive itself. The ine the hose connects to. If that fitting is corroded or broke, it wont draw water
 

RobRoller

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Aug 31, 2020
Messages
23
Testing out of water in a huge tote of water so water inlets are about 5 inch below water line. I tried the muffs that came with the boat cheap plastic ones that i drilled so the hole is bigger and neither with the muffs or in the tote would pull water to the pump. I disconnected the hose from the transom and hooked to garden hose and it finally kept the exhaust risers cool, but temp guage on cluster climbed way up to the line below 240. Temp gauge is terrible as half way mark is 150 then there is 2 or three lines then 240degrees.
 

RobRoller

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Aug 31, 2020
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23
I also faced both sides of the pump with no change, I even clocked the pump on the bracket so the inlet/outlet were at the top instead of bottom.
 

alldodge

Supreme Mariner
Joined
Mar 8, 2009
Messages
32,125
The pump doesn't suck much at all, and putting it in a tote even that high is not enough. On the hard it should always be with muffs

Since muffs do not work its either the muffs (cheap ones, something wrong with them) or there is a restriction between the drive and the pump
 

Lou C

Admiral
Joined
Nov 10, 2002
Messages
7,241
If you have the dual inlet muffs with the hard rubber rectangular muffs they might not allow the pump to prime. I had trouble with those and switched to the Merc/Quicksilver round ones made out of much softer rubber. They fit better and the impeller primes easily. With the Volvo impeller way up on the engine you need good fitting muffs for it to Prime.
The other things that can cause problems are air leaks into your raw water hoses and a cracked plastic water nipple in the pivot housing. Also, inside the drive there is a water tube connecting the water intake area with the upper gear housing, there are rubber grommets on either end of this tube that can rot over time and cause air leaks.
 

ripjmk

Seaman
Joined
Feb 26, 2019
Messages
54
Have you replaced the pump shaft seal? If that lets air in you can loose prime in the pump. Also have you checked your thermostat is opening and all the housing ports are clear, weird to have cool risers and high engine temp if they are working.
 

cptbill

Chief Petty Officer
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Oct 6, 2012
Messages
405
It might be possible that your having a problem with the main engine water pump as well
 

RobRoller

Cadet
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Aug 31, 2020
Messages
23
Have you replaced the pump shaft seal? If that lets air in you can loose prime in the pump. Also have you checked your thermostat is opening and all the housing ports are clear, weird to have cool risers and high engine temp if they are working.
Yes i replaced the shaft seal and watched for leaks and it looks good.
 
Joined
Jan 21, 2020
Messages
22
We just replaced impellers on the same type pump and we had much more wear than you show. We were going to re-face both sides, but we weren't sure about tolerances and didn't, we just put in the new impellers and they seem to pump just fine. I did use a little sealant on the back plate as I was worried about air getting in. We are in a wet slip and water constantly flowed out of the hose when off, so it was primed with water up to the pump once I put the hose back on. Here is an album of pix that shows the wear we had: https://photos.app.goo.gl/fa4ScoXhvASQwhCJ8
 

RobRoller

Cadet
Joined
Aug 31, 2020
Messages
23
It might be possible that your having a problem with the main engine water pump as well

We just replaced impellers on the same type pump and we had much more wear than you show. We were going to re-face both sides, but we weren't sure about tolerances and didn't, we just put in the new impellers and they seem to pump just fine. I did use a little sealant on the back plate as I was worried about air getting in. We are in a wet slip and water constantly flowed out of the hose when off, so it was primed with water up to the pump once I put the hose back on. Here is an album of pix that shows the wear we had: https://photos.app.goo.gl/fa4ScoXhvASQwhCJ8
Good to know i appreciate your response. I was wondering if i used the wrong seal as it came with two white seals and one paper seal. I will try some sealant to see if it is a sealing issue. If not im going to bite the bullet and buy a new one.
 
Joined
Jan 21, 2020
Messages
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Good to know i appreciate your response. I was wondering if i used the wrong seal as it came with two white seals and one paper seal. I will try some sealant to see if it is a sealing issue. If not im going to bite the bullet and buy a new one.
Our impeller didn't have the correct gasket, so I reused the old one and just smeared a little sealant on both gasket surfaces. We also lubricated the impeller with vaseline even though it wasn't going to run dry at all. Just for your info.

Before I put the fan belt and output hose back on the pump, I could turn it by hand it it would output water. So it helps to have that water primed in the input hose right at the pump. If you don't want to mess with the pump and parts anymore, there is a person on ebay who rebuild them and sells ready to bolt on pumps.
 

RobRoller

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Joined
Aug 31, 2020
Messages
23
Our impeller didn't have the correct gasket, so I reused the old one and just smeared a little sealant on both gasket surfaces. We also lubricated the impeller with vaseline even though it wasn't going to run dry at all. Just for your info.

Before I put the fan belt and output hose back on the pump, I could turn it by hand it it would output water. So it helps to have that water primed in the input hose right at the pump. If you don't want to mess with the pump and parts anymore, there is a person on ebay who rebuild them and sells ready to bolt on pumps.
Yep, I saw he had brand new ones for $300 so I think I will go that route.
 
Joined
Jan 21, 2020
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Not a good idea to use any kind petroleum product on the impeller. You want water soluble like glycerin (ky jelly)
Thank you @alldodge, my brother said the same and it is better safe to use the mildest option than be sorry. When I searched for the type of rubber used on impellers it seemed to be oil-resistant, but I will check them and clean them off.
 

RobRoller

Cadet
Joined
Aug 31, 2020
Messages
23
Well i swapped the gaskets and put some aviation sealant on either side of it and slapped it back on the boat. I put both ends of the hoses into a bucket of water and poored some water in the hoses to prime the pump. I fired it up and immediately got some movement of water! After about 10 seconds it was really moving the water at idle. Now i am going to hook everything back up and see what happens.
 
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