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(Another) Hardin pump issues thread...
I’ve had a ***** of a time getting this to prime. I’ve tried assembling with dish soap then marine grease instead, and new Merc impellers each time with the same result. The water is fed via a tee and garden hose right in front of the pump. I closed the valve before the sea strainer to force feed water into the engine but it still won’t pull if the valve is open and it just dumps out the drive. When i run my finger across the machined surface and it feels like like it was polished with 80grit and it crowns in the middle. Everything is brand new. https://cimg9.ibsrv.net/gimg/www.off...d9d6c79c6.jpeg |
No chance lines are on wrong? How are the dimensions to stock housing depth of bore and pinch area? |
Originally Posted by 14 apache
(Post 4692611)
No chance lines are on wrong? How are the dimensions to stock housing depth of bore and pinch area? |
The right port in the picture is out.to motor? |
I’ll check again when I get home. |
this actually can get confusing. sounds like you have the lines on backwards?
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on the mercury pumps the rotation is from the back not front
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Yes, from the back it is left hand rotation. They even give you handy instructions engraved on the back of the housing. The 90° fitting on the bottom is the output going to the engine. https://cimg6.ibsrv.net/gimg/www.off...6e4b935d1.jpeg |
I have take my out and work after holiday more with the Hardin housing! Use now Merc Housing to be safe in holiday.Michael
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is it me or is there a crack on the lower left port in the first pic?
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Originally Posted by sutphen 30
(Post 4692662)
is it me or is there a crack on the lower left port in the first pic?
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You can also see a bump in there about half way in where the port starts. Putting a straight edge on it it rocks back and forth about a 1/64”. Id think the rubber impeller could manage that difference. Im thinking of running something like a caliper home in there as the grooves really catch the fingernail. Any thoughts against that? https://cimg8.ibsrv.net/gimg/www.off...0a46ced9f.jpeg |
What did Hardin have to say about your issue?
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Originally Posted by rv
(Post 4692731)
What did Hardin have to say about your issue?
Its an otherwise beautiful piece and using the threading fittings allows me to eliminate any molded hoses and couplers/hose clamps. Going back to plastic would be a pain with my current hose routing. |
Originally Posted by rv
(Post 4692731)
What did Hardin have to say about your issue?
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Have you tried taking it to the ramp and bringing up the RPM to around 2,000?
We did impellers on my buddy's 575SCI's and couldn't get them to build any pressure on the hose. Put it in the water and brought the RPM up to 2,000 and it built pressure almost instantly. |
Originally Posted by c0ncEpT
(Post 4692754)
Have you tried taking it to the ramp and bringing up the RPM to around 2,000?
We did impellers on my buddy's 575SCI's and couldn't get them to build any pressure on the hose. Put it in the water and brought the RPM up to 2,000 and it built pressure almost instantly. |
Hardin was saying that it’s the “squish” on the ends that creates suction. The blades were completely smoked but the ends of the impeller look virgin. The wear plate had nothing but a little assembly grease on it. https://cimg4.ibsrv.net/gimg/www.off...74421af0b.jpeg https://cimg5.ibsrv.net/gimg/www.off...18be7ea65.jpeg |
Do you have a caliper to measure the depth of the stainless housing?? Might be to long. |
Are the swirl patterns on both end plates uniform? After I rebuild mine, I turn the pulley by hand before reinstalling it. Does yours have that freedom of movement? It should be tight but turn by hand. Silicone spray works really well instead of grease. |
Originally Posted by 14 apache
(Post 4692773)
Do you have a caliper to measure the depth of the stainless housing?? Might be to long. https://cimg0.ibsrv.net/gimg/www.off...a4f7ec58e.jpeg https://cimg1.ibsrv.net/gimg/www.off...121135d35.jpeg |
https://cimg7.ibsrv.net/gimg/www.off...18847f22d.jpeg It looks like nearly an 1/8” gap. This is the oem Merc impeller. I got a Sierra one laying around and brand new measures even smaller. |
You have this wear plate in the back of the pump correct?
https://cimg3.ibsrv.net/gimg/www.off...f51ea4ed6.jpeg |
Originally Posted by IGetWet
(Post 4692827)
You have this wear plate in the back of the pump correct?
https://cimg3.ibsrv.net/gimg/www.off...f51ea4ed6.jpeg |
Originally Posted by IGetWet
(Post 4692827)
You have this wear plate in the back of the pump correct?
https://cimg3.ibsrv.net/gimg/www.off...f51ea4ed6.jpeg |
The Hardin email mentioned it, “inner wear plate”. I do have the same pump and thought as I was putting it together how the pump probably wouldn’t work at all if that small piece was missed.
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I wonder if Brembo has the same problem? |
Originally Posted by IGetWet
(Post 4692856)
The Hardin email mentioned it, “inner wear plate”. I do have the same pump and thought as I was putting it together how the pump probably wouldn’t work at all if that small piece was missed.
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Originally Posted by ph1971
(Post 4692861)
I wonder if Brembo has the same problem? |
On to another thing...whatcha all think about the machining on the inside? Seems like it would wear on the rubber a bit. |
Mine looked the same and did not wear the impeller. Changed the impeller out this spring after 2 seasons and the impeller still looked new. Never had any pressure issues running this pump. In fact, my pressure picked up over stock at idle. And yes, that inner wear plate would be easy to miss. And on my pump was a bear to get the old one out to replace with the rebuild kit.
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Fair enough then! And thanks for everybody’s help on sorting out my boneheaded oversight. Ive ordered the plate and will post the results. I may still run a small hone in that baby just because. ;p |
I have the same pump. I change my impeller once a year as maintenance . Never have had a problem with any part of it. Jeff Wurl |
Originally Posted by Baja Rooster
(Post 4692824)
https://cimg7.ibsrv.net/gimg/www.off...18847f22d.jpeg It looks like nearly an 1/8” gap. This is the oem Merc impeller. I got a Sierra one laying around and brand new measures even smaller. |
Originally Posted by 14 apache
(Post 4692976)
I hope harden gives you something for the pain Glad it was an easy fix. |
Originally Posted by Rookie
(Post 4692995)
They did give him something for the pain... the wear plate that he forgot to install. lol
Glad it was an easy fix. |
Thin coat of white lithium is all I have ever used to pre-lube any impeller in any housing. I believe the Hardin rebuild kit also suggests using lithium grease.
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Originally Posted by Baja Rooster
(Post 4692945)
Fair enough then! And thanks for everybody’s help on sorting out my boneheaded oversight. Ive ordered the plate and will post the results. I may still run a small hone in that baby just because. ;p |
I've been running this pump on my 525 for years with no problem. Used to change impeller every year but it always looks like new so now I do it every 2 years.
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water base KY or glycerin to install impellers, Johnson pumps has done many studies on this and have found glycerin to be the best for installing impellers. Glycerin -- It washes out at start up very very quickly - many other products do not wash out very quickly. And dish soap exacts the oil out of impellers. All rubber products are a form of an oil base .
Johnson includes the glycerin in every impeller kit they sell for a reason. Like I said they tested everything Actually tech speaking clean water is the best for impellers no matter how you slice it because thats what they live in 24 / 7 Impellers and the housing is all about tolerances - when wrong it does not work nor flow correctly |
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