Home › Forum › Ask A Member › 1960 Scott 7.5 hp impellers
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jeff-register.
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May 5, 2023 at 9:48 pm #275955
When I went through this subject motor, I installed two new Discount Marine
impellers in it. (Bailer motor)
When I first fired the motor up a couple of days ago in the test tank,
it would pump a little water at idle, but when I revved it up, it would
quit pumping water.The original impellers were 12 vane, the new ones are 10 vane, and
a little larger OD.I tore the powerhead back off the motor this morning, and put the lower unit
in the test tank, and spun the driveshaft over with my drill.
I got the same results with the drill as I did running the motor. ….
pumps some water at slow rpms, quits pumping when you speed it up.Next I took the pump assemble with original impellers, from one of
the parts motors, rigged up a discharge line, spun it with a drill in the
tank, holding the impellers about two inches below the water line,
and it pumped great.I then put those original impellers back in the LU on the subject motor,
and did the drill test. It seem to pump just fine.
During both test with the pumps in the lower unit, I had a hose on
the bailer barb, hanging down in the water.
When I removed the bailer hose, the main pump didn’t pump worth
beans.
I’ve never seen documentation, but is the bailer bard suppose to be
capped off when not “bailing”?
Only conclusions I’ve come to is these new replacement impellers
don’t work near as good as the original design…… unless
I’m missing something.
Anyone else use these Discount Marine Impellers for the Scott low profile
7.5 / 9 hp motors, and have them work good?
Thanks.Testing with new replacement impellers.
Quits pumping water when sped up. Strange.
https://youtu.be/UNfK0dKizOwPumps more water with the old impellers re-installed. Doesn’t pump good though when bailer hose is removed.
https://youtu.be/H7kYvgYeACwBailer pumping with original impellers, It did not “bail” with new replacement impellers
https://youtu.be/X2hQtJDNEOwPrepare to be boarded!
May 6, 2023 at 6:02 am #275961That’s good information but very discouraging news. I have the same impellers in my nine McCullough. I guess my lower is going to come back off, after all. What did we pay for those things? Was it like $75 for a pair?? I guess it beats spending $75 at a bar. Or does it?
Long live American manufacturing!
May 6, 2023 at 9:25 am #275963Bill, I paid $69.95 for the pair of the Discount Marine impellers.
I’d give yours a try before pulling it apart,,,,,,,, your
luck may vary! Besides…….. what would be “Plan B” if
you do have to pull it back apart….. unless there’s other
alternate impellers to try?I have plenty of yard work to do while I ponder these matters
of life……. or maybe I should ponder them at the bar instead, lolThat’s good information but very discouraging news. I have the same impellers in my nine McCullough. I guess my lower is going to come back off, after all. What did we pay for those things? Was it like $75 for a pair?? I guess it beats spending $75 at a bar. Or does it?
Prepare to be boarded!
May 7, 2023 at 11:59 am #275991The 10 blade impellers don’t seem to work very well; if at all. From what I have read…. It has to do with the blades being too close together in relation to the input area in the impeller housing.
May 7, 2023 at 12:05 pm #275992The 10 blade impellers don’t seem to work very well; if at all. From what I have read…. It has to do with the blades being too close together in relation to the input area in the impeller housing.
Thanks, that would make sense.
Makes one wonder though why they’re still being sold???Prepare to be boarded!
May 7, 2023 at 12:13 pm #275993Yes it is discouraging. I have a few 16HP Scotts and the impeller issues are a bit daunting. Even the people who are in the business of selling odd impellers don’t want to do the Scott variety on the bail-a-matics..
With current materials you would think that they could be made to be at least as good as the originals. Those original Scott impellers were TOUGH!
May 7, 2023 at 12:22 pm #275995Yes it is discouraging. I have a few 16HP Scotts and the impeller issues are a bit daunting. Even the people who are in the business of selling odd impellers don’t want to do the Scott variety on the bail-a-matics..
With current materials you would think that they could be made to be at least as good as the originals. Those original Scott impellers were TOUGH!
My original impellers were still “fair”, no cracks, etc.,
and out performed the new ones by a mile in my “drill test”.
I found 3 NOS impellers on EBay yesterday and ordered
two, so there may be 1 left if anyone wants it.
I’ve dumped way to much money it it already between
the impellers and carb / fuel pump kit, but I’m determined
to take at least one boat ride with it this summer!Prepare to be boarded!
May 7, 2023 at 12:48 pm #275997Just be careful that what they are selling are packaged correctly; some of the impellers on e-bay are out of their original packaging and may or may not be what the seller thinks they are. Scott also re-designed a couple of their impellers so “OLD NOS” and “NOT QUITE SO OLD NOS” might be different.
Also…..in case you don’t already know…..the old Sierra numbers for now discontinued Scott impellers have been re-issued for current Sierra impellers.
Here’s just one example:The original 18-3035 and the New 18-3035
May 7, 2023 at 6:42 pm #276015I’m about 99.4% these pictured are the correct impellers.
I just hope they’re not “hard as rock”!SCOTT McCULLOCH 7.5 HP 9 HP Outboard 73055 Water Pump Impeller NOS
https://www.ebay.com/itm/175674816337Just be careful that what they are selling are packaged correctly; some of the impellers on e-bay are out of their original packaging and may or may not be what the seller thinks they are. Scott also re-designed a couple of their impellers so “OLD NOS” and “NOT QUITE SO OLD NOS” might be different.
Also…..in case you don’t already know…..the old Sierra numbers for now discontinued Scott impellers have been re-issued for current Sierra impellers.
Here’s just one example:The original 18-3035 and the New 18-3035
Prepare to be boarded!
May 7, 2023 at 10:40 pm #276029Just wondering, could you remove every other vane to make the new ones work better?
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