Impeller Size

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btomlins

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I'm confused on which is the correct impeller for my 1995 Evinrude 65/90 1768 Roughneck boat. I believe it is a M73 jet on it. I had a boat mechanic tell me I had the wrong impeller but didn't tell me what it was supposed to be. Right now it has a 7 3/8" impeller. Motor seems kind of sluggish and motor doesn't get to full RPM's. Most people say the motor is tired. It has just been rebuilt a year or so ago. I believe I need a 7 3/16" impeller. Will that little bit of difference let the motor get up to full RPM? Impellers are a little different than props as there is literally hundreds of propeller options not so much on impellers. Any thoughts?

bryan
 
I would check directly with Outboard Jets (https://www.outboardjets.com) to verify which model jet drive you have. It depends if you have the 90 degree V4 or the 60 degree V4 but they both look like R model jet drive which shows as 7-3/8. But the R85 shows a 3 blade impeller and the R4-60 shows as a 4 blade so it depends on your motor layout. You can't go to a 7-3/16 impeller, it will leave a large gap and give you very little thrust.

Model identification for Johnson-Evinrude
https://outboardjets.com/download/jet_drive_kits/Johnson-Evinrude-Blue-Binder-2015-PRICE-UPDATED-102716.pdf

Impeller identification for Large pump
https://outboardjets.com/download/large_series/Large%20Intake%20and%20Impeller%20Size%20Determination%20Updated.pdf
 
If I understand this correctly you must size your liner and impeller together. If so there shouldn't be a gap.
 
Those links is where I've been looking too. The m85-73 lists a 7 3/16 impeller with a 137 liner or a 106.24 impeller.
 
Call Brian at Outboard Jets and speak directly. He was very helpful with my older and out of production jet.
 
Yes the liner size has to match the impeller size. There are a couple different 7 3/8 impeller sizes. Looks like there's two 3 blades the 7 3/8 and a 7 3/8D both offered in stainless and aluminum.
JL8Jeff is right and your pump should be a R series pump unless it a crossflow v4 put I think they used the R pump also.
 
btomlins said:
Those links is where I've been looking too. The m85-73 lists a 7 3/16 impeller with a 137 liner or a 106.24 impeller.

You can't tell which motor manufacturer the m85-73 is for, you have to first go to the Johnson/Evinrude page and you can see the R85-92 or the R4 60 depending on which block you have.
 
Take a look at the top of the second page of this PDF. Says Evinrude/Johnson 85-100hp. Item 59 is the impeller. On the bottom of the page says date of document is 17th Sept 1997 I believe. My motor is a 1995 V4 Crossflow.

View attachment MODEL M.pdf
 
I found the model number on my jet drive and it is a R series. The issue that I'm having now is the liner that is currently in the unit is the bolt in style and not a flanged style. Not sure why it is the wrong liner as I purchased the boat used? The pick up shoe is completely different between the M and the R85. Mine is like the one on the M series page. On the Outboardjets .com pricing page they list an intake casing part number 104 that is not the flanged unit for the M series and will fit a 7 3/16 liner. The part number for an R series is 1332 and is a 7 5/8" intake. Im really confused now! Still think I need a 7 3/16th lmpeller. I guess I will give Brian a call.
 
Yeah, it sounds like you have a mismatch of parts there. You might want to take some good pictures and then call them to see what parts you should have. Are you having trouble planing off or does it seem to not have as much thrust as you would expect? It could be shimmed improperly and not have tight enough clearance between the impeller and liner.
 
btomlins said:
I'm confused on which is the correct impeller for my 1995 Evinrude 65/90 1768 Roughneck boat. I believe it is a M73 jet on it. I had a boat mechanic tell me I had the wrong impeller but didn't tell me what it was supposed to be. Right now it has a 7 3/8" impeller. Motor seems kind of sluggish and motor doesn't get to full RPM's. Most people say the motor is tired. It has just been rebuilt a year or so ago. I believe I need a 7 3/16" impeller. Will that little bit of difference let the motor get up to full RPM? Impellers are a little different than props as there is literally hundreds of propeller options not so much on impellers. Any thoughts?

bryan


Do you still have this boat and are you interested in selling it?
 
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