# impeller work



## lemi (Jul 26, 2017)

has anyone heard of machining down a 6 7/8" auger to lighten it down to increase holeshot and topspeed I have heard it being done on merc 60/40 just curious if anyone has tried it and how it worked out


----------



## stinkfoot (Jul 26, 2017)

How would that work? It would still be moving the same amount of water.


----------



## lemi (Jul 31, 2017)

What they are doing is machining out the inside of the impeller to get more volume of water at take off


----------



## RiverBottomOutdoors (Jul 31, 2017)

I think you would loose top end with less mass and may cause deformation.


----------



## stinkfoot (Jul 31, 2017)

lemi said:


> What they are doing is machining out the inside of the impeller to get more volume of water at take off


 I can't imagine that amount of increased volume(<2%) would make any difference.


----------



## handyandy (Aug 3, 2017)

What do you have? four stroke 60/40 of some kind? Mercury/quicksilver who are the ones that make the three blade 6 7/8 stainless impellers. The new ones they make have been machined differently to allow the new 60/40 four chokes to be able to spin up to their optimal rpm range. THis is because the 60/40 four chokes didn't have the power to spin the old style non cut back stainless impellers in there optimal rpm range. So if you have an old style stainless impeller that isn't one of cut back ones don't cut it back sell it to me and go buy a new impeller that is a cut back one meant for a four choke. They're was thread with pictures of the two style 6 7/8 impellers that show the difference.


----------



## handyandy (Aug 3, 2017)

This is the one to look at to see the difference in the impellers they no longer make the two stroke style one merc simply started machining the impellers differently for four strokes and kept the same part number. 

https://www.forum.tinboats.net/viewtopic.php?f=85&t=42764

So if you have an old style one don't machine it just sell it to a two stroke guy and buy a new one off ebay this is the best price I have found for a new one that would most likely be a four stroke one.

https://www.ebay.com/itm/BRAND-NEW-OEM-MERCURY-MERCRUISER-IMPELLER-PART-47-855708T60-/262771660180?epid=2113606538&hash=item3d2e695594:gAMAAOSw6DtYWfbK&vxp=mtr


----------



## handyandy (Aug 3, 2017)

what some guys have done is polished their impellers and housings to make water flow better which can be good sometimes for a 1-3mph gain on top depending on how rough the castings were to begin with.


----------



## lemi (Aug 4, 2017)

I had the inside of my auger machined out and it has not been polished . I have gained 5 mph . also have heard of folks using those tornado nuts on the augers . I am running a 2017 merc 60/40 on a 1852 blazer . my top speed up river is now at 30mph


----------



## stinkfoot (Aug 4, 2017)

lemi said:


> I had the inside of my auger machined out and it has not been polished . I have gained 5 mph . also have heard of folks using those tornado nuts on the augers . I am running a 2017 merc 60/40 on a 1852 blazer . my top speed up river is now at 30mph




I stand corrected. How exactly does this work and what is a tornado nut?


----------



## lemi (Aug 6, 2017)

Tornado nut is a acron type nut to replace factory nut seems to cut down on turbulence in pump


----------



## lemi (Aug 7, 2017)

I have seen folks running a 7 3/16 in a 60/40 merc 4s running pretty darn good 
I think there are a lot of tricks out there if a guy is willing to play with them


----------



## Lil' Blue Rude (Aug 7, 2017)

lemi said:


> I have seen folks running a 7 3/16 in a 60/40 merc 4s running pretty darn good
> I think there are a lot of tricks out there if a guy is willing to play with them


Sorry but I'm calling BS. Maybe on a built 2 stroke 60/40 merc but not a 4 stroke. They can't pull a standard 6 7/8" up to rpm let alone a 7 3/16"
Lightening the inside of the might help some with throttle response but it won't cause it to pick up more water. Your removing material from the inside of the cone where the holes are drilled for balancing so it has no effect on how water flows.
The twister/tornado nuts do help with turbulence but it's not going to gain the average boat much if anything that they can feel, but every bit counts when your racing.


----------



## lemi (Aug 7, 2017)

You might say bs but I have seen it work like I said if folks are willing to experiment how knows what can be done for I have seen several 7 3/16 augers in 4s


----------



## lemi (Aug 7, 2017)

I am turning 5500 before and after auger work 
My boat has never bounced but I trim it will now


----------



## Lil' Blue Rude (Aug 7, 2017)

So how many rpms are these 4s with 7 3/16" turning? You said you had impeller work done, did Terry do your impeller?


----------



## lemi (Aug 8, 2017)

Terry did not do my auger I am running a 6 7/8 terry is doing the 7 3/16 I don't know what rpm they are running any boat I have been in that is running that auger has had no rpm gauge but seems to be turning pretty good


----------



## rotus623 (Aug 8, 2017)

Y'all talking about Terry Weaver? He cuts the impellers back, polishes them and polishes the liner. $150-$200 in work and lots of guys claim they are getting 3-4MPH out of the 60/40 4 strokes.

Y'all can call BS but this guy can work a pump. Check out SEMO jet boat enthusiasts on facebook.


----------



## lemi (Aug 8, 2017)

Yes terry has done several boats around and has had success . He is running the 7 3/16 auger in them


----------



## moelkhuntr (Aug 8, 2017)

Some guys have also lost MPH after he worked on the, myself included! So, don't count your chickens before they hatch! Better listen to Lil Blude Rude


----------



## rotus623 (Aug 8, 2017)

moelkhuntr said:


> Some guys have also lost MPH after he worked on the, myself included! So, don't count your chickens before they hatch! Better listen to Lil Blude Rude




Blue Rude knows his stuff, no doubt.

I have heard nothing but good stuff about "The Weave". I am curious to hear about where you started off and what you had done to lose MPH.


----------



## moelkhuntr (Aug 8, 2017)

I was running 40-42 GPS on lake and took Terry the NEW impeller and intake and linner and picked it up in a couple days. It was rough and looked like he had used a right angle grinder on it and took it to lake and run 34-35 GPS. Took that impeller out and bought NEW impeller and went back to lake and run 38-39 GPS. End of RANT! Listen to Lil Blue Rude, a what you can and can't do to a jet, he knows his stuff and he has done it by Hand!


----------



## Lil' Blue Rude (Aug 8, 2017)

Thanks moelkhuntr. Sorry to hear about your luck with the boat. This isn't the first time I've heard of someone having trouble with Weavers work in the past few weeks. He might gain some people but I've not been impressed with what work I've seen.
Lemi what year is your motor? Reason I made the comment about the 4 strokes not pulling a 6 7/8 is because mercury has started cutting around 3/4" off the trailing edge of the 6 7/8 impellers to increase the rpms vs the old quicksilver 6 7/8 stainless. Not all the 4 stroke mercs have these cut back impellers.


----------



## moelkhuntr (Aug 8, 2017)

Thanks Lil Blue Rude!!!! I just think people should know it's not a 100% fix to hand someone $100-$200 and come away with 3-5 mph gain on a jet! You can lose just like you can gain. Those last mph's are hard to come by!


----------



## lemi (Aug 8, 2017)

My merc is a 2017 . I am unaware of any cut back they did on auger sorry my bad. My gain has not only been from my interior auger work I am running very loose modified grates . The intend of this post was not to wage war on anyone buy to simply ask ? . My auger work was not done by terry (no him very well ) I took mine somewhere else just to explore options 
Thanks for all the input ...


----------



## Lil' Blue Rude (Aug 9, 2017)

Lemi I not trying to start a war on this either just stating what've I found out over the years from testing and tuning. You're right there is room for improvements in test and trying things.


----------



## lemi (Aug 10, 2017)

Blue rud I agree totally . what have you found works that works the best I know you can only put so much water through them or you will start going the other way there just not enough power there I wish someone could come up with something to beef up motor a guy can only do so much with the pump like I said I have not had my auger polished yet how much does that help and also is my auger you think one of the 3/4" cut back you think then


----------



## Lil' Blue Rude (Aug 12, 2017)

Lemi your motors new enough it should have the cut back impeller in it which explains why your getting 5500rpms. To me things like polishing or lightening a impeller, or a twister nut by its self won't be much of a noticeable gain but a bunch of small things added up should lead to a gain of some sorthow much depends on your setup.


----------

