Prop barrel wobble and rubbing inside the housing on new 4-strokes

[Highcentered]

THIS IS NOT ISOLATED TO JUST ONE MOTOR! I have a habit of turning the prop on motors when I'm walking through BPS. Seems like just about every one of them wobbles and rubs inside the housing. These are Mercury props on Mercury motors. This issue isn't isolated to just one size motor either. I've had it happen with a 50hp, my 75hp, and a new 115hp Pro XS 4-stroke. Why is this happening on a brand new motor with zero hours? On mine you can hear it rubbing when in reverse. It's a lot louder with a stainless prop. Is there a recall I don't know about? This issue would likely make selling a boat with a Mercury 4-stroke kinda hard. If you want to see exactly what I'm talking about just walk around a dealer and spin the props on the Mercury 4-strokes. Almost guarantee you'll find one that does what I'm describing. In addition, wouldn't a wobbly prop shaft on a brand new motor in the showroom indicate something bad wrong going on at the factory? Just wondering if anyone else has noticed this. Basically, it's as if the prop shaft is pre-bent before it ever gets put to use.

[EuropeanAM]

Are the majority of the engines at and/or from one dealership?

What hub kit has been installed in each propeller, and what was the prop but torqued to?

[Highcentered]

These are at the same dealer. Mine came from a different location but same group of people. My motor came with the standard Black Max prop but does the same thing with the new stainless Powertech prop. The Black Max prop had the kit where a small piece went in the top to snug it up. The Power Tech is snug the full length of the splines. Hope that makes sense. My prop lingo is really rusty. No clue on torque. The aluminum prop was installed both times by the dealer (when new and when motor was serviced). The stainless by me. Most likely torqued the same way I did by just snugging it up. Hopefully I can get this figured out. This is the first time I've ever seen anything like this in over 30 years of being around boats.

[2500]

These are at the same dealer. Mine came from a different location but same group of people. My motor came with the standard Black Max prop but does the same thing with the new stainless Powertech prop. The Black Max prop had the kit where a small piece went in the top to snug it up. The Power Tech is snug the full length of the splines. Hope that makes sense. My prop lingo is really rusty. No clue on torque. The aluminum prop was installed both times by the dealer (when new and when motor was serviced). The stainless by me. Most likely torqued the same way I did by just snugging it up. Hopefully I can get this figured out. This is the first time I've ever seen anything like this in over 30 years of being around boats.

Power tech prop not a Merc prop. All their motors are bad? All are scrubbing are you sure that it’s not extra paint on prop or prop area.

[Highcentered]

Both the oem Black Max prop and the Power Tech prop rub on mine. I just find it strange how every one of them I've spun seem to do this at BPS. Only time I notice mine doing it is in reverse so I guess the little bit of slack in the gearing clears it just enough when pushing. Next time I think about it I'm going to go turn every prop in there and if I find even just one rubbing I'm going to go ask to speak with a tech about it. For all I know the nut is too tight and causing it to sit crooked on the spindle.

[Bill Reynolds]

I don't have a 4 stroke and no experience with them but I did notice in another post that there is a plastic ring inside the exhaust hub on the mid range 4 strokes. I wonder if this is what you feel rubbing?

[Highcentered]

There's a ring in mine kinda like that that it rubs on. Other than this little annoyance the motor is incredible. Like I said above next time I think about it I'm going to see if the prop nut is just too tight.

[SilverFox579]

Like I said above next time I think about it I'm going to see if the prop nut is just too tight.

Going to have use a torque wrench when installing props to know if they're too tight (or not tight enough). Just "snugging them up" could leave a prop nut under or over torque spec. Hub type matters too.

[billnorman1]

Are we thinking thrust washer missing here?

[EuropeanAM]

There is intentional play in the FT-III and FT-IV hub kits. You can move the prop around on the shaft a bit when stationary, but with the prop underway (under power), the forward thrust forces it firmly/squarely on the thrust washer surface.

Just too many variables at play here with too many engines. If we bring it back to ONE engine (per forum Guidelines), and identify that engine/prop/hub kit, we might be able to determine something.

[Wall-I]

Maybe this will explain a little of it.

[EuropeanAM]

Good info... except we shouldn't be seeing Reflex Hub Kits on these engines.