Correct Prop Hub?

[pvanv]

I have a pair of Merc 115's on a 50-foot pontoon boat. The serial number is: 2B151536, model is 115F631D. The props are "loose" when the prop nuts are tightened all the way down. I replaced one prop and hub due to damage, and that one is now fine. So I got another hub kit of the same kind (Flo Torq), and I still have a loose prop. Ideas?

 

[pvanv]

Is there any way that the wrong hub kits were installed originally?

 

[Bondo]

Ayuh,.... Anything is possible,.... Do ya have the right thrust washer,..??

Were, Exactly is the slop,..??

 

[pvanv]

When I tighten down the nut until it bottoms on the prop shaft, there is still space fore and aft, and the prop is not held tight. It seems to fit the splines perfectly. The new prop and hub kit work fine. I can't see any differences in props or hub kits. I wonder whether Merc has a different hub kit that was used by accident.

 

[jimmbo]

Is the proper thrust washer installed?

 

[Bondo]

When I tighten down the nut until it bottoms on the prop shaft,

Ayuh,.... Sounds like yer missin' a part or 2, the nut should Never bottom out on the prop shaft,...

It should tighten against the prop/ hub parts,...

 

[pvanv]

Yup, I understand that. So, all parts are being used. Originally, both motors had loose props. Now, the one with the new prop and hub kit is OK, but the other one is still loose. Yes, it has the thrust bushing, and the washer at the very back. In forward, the loose prop does not hit the LU housing, so I assume the thrust bushing is OK. I wonder whether Merc has different hub kits, and if one is 1/4" shorter than another... and the original hub kits were different (wrong) from what was needed. They are supposedly both Merc props, so I am at a loss. In my experience as a Tohatsu/Nissan tech, I have never has this issue, so that's why I am asking the experts.

 

[Bondo]

Well,... You can see both of 'em, 'n We can't,....

I suggest ya pick yer favorite measurin' tool, 'n compare the 1 that fits, to the 1 that don't,...
That way you'll know which pieces are different, as there are obviously differences,....

I'd love to hear what ya find,....

 

[pvanv]

Yeah, but the boat is in storage right now, and tough to access. Just wondering whether anyone had seen this oddity before. Will get a measure and see what I find.

 

[jimmbo]

When I've seen propshaft nuts tightened all the way down and the prop still had fore-aft movement, there were parts missing, the wrong parts installed, or even the wrong prop installed. Without being there, or seeing pictures, part numbers, and part catalogs/lists, we can only give so much advice.

 

[Fun Times]

Notes: Serial number belongs to an MERCURY ME 115EXLPT COMMAND THRUST EFI 115EFI EXLPT 4

When I tighten down the nut until it bottoms on the prop shaft, there is still space fore and aft, and the prop is not held tight. It seems to fit the splines perfectly. The new prop and hub kit work fine. I can't see any differences in props or hub kits. I wonder whether Merc has a different hub kit that was used by accident.

Or maybe a mix up someplace....They offer many different part numbers and designs for many other outboard brands and different Flo-Torq numbers and names now as well. Such as Flo-Torq #'s 2, 3, 4 or flo-torq reflex hub kit which you being you that's in the marine field may want to have a watch of the following video just so you're aware of the proper way to install the reflex hub should one come your way.... https://www.youtube.com/watch?v=H4nTiGOcIvs

Maybe to try and help get a better grasp if things should seem to be lining up or not is if you happen to have the Mercury part numbers handy for both new and old props along with any of the flo-torq kit #'s you have/bought...Here's pretty much the list of flo-torq kit numbers that are out there, http://www.mercruiserparts.com/hub-kit-selection-chart

Maybe by chance Chigwalla or Yegboats has seen an oddity recently.

 

[Yegboats]

My first guess would be to check that the props you were sold weren't for the standard 115 gearcase since you have command thrust which has the larger gearcase. I've seen boat manufacturers ship boats with incorrect props installed from the factory on command thrust gearcases.
Other than that I agree with Jimmbo it would be nice to see some pics showing the casting #s
I'll try to take some pics tomorrow for eas comparison.

 

[Yegboats]

The standard Merc hub is 835257q1 or k1 Here is a close up pic of the splined aft adapter, and the forward thrust washer. The #s on them are 8m0042201,
and 12-835467-1

 

[pvanv]

Yes.

Motor serial number is: 2B151536, Model is 115F631D. The fore-and-aft slop was there from day one, 3 years ago. The manufacturer is confused, and claims that they always use Mercury props. This is on a 55-foot Sightseer pontoon ferry, that runs about 68 hours a week, and does a lot of backing. We'd damaged a prop and needed a replacement; I ordered and installed a 16Dx11P, 3-blade aluminum, [FONT=&quot]78112A45 prop, which came with a hub kit, and it fits perfectly. We had the damaged prop fixed at the local prop shop, and when re-installing it, used a 835257K9 hub kit. I didn't personally install the hub kit, so I can't confirm 100% that they used it, but that setup still has the fore-and aft slop. The original props are marked [/FONT]J 16 x 11P, and has an M in a recess. I assume that is a Mercury prop, but was surprised that there isn't a part number on the prop. Normally Mercury props have the part number stamped on them right where the pitch is on this one.

In the end, I suppose I could just order another 78112A45 prop and hub kit, but then I will want the original props as spares, and will want the correct hubs so they aren't sloppy.

 

[Chigwalla]

Maybe by chance Chigwalla or Yegboats has seen an oddity recently.

Funny you should ask...I had a new Whaler with a 75 that had that issue early in the year. I don't recall the details, but I'm pretty sure it was the wrong hub.

 

[Fun Times]

Found the answer for us all.

The fore-and-aft slop was there from day one, 3 years ago. Now ordered new 78112A45 prop, which came with a hub kit, and it fits perfectly.

Most likely that new prop came with a Flo‑Torq II (2) kit # 835257K1 which will fit nice and tight like we're used to feeling. This plastic hub shouldn't have a groove/spacing in the center like seen here, https://www.ebay.com.au/sch/i.html?...TRC0.H0.X835257K1.TRS0&_nkw=835257K1&_sacat=0

Had the damaged prop fixed at the local prop shop, and when re-installing it, used a 835257K9hub kit which that setup still has the fore-and aft slop.

The K9 ending number is matched to a Flo‑Torq III (3) hub kit which is a newer designed hub system mainly made for engines that are fitted with a Command Thrust (Old Big-Foot) gear case housing. The 3 and 4 hub kits are to help lower Clutch Rattle noises at idle speeds.... The Hub they installed should of looked more like this style with the groove/spacing in the center of the hub plastic, https://www.ebay.com.au/sch/i.html?...TRC0.H0.X835257K9.TRS0&_nkw=835257K9&_sacat=0

The link under this quote is directions of how to install most Merc Prop kits which might be worth trying to make a copy and hang it on a wall for all to see....Take note that some Flo-Torq ll propeller hub kits may come with/need a hub bushing too which is part item letter "b" = Hub bushing.

Flo‑Torq III and Flo‑Torq IV Propellers NOTE: The Flo‑Torq lll and lV propellers are designed to have a small amount of free play when installed. This free play allows the propeller to slide back and forth on the drive sleeve adapter (up to 3.17 mm [1/8 in.]) and rotate up to 10 degrees. Flo-Torq lll and lV Propellers Fastened with a Locknut 1. Install the propeller onto the shaft with the supplied components, as shown. If the components supplied with the propeller are different than what is shown, refer to the propeller installation instructions provided with your product or contact your dealer. 2. Tighten the locknut to the specified torque.(55 lb‑ft) 3. Secure the locknut by bending three of the tabs into the grooves in the drive sleeve adapter.

Bear in mind that being the engine has a command thrust gear housing and should the boat owner now notice a new noise then you may want to order and reinstall the K9 (F-T 3) kit for the other engine.

PROPELLER INSTALLATION INSTRUCTIONS - ?

https://www.youtube.com/watch?v=2-lhtReopcI

Let us know and good luck.