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Posts: 1023
| I just bought a lightly used 75 hp optimax (2007). Lower unit and motor are clean as a whistle.
I noticed today that the prop can be wiggled quite a bit at the front end (where it meets the lower unit). The prop shaft is straight, snug and not wiggling and the lower unit is not leaking water or anything. (I haven't taken the prop off (cause I am not so handy and I wanted to check here first). Is this typical of these props/motors or should I investigate further???? Seems like there is a gap in the support for the prop near the front. Is there a sleeve missing or broken in there maybe?
Thanks for your help
Landry |
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Posts: 1887
Location: syracuse indiana | what kind of prop is on it, that might help us in fuguring out where to start...bill |
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Posts: 1023
| Thanks Bill.
It is just the standard factory aluminum prop - don't know pitch... Engine RPM's, speed and hole shot are all good. I just read that these motors have a hub assembly (flo-torq III) that sometimes leads to lateral prop movement on the shaft - it may not be a problem???? Anyone know anything about these hub assemblies and this lateral movement issue!!! Have you seen this on your optis? |
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Posts: 3508
Location: Elk River, Minnesota | Hiya,
I would pull the prop off.... Here is what I am betting: There is a thrust washer that goes between the prop and the lower unit. Now...I'm the stock thrust washer from Mercury would fit flush to the inside of the prop with little to no wiggle room.
I just purchased a prop that takes the XHS hub system (just like merc's torque flo system) and the thrust washer that came with that did not fit flush against the inside of the prop. I am guessing since Michigan builds them that way, they must be ok, but that bothered me too. I just put my stock thrust washer on, and it fit right. I had to add a washer by my castle nut, but no big deal there to me.
Steve |
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Posts: 272
| I'll second what VMS said.
I forgot if it was a michigan wheel or turning point (maybe they're the same)......but I borrowed a buddie's prop to try on my motor and that thing wobbled around like my 4-month-old boy trying to hold his head up. I mean it would move 1/8th of an inch.
Ran it at idle speeds, but couldn't bring myself to take it up on plane like that, didn't really want to go running around looking for a new thrust washer.....so I put my old one back on and called it a day.
Stopped in at a couple of prop shops around green bay, and even called turning point. All said it should be fine, some mentioned something about a prop nut or a washer. I'm not sure that was the problem, but it might have been.
I just couldn't justify running a non-snug prop at 6k rpm. Something about that didn't seem smart. |
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Posts: 247
Location: Uxbridge Ontario | I think all you need is a new bushing kit. I had a buddy service my boat in the fall and that was something he looked at my engine for (I have a 2007 75hp Opti too). He said at times the bushing wears out and they are a simple fix. |
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Posts: 1023
| Thanks for all of your help everyone. I will take it off and inspect. Do I need to torque the nut to the specified rating or just put it back on and snug it? Is a torque wrench necessary/needed???
Landry |
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| I have a brand new Optimax 90 hp with 1/8 inch play in prop. I looked in the manual that came with the motor . It says that the prop is suppose to have 1/16-1/8 play in it. |
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Posts: 1023
| That seems odd doesn't it - but I fully believe you. Mine moves laterally 1/8" when I push it sideways where it meets the lower unit (it moves at this end only) - is that how yours moves? Thanks so much!!!! I have no manual for my motor as the guy I bought the boat from lost it.
Landry |
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Posts: 247
Location: Uxbridge Ontario | Landry,
I just brought my boat home from storage. I'll check mine out in a few minutes
Are you from Southern Ontario? The name sounds fermilure... Humminbird transducer switch sale? |
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Posts: 1023
| yes - I am - are you the guy I sold that to - Ryan I think???
Landry |
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Posts: 247
Location: Uxbridge Ontario | Landry - 5/4/2010 3:20 AM
yes - I am - are you the guy I sold that to - Ryan I think???
Landry
Yep, that's me.
As for the prop, I have virtually no play. Virtually as in 1/16" movement pushing it pretty good. Again, this is on a 2007 Optimax 75hp with close to 60hrs on it... I would guess. Prop is the standard 19P aluminum Blackmax that came with the engine.
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Posts: 14
| I noticed this problem myself not too long ago, but I actually forgot about it until I read this thread. I just looked in my manual for a 2008 115hp opti and it says" NOTE: the flo-torque lll propeller drive hubs 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 rear thrust hub [up to 3.17mm (1/8 in.)] and rotate up to 10 degrees." |
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Posts: 1023
| Thank you everyone. I will just leave it be. I am sure it is fine as it is the original prop and has no nicks and only 20 hrs on the motor.
Landry |
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| i have a similar question.. i have a mirage prop, don't know pitch. but mine is also loose, when i bolt on the prop it is tighten but the prop still is loose, you can pull on it and push in on it still. anyone have an answer to this? |
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Posts: 1023
| Forward and back play is apparantly okay on the optimax props according to my local marine tech. It seems to be snugger since they looked at it though. |
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Posts: 1096
Location: Hayward, WI | That motor has a flo-torqu 111 hub and that is normal. |
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