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Are the Merc 450s having any issues like prop shaft breakage

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Are the Merc 450s having any issues like prop shaft breakage

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Old 09-12-2021 | 03:41 PM
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Originally Posted by Cash Bar
I ran a 34MTI w 450s about as hard as you can for the last 13 months. Had a bad O2 sensor and bought a $11,000 set of props, but no broken shafts. And loved every minute of it.
I see that your boat is for sale. Whats next?

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Old 09-12-2021 | 04:10 PM
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Boat has been sold. Cat out of the bag story on Speed on the Water (Facebook) getting DCB
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Old 09-12-2021 | 09:46 PM
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Well, damn, I missed that! I love it when somebody sets a goal, works their tail off, and then makes it happen. Congrats to both of them!
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Old 09-13-2021 | 12:07 PM
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In June I broke a prop shaft at the end of the threads with a battery operated impact wrench putting a prop on.....was told by the local merc guy that they would have to run a scan tool on the engine for it to be turned in for warranty.....and the shaft was 6-8 weeks out.....i got lucky and found one and just paid for it, sent the lower to a shop and had them swap out the shaft and got back running in a week....it did not make sense to me to lose the bulk of my season waiting on a part for warranty reasons.....pay attention to torque specs when tightening the prop nut.
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Old 09-13-2021 | 12:42 PM
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Didn't the Cat running for the dam to dam record on LOTO break a prop shaft ? I think they were running 450's
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Old 09-13-2021 | 01:08 PM
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I read that they hit something in the water. Saw video of them changing lower unit and prop was still on the shaft when the boat came out of the water.
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Old 09-14-2021 | 09:39 AM
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Hopefully they were still able to warranty the broken shaft so at least now you'll have a spare.
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Old 11-29-2021 | 03:19 PM
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Anyone have any updates to this thread? I broke one prop shaft this season and warranty covered the shaft and the prop. I'm now hearing motor mounts are failing and Mercury Racing has an update part # for the new motor mount but haven't been able to confirm that.

I'm at around 69 hours on my 450s, who has the most hours on theirs?
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Old 11-30-2021 | 05:50 AM
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Originally Posted by TVMNick
Anyone have any updates to this thread? I broke one prop shaft this season and warranty covered the shaft and the prop. I'm now hearing motor mounts are failing and Mercury Racing has an update part # for the new motor mount but haven't been able to confirm that.

I'm at around 69 hours on my 450s, who has the most hours on theirs?
There’s a Service Bulletin that addresses the motor mounts. It includes relocating a grounding strap that is believed to allow a motor mount bolt to loosen. The other bolts are torqued to a higher spec. I’ve completed at least 20 SBs (mostly quad applications) and only found one mount failure. Most engines that were produced in 2021 have already been corrected. The others need to be addressed. If you own a 450R, supply your serial number(s) to your dealer and have them check if they’re affected.

The most hours I’ve personally seen on 450s is over 2500 on quads (charter boat). Several others are over 1000 hours or very close. The overwhelming majority of those hours are at idle since these are all used for fishing and it’s not hard to log 8-10+ hours each time they go out. Most of our 450 customers have quad setups. We maintain at least 8 different Freeman 47s along the northern Gulf Coast.

Last edited by davidwademarine; 11-30-2021 at 05:56 AM.
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Old 12-03-2021 | 12:00 PM
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Originally Posted by davidwademarine
There’s a Service Bulletin that addresses the motor mounts. It includes relocating a grounding strap that is believed to allow a motor mount bolt to loosen. The other bolts are torqued to a higher spec. I’ve completed at least 20 SBs (mostly quad applications) and only found one mount failure. Most engines that were produced in 2021 have already been corrected. The others need to be addressed. If you own a 450R, supply your serial number(s) to your dealer and have them check if they’re affected.

The most hours I’ve personally seen on 450s is over 2500 on quads (charter boat). Several others are over 1000 hours or very close. The overwhelming majority of those hours are at idle since these are all used for fishing and it’s not hard to log 8-10+ hours each time they go out. Most of our 450 customers have quad setups. We maintain at least 8 different Freeman 47s along the northern Gulf Coast.
Thank you so much for the info! My motors were produced 08/20 so I'm assuming they will need the SB completed. I will schedule maintenance with my shop of choice and get them completed.

Again, much appreciated on the info!
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