# Spun Prop without any apparent reason



## Wolthoff (Feb 7, 2014)

I’m running a brand new Baumann Bullet 12 pitch 3 blade on my brand new Tohatsu MFS60 and HB Pro tunnel. The prop was initially a 14 pitch, but I sent it back to Baumann to bring the pitch down for more RPM. I was only getting 5200 to 5600 WOT trimmed out with the 14 pitch. I got the prop back on Thursday and ran it yesterday. We were running for at least 20 minutes WOT, and then my RPM jumped to 6200 RPM and the prop just spun. We were able to limp back home at 3000 RPM, but anything over 4000 we’d spin out. There’s no other apparent damage to the prop and we didn’t hit anything that I’m aware of. Any ideas or thoughts on what would cause this? Is it possible that the hub was just faulty or should I be concerned about something else? Thanks


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## Smackdaddy53 (Dec 31, 2012)

Call Louie Baumann


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## devrep (Feb 22, 2009)

pretty sure they use heat to re-pitch a prop.


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## Smackdaddy53 (Dec 31, 2012)

devrep said:


> pretty sure they use heat to re-pitch a prop.


Louie and his family have been making props for ships and boats longer than we’ve been alive. Not saying they did not somehow cause the issue but it’s highly unlikely, especially when they tweaked one of their own props.
It could have been just from hitting a stump and then it started slipping later when some force was applied or maybe a bad hub press job. It’s all speculation until he sends the prop back for inspection by the shop that made it. Fishing rods sometimes break several trips later from a slight fracture, same thing with a slipping prop hub.


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## Bonesonthebrain (Jan 2, 2020)

Did they rework the prop, or replace the prop with a lower pitch? If reworked it could have been heated and if they left the hub in the prop it could have been compromised. Or if the hub was removed and reinstalled it could have for whatever reason gotten damaged. Sh*t happens.


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## Smackdaddy53 (Dec 31, 2012)

Bonesonthebrain said:


> Did they rework the prop, or replace the prop with a lower pitch? If reworked it could have been heated and if they left the hub in the prop it could have been compromised. Or if the hub was removed and reinstalled it could have for whatever reason gotten damaged. Sh*t happens.


Did you read the original post or my post?


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## jay.bush1434 (Dec 27, 2014)

Pull the prop and check the insert. Baumann uses a metal hub insert and I've seen that insert shear the hub engagement tabs. Easy to replace. Call Baumann props and they can get you taken care of. This just happened to a buddy the other day.


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## Sublime (Oct 9, 2015)

jay.bush1434 said:


> Pull the prop and check the insert. Baumann uses a metal hub insert and I've seen that insert shear the hub engagement tabs. Easy to replace. Call Baumann props and they can get you taken care of. This just happened to a buddy the other day.


Was that the guy you were towing in? Wondered what happened.


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## jay.bush1434 (Dec 27, 2014)

Sublime said:


> Was that the guy you were towing in? Wondered what happened.


Yes. They said it ran fine on the way out. Went to move to a different spot and it revved up and made a rattling/clanking sound but no propulsion.


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## scissorhands (Apr 8, 2012)

Wolthoff said:


> I’m running a brand new Baumann Bullet 12 pitch 3 blade on my brand new Tohatsu MFS60 and HB Pro tunnel. The prop was initially a 14 pitch, but I sent it back to Baumann to bring the pitch down for more RPM. I was only getting 5200 to 5600 WOT trimmed out with the 14 pitch. I got the prop back on Thursday and ran it yesterday. We were running for at least 20 minutes WOT, and then my RPM jumped to 6200 RPM and the prop just spun. We were able to limp back home at 3000 RPM, but anything over 4000 we’d spin out. There’s no other apparent damage to the prop and we didn’t hit anything that I’m aware of. Any ideas or thoughts on what would cause this? Is it possible that the hub was just faulty or should I be concerned about something else? Thanks


Curious how yours is set up. JP, motor height? I run the same prop in a 14, just sent it in to get reworked because it wore out.


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## Wolthoff (Feb 7, 2014)

scissorhands said:


> Curious how yours is set up. JP, motor height? I run the same prop in a 14, just sent it in to get reworked because it wore out.


I’ve got it mounted as high as it can be on the Atlas Micro. I quickly found out that I don’t need to jack it up much at all.


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## scissorhands (Apr 8, 2012)

Wolthoff said:


> I’ve got it mounted as high as it can be on the Atlas Micro. I quickly found out that I don’t need to jack it up much at all.


Roger that, Just curious.


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