1957 SeaKing lower unit "slipped out of gear" at WOT

singer202

Cadet
Joined
May 16, 2014
Messages
24
Hi again. I'm excited to say that with your help I've finally got this Motor up and running and it was going great! After about an hour of motoring around, I went to WOT for about 20 seconds until suddenly it seemed to slip out of gear and the RPMs shot up drastically as the boat slowed. Naturally I cut the throttle down immediately and as it throttled down it seemed to catch again and I was off. After that, it may have been my imagination, but it seemed as though when I throttled it up that it didn't quite have the muscle that it had before, as if it were no quite grabbing. I don't know if this makes much sense but I'm hoping someone can give me some ideas of what may have happened. I'm hoping that maybe its just a matter of adjusting the shift lever but I'm not familiar with how to do that properly. Since I've been posting so much about it, I included a pic of the motor on my boat with the side cowlings removed. Thanks again!
 

nwcove

Admiral
Joined
May 16, 2011
Messages
6,293
did it bang like you hit something or just rev up when you pushed it? from your description tho, it sounds like a spun prop hub. you can check it b removing the prop and marking a line across the backside, put the prop back on and re-create the issue, remove the prop and see if the line you marked on it is no longer lining up.
 

singer202

Cadet
Joined
May 16, 2014
Messages
24
It did not bang or make any unusual sounds. It just suddenly lost thrust and reved up. If it is the prop hub, how is this repaired?
 

max62

Seaman
Joined
May 12, 2014
Messages
51
It did not bang or make any unusual sounds. It just suddenly lost thrust and reved up. If it is the prop hub, how is this repaired?

Typically prop hub isn't repairable. Hub insert is press-fitted and made of rubber or plastic material. The material is meant to be the weakest link in the drive "chain" so if you hit something you don't damage the drive linkage or the entire engine.
 

singer202

Cadet
Joined
May 16, 2014
Messages
24
So does that mean that the fix (assuming that's the problem) is a completely new prop?
 

max62

Seaman
Joined
May 12, 2014
Messages
51
Usually, yes.

Buying a replacement hub and finding the shop (and paying their fee) for repairs may be more expensive than a new prop.

Try and see if yours is an interchangeable hub or just a regular press-fitted type.
 

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
You can rebuild it. IF the prop is in good shape, rebuild. If damaged, replace.
 

singer202

Cadet
Joined
May 16, 2014
Messages
24
Ok High Trim. The prop was definitely spun. I was able to press the old hub out of the prop so now what? Is there somewhere I can order a new hub that is for these old pin drive props or what? I found a complete replacement hub here on iboats, but if I can save some money on just a new hub that would be ideal.
 

singer202

Cadet
Joined
May 16, 2014
Messages
24
With a lot of WD40, a bench press and some patience, I was able to press it myself. Thanks for the info guys!
 
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