# That freaking hurt



## knot_trying (Oct 28, 2020)

Hit a rock with the prop on my Tohatsu 20 and broke the driveshaft.










So guess where the missing piece was...










Major disassembly to separate the powerhead from the drive shaft housing and then had to start drilling it out. Fortunately didn't have to drill too deep before it finally dislodged.

Wondering if I can put the powerhead back on and reuse the old oil pan gasket. Seems intact.

Oh - also bent 3 teeth on the bevel gear.

Only a small dent in the aluminum prop but it was pretty close to the hub so figure that's why all the damage to the powertrain.

I need a jet!


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## devrep (Feb 22, 2009)

so you're going to do all that work and skimp on a gasket? if its backordered like everything else it's probably not that hard to make one. if you absolutely have to reuse it put high temp gasket maker on both sides.


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## Loogie (Jul 24, 2019)

Never re-use a gasket, not a good plan, from an engineering standpoint, that gasket has done its job, dont tempt fate and put that back on. The reason gaskets work is due to compression , all gaskets have a compression design, once its been squeezed and compressed, it will not perform correctly if used again. Just an engineer squirming at the thought of you using that gasket again


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## DuckNut (Apr 3, 2009)

If you super glue the shaft back together, you can reuse that too.


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## eightwt (May 11, 2017)

Not a mechanic, but even I know not to reuse a gasket. Of course, i would have been calling my mechanic, and not even think about repairing it myself. Good luck.


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## permitchaser (Aug 26, 2013)

So are you doing all the work yourself.


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## Reed Wilson (Aug 9, 2020)

knot_trying said:


> Hit a rock with the prop on my Tohatsu 20 and broke the driveshaft.
> 
> View attachment 180956
> 
> ...


What does the prop look like


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## DuckNut (Apr 3, 2009)

Reed Wilson said:


> What does the prop look like


It'll buff out.


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## MartinK (May 29, 2014)

I'm really surprised that it would have twisted that shaft right off... I would have expected the rubber bushing in the prop to have gone way before the shaft.


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## loganlogan (May 8, 2020)

Loogie said:


> Never re-use a gasket, not a good plan, from an engineering standpoint, that gasket has done its job, dont tempt fate and put that back on. The reason gaskets work is due to compression , all gaskets have a compression design, once its been squeezed and compressed, it will not perform correctly if used again. Just an engineer squirming at the thought of you using that gasket again


In shop class, we used manilla envelopes. Line it up on the housing and use a ball peen hammer to tap/tear the edges off. Does that make an engineer squim too? Lol.


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## lemaymiami (Feb 9, 2007)

I was taught years and years ago how to "beat out" a gasket when a new one wasn't available and it's do-able - but a new one is always preferred. I was taught to use the peen end of a ball peen hammer... Look at the old gasket to see what it was made of (thickness of the material, etc.) and you just might succeed. All those years ago, my Dad would routinely tap out a water pump gasket or other gasket needed for a non-high temp installation - and made a point of showing me how it was done. He actually had to keep construction equipment running in the jungles of both South America and Africa as a work supervisor building air strips for Pan Am - before WWII... In that world you either made do (field expedient) - or did without... 

This isn't the first time I've heard of a drive shaft failure on one of those nice lightweight imported motors.... If any part in your lower unit has failed - replace every moving part with new - without exception since the slightest distortion on a gear, shaft, bearing, seal... will definitely show up in use.... Be a shame to leave anything in that drive train that should have been replaced and wasn't..... 

Good luck, post up what you decide to do, and "Aren't boats fun?"


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## DuckNut (Apr 3, 2009)

MartinK said:


> I'm really surprised that it would have twisted that shaft right off... I would have expected the rubber bushing in the prop to have gone way before the shaft.


Not all props are made with a rubber hub. Probably the minority.


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## knot_trying (Oct 28, 2020)

I'm getting a new gasket - would hate to have a perpetual slow oil leak around the pan.

The prop was an aluminum solas 4 blade. I can see a rubber insert in the hub but obviously not enough of a cushion.

Until I get a jet wondering about either one of those prop guards or else maybe trying a piranah propeller. Better to sacrifice a blade or two for not having to do that repair again.


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## DBStoots (Jul 9, 2011)

knot_trying said:


> I'm getting a new gasket - would hate to have a perpetual slow oil leak around the pan.
> 
> The prop was an aluminum solas 4 blade. I can see a rubber insert in the hub but obviously not enough of a cushion.
> 
> Until I get a jet wondering about either one of those prop guards or else maybe trying a piranah propeller. Better to sacrifice a blade or two for not having to do that repair again.


Curious how fast you were running when you hit the structure?


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## Loogie (Jul 24, 2019)

loganlogan said:


> In shop class, we used manilla envelopes. Line it up on the housing and use a ball peen hammer to tap/tear the edges off. Does that make an engineer squim too? Lol.


LOL, it sure does!!


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## Gogittum (May 24, 2020)

loganlogan said:


> In shop class, we used manilla envelopes. Line it up on the housing and use a ball peen hammer to tap/tear the edges off. Does that make an engineer squim too? Lol.


Corn Flakes boxes work great for that and peen nicely.

Out in the Idaho woods one day around ~1980, I came across an old Drag Saw that had been abandoned there, prob'ly in the 1920s. Took it apart to see if I could get it going and it had a strip of an old Corn Flakes box as a shim in the big end of the connecting rod. It was well pounded, so apparently worked. It was a single cylinder 2 stroke motor. Never did get that thing going.


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## finbully (Jan 26, 2013)

I wonder about bearings too as Capt. Bob says. I would check run-out with a new shaft installed before buttoning it up. I work in power generation and we would never put in a new or reworked shaft without checking run-out. Vibration in the power train is not your friend!


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