Best way to check prop shaft after a collision

[twitch]

My partner hit not one but two rock piles yesterday, but shut the engine down and of course there CB is a big. Hunk of the skew gone and the prop is junk .250 Yamaha what is the best way to see if the prop shaft is bent and if he needs it to be replaced.

[RonCat]

Sounds like a certified mechanic is in his future. I hit something and had enough hours in the seat to tell something was wrong, but it wasn’t visible by any means. Am certain there is a tool to measure/check. Prop shaft and prop were covered by insurance.

[mark482vs]

One time I hit a rock pile and the shaft look straight when you turned prop by hand with a dial indicator on it. dealer said we will just put new one in. I said can we xray for cracks, doesnt pay he said, and ins. will pay now but not later if it fails. Friend did just that, and when it broke the shaft broke first trip put next spring he had to pay out of pocket

[Bill Reynolds]

I still have my Machinest tools so I have checked my prop shaft a couple times after tearing up a prop but it was OK each time. It has to be a really bad collusion to bend the prop shaft because the rubber hub takes most of the shock.
As stated, unless you have a dial indicator, it will have to go the shop.

[Bass Cat Boats]

Prop shafts have a centering hole when they are cut. Spinning it will show the out of round on the rotation. It’s simple to see and you can mount and hover a flexible ball shaft machinist arm over the center if you’re really worried. Though that’s not necessary as you should see it easily.

Also spin your prop occasionally, if there’s water inside they will free spin, while thicker liquids like gear oil have resistance. it won’t show a milk shake combo unless it’s really mostly water, but we’ve found dozens with water by spinning the shaft.

[mactlman]

likely needs a lower unit now!!

[MichAngler]

When I took mine in to be checked they had a nicer version of one of these

https://www.amazon.com/Neoteck-Indic...6209066&sr=8-9

[tj]

After I ran over a log in 2011 (~ 45mph maybe), had new boat dealer where I got yearly maintenance/batteries check out the 1997 Mercury 175 EFI & prop shaft (was OK), I asked boat dealer to send 1997 A45 prop to prop shop to get checked (prop shop - was OK), dropped off Champ at Truman Fiberglass Repair (no longer in business now, pad needed repaired $1017.39 bill). Didn't use insurance policy for this.

[Bob G.]

I use a dial indicator with a magnetic base and adjustable arms from igaging.com. Obviously the magnet doesn’t stick to the cavitation plate, I use an adjustable clamp. I check the prop shaft when I winterize my boat motor after I take the prop off. I record the value on the winterizing sheet for that year. Yea I know, OCD.

[BroWhoop]

Prop shafts have a centering hole when they are cut. Spinning it will show the out of round on the rotation. It’s simple to see and you can mount and hover a flexible ball shaft machinist arm over the center if you’re really worried. Though that’s not necessary as you should see it easily.

Also spin your prop occasionally, if there’s water inside they will free spin, while thicker liquids like gear oil have resistance. it won’t show a milk shake combo unless it’s really mostly water, but we’ve found dozens with water by spinning the shaft.

This^ You can see the very small movements, as much .0010", with good light and vision.

[Schooler]

If it was a sho then it is bent.

[Lightning 6]

Run out gauge.

[BlackGrouper]

I clamp a piece of wire like a coat hanger to the skeg with vise grips/quick clamp. Bend it around and center it to the divot at the end of the propshaft. Spin the shaft, and see if there's any runout.

[Thamelau]

The most accurate and best way would be to use a dial indicator. Idk if that level of accuracy is required, but it would be the most accurate result and give a true runout number.

[mark482vs]

its just about shaft bend it could be cracked nd twist off later. at your expense, let ins. pay now because they wont pay next year . they will claim it just part failure