Broke a prop - limped back to ramp - Should I get the engine checked out?

[mstan55]

Hello everybody-

I have a 1999 50 HP Johnson 2 stroke.

I broke off one blade of my 3 blade prop last time I was out. I was almost on plane when I heard the crack. I was in 6 feet of water, but must have hit something I guess. Anyway, I heard the crack and pulled back on the throttle to idle. Then I did try to give it some gas for about 5 seconds, and noticed the bad vibration of the outboard. Next I inspected the prop, and sure enough an entire blade was gone. I then limped back to the ramp at idle speed, about 1 mile away (lucky).

Do you think I should have the engine checked out before I take the boat out again? I hoped to minimize any damage by limping back to the ramp at idle, but I'm nervous about that and the brief period (no more than 5 seconds) where I tried the throttle after the prop was broken.

Thanks for reading!

 

[wilde1j]

Re: Broke a prop - limped back to ramp - Should I get the engine checked out?

Check the prop shaft for being bent. Use a dial indicator or very carefully eyeball it as it is slowly rotated in neutral. You're looking for a small amount of bend (I would want jno more than 0.002" max., which will be very hard to see w/o a dial indicator.) Also, carefully inspect the whole lower unit for cracks and dents.

 

[mstan55]

Re: Broke a prop - limped back to ramp - Should I get the engine checked out?

Thanks very much for the reply wilde1j.

I did a visual check on the prop shaft today as you described, and did not notice any bend when I turned the shaft slowly by hand. I've never used a dial indicator before, so I'm quickly out of my league there. Do you think if I called around to machine shops and took the boat to them that they would check this for a reasonable cost?

I also did a careful check of the lower unit, and did not see any cracks or dents there. Got lucky on that I guess.

Thanks again for your time.

 

[wilde1j]

Re: Broke a prop - limped back to ramp - Should I get the engine checked out?

Any decent machine shop shop be able to check the shaft runout in a few minutes. Should be within a few 0.001"'s of straight to be OK. If it's bent, a machine shop can straighten, but you or someone would have to pull the shaft.

 

[mstan55]

Re: Broke a prop - limped back to ramp - Should I get the engine checked out?

10-4 capt. I'm going to try a few shops around here and see if they will help me out. Thanks again. I have a shop manual for my engine, and have been reading up on pulling the shaft. I probably wouldn't try this on my own, but I know of a guy that would probably do it for a fee of course.

Thanks again!