Prop shaft very slight wobble

[Crappie Kid]

I hit some rocks in May. I have had the prop fixed, and have bought a new replacement.

There is a very, and I mean small wobble (< 1/8 inch) in the shaft of my Yamaha F80. I do not feel any abnormal vibration or loss of performance.

What should I do (repair/replace shaft) and can I do it myself (mechanically capable).

Thanks

The Kid

[The Kid]

ttt

[Dave in Mpls]

In my opinion, ANY wobble in the shaft is too much.

Sorry, can't help with ease of replacement.

Regards

[FJH1]

I agree, any wobble is too much and will result in the premature destruction of the bearings, seals and lower unit internals. Just my opinion, but I'd get it fixed.

Best Regards,

FJH

[perchjerker]

I agree with Dave and FJ. Actually, 1/8" is quite a bit when you are talking about the close tolerances in a gearcase. Have it fixed before it really breaks your piggy bank!

[Shellback]

I would also think that any wobble is no good. I bent the shaft on my 25 HP Merc and it cost me around $300 to get it replaced. The shaft and seal kit was well over $200. My shop told me that they can be straightened if not bent bad, mine was real bad! If you are looking at the outside of the prop hub and seeing a wobble, it could just be in the casting. Take the prop off and try and clamp a piece of stiff wire to the cav plate so that it is very close to the outside of the end of the shaft. Then rotate the shaft to see if the wobble is actually in the shaft. If it is, I'd get it repaired.

[Crappie Kid]

Can it be straightened out while it is on the the motor?

The Kid

[Tom P]

CK, was your prop aluminum or stainless? Yes, get it fixed ASAP. You could be putting undo stress on your gears if their gear lash tolerances have changed. If you are going to do this yourself, I too would look into the condition of the case where the main brearings for the shaft are pressed into. Hopefully you can get a manual that goes through the gear lashing procedure in detail, if you are going to do the work yourself.

[Tom P]

Just read this post after posting my below post. I would advise against trying to straighten it on the motor. I myself think trying to do shortcuts in that area is penny wise and dollar foolish. Insurance should cover it, I would think?

[Crappie Kid]

The prop was aluminum and was badly damaged (couple chunks missing).

I will get the lower unit repaired.

Did someone say this might be covered (- deductible) by insurance?

Thanks,

The Kid

p.s. I hit rocks in Lake Waubesa South of Madison WI on a very windy day.

[bigfish1965]

Unless you get into a thousand bucks or more, pay for it yourself. Little claims will drive your premiums up and they will get that money back and then some.

[DELTA JUNCTION]

I hit some rocks with my F100 last year and the shaft had a large bow in it. I had to drive back to the landing at about 5 mph. The fact that it was bent didn't surprise me, as the prop was really mangled and it was quite a jolt. I got it fixed for around $700 (including a new prop).

Approximately two weeks ago I hit a submerged stump at a very slow speed. It was definitely a glancing blow and the prop looked undamaged. After looking at it closely, I noticed that there were a couple of subtle bends in it, so I ordered a new prop and sent that one back to be rebuilt. I thought my problems were over, but there was still a slight wobble. To make a long story short, even a glancing blow that barely damaged the prop itself was enough to bend the prop shaft again. I'm wondering if there is a design flaw in that part.

I'm faxing my repair estimate to my insurance company as we speak.

[Crappie Kid]

DELTA JUNCTION,

I am sure the F80 and F100 share the same lower unit.
Let me know what you find out about that shaft. CrappieKid@msn.com.

Thanks,

The Kid

[The Great Guide]

Get the shaft replaced befor you use the motor again. The torque on the prop will rip out your shifting linkage. The seal will fail and you will need more than a shaft. It will happen on the second day of your week long vacation. Also, check and make sure your skag is staight. If you had an aluminum prop and still bent the shaft you hit those rock with a good deal of force. You could have also knocked the shifting linkage out of adjustment.

I just had my shaft replaced on my VMAX 150 for $450 which included the shaft, seal, skag and stainless prop repair. I was going less than 10MPH, but there is no give to the stainless. Go ahead and use your insurance. That is why you pay for it. Your rates will not go up unless you are a real hazard and have lots of claims.

TGG

[ChuckD]

There should be no play whatsoever.
Here's my predicament:
'99 Johnson 115 - accidently backed into underwater cement brickades at a launch site. It was the slightest tap on the motor, but bent my aluminum prop...it was fixable.

I didn't think that would have done any internal damage, but I was wrong. I broke a tooth on a gear in the lower unit which metal shavings ruined a seal in the lower unit = oil slick on water a year later!

I found metal in my lower unit lube (after 3 lube changes) and knew something was wrong, so I brought it to the mechanic to fix the seal and inspect the cause for the shavings.

Bad news! That one hit to my motor at the launch caused $1550 in damage. $1150 in parts and rest labor to fix. It bent the driveshaft over the recommended amount of "give", prop shaft, broke gears, clutch dog, water pump, seals, etc...etc...etc.... Basically have to get a whole new lower unit!

There was no way I could tell there was a difference in the performance of my motor. Nothing, but the shavings and the seal leak!
I don't even know if my insurance will cover this damage because it happened a year ago, replaced the prop since, never knew there was a problem....never ever hit any other objects with this motor....all I have is 3 witnesses who saw what happened.

I would drain your lube and see if you have any evidence of damage like mine. Fix the problem before it really gets bad.