Vibration after hitting log

[aaroncat]

Hey folks,

A couple of days ago we hit a pretty big log at surf speeds. Immediately after and ever since we have been experiencing vibrations at all speeds (especially noticeable during holeshot). No performance issues and haven't been able to identify any dings in the prop and the exposed section of the drive shaft looks fine. I'm going to take it in to the shop soon but wondered if anyone had ideas on what it might be.

Cheers,
Aaron

[C.Hern5972]

Probably bent prop.

I've done it before. Bent strut, shaft. Sucks for sure. Didn't know it was bent until they unbolted transmission and it wouldn't line back up

[wolfeman131]

Stop running that thing right now! You're taking a big risk of tearing more up and racking up some serious repair bills.

[deafgoose]

It happened to me while surfing also.

The prop looked perfect but when I measured the distance between each blade, one of them was off.

It does not take much to knock these props off balance.

[eblom]

I did the same thing yesterday while surfing... Hoping its only the prop!

[aaroncat]

Thanks guys. The boat is out of the water and I kicked off an insurance claim just in case.

[deafgoose]

i kicked off an insurance claim just in case.

big mistake

[aaroncat]

big mistake
Can you elaborate?

[deafgoose]

Can you elaborate?

From the symptoms you are describing, it sounds pretty minor.

A prop rebuild will only cost you a few hundred bucks. I am not sure about your deductible but it may even be more than a rebuild.

I would have got a full estimate before making the decision to do an insurance claim.

One day, you will hit something big. That is when you want to make a claim.

[aaroncat]

My plan was/is to alert my insurance company, get the boat to the shop, find out the damage and then either bail or proceed with the claim. From my initial conversation with the insurance rep this is a reasonable approach. Right?

[Boonejeepin]

I work in the auto insurance industry. One factor on rates is claim frequency but claim payout also matters.

Your claim needs to be reported timely but a few days after the incident is timely in my eyes.

I hope the damage is confined to the prop. It is a bad feeling to hit something.

[wolfeman131]

we have to have another insurance guy around here, don't we?

I know that when I called Liberty Mutual to look at my roof after a hail storm a few years back, it opened a claim and my rates went up even though they found no damage and made no repairs or restitution.

Interesting part of that was almost every house in the neighborhood and on our street was found to have hail damage and got new, free (less deductable) roofs put on.

[aaroncat]

Ok, so the boat is in the shop right now and the mechanic said that he couldn't find any signs of damage. He is 99% sure the vibration is caused by loose coupler bolts but both him and I were confused since it seems impossible that the impact with the log would cause coupler bolts to loosen. This vibration instantly appeared after hitting the log :confused:

[wolfeman131]

Easy thing to do is throw a new/spare prop on and see if vibration is still there.

[eblom]

I put my spare (stock) on and there was no vibration... A slight ringing from the prop at 2200 RPMs and the OJ growl but no vibration. Then went to check the alignment and found 2 loose coupler bolts and my gap seemed to follow around as the prop was rotated 180 degrees... Not good... I dropped it off at the shop this morning to have them check it out... They will either align the drive shaft or do that and straighten the shaft... and they promised to have it back by the weekend...

[wolfeman131]

Good luck!

[jpetty3023]

Fingers crossed


Sent from my home phone..

[eblom]

Thanks guys!

[aaroncat]

I retrieved the boat from the shop yesterday (after they took care of the loose coupler bolts for $200 :(). Nothing has changed, same vibration under power.

Starting to think that the loose coupler bolts should have been picked up prior to now. The shop had my boat three times when it had 100.9 hours. First, for the 100 hr service, then the winterization and then dewinterization/spring service. I have 111 hours on the boat now! Could these bolts have come loose in 10 hours of usage?

[mnpracing]

stupid question, but did they water test it and said everything checked out?

[aaroncat]

No water test. The mechanic claimed he was 99% sure the coupler bolts were causing the vibration.

[mnpracing]

No water test. The mechanic claimed he was 99% sure the coupler bolts were causing the vibration.

man that sucks. it's frustrating to have to take the boat in in the first place, but then to continue to have the issue....

[eblom]

Do you have a spare prop? Put it on and see if that was it... The prop can look perfect to the naked eye (mine did) but if the log slightly bent the pitch of the blade(s) your boat would vibrate and possibly vibrate your coupler bolts loose. My bent prop looked fine but my boat vibrated like hell until I but on my spare... YOu could also dbl check your shaft alignment... This will also tell you if you have a slightly bent shaft... Good Luck!

[jpetty3023]

No water test. The mechanic claimed he was 99% sure the coupler bolts were causing the vibration.

Man you gotta hate when they wrong 1% of the time


Sent from my home phone..

[wolfeman131]

I think the coupler bolts are supposed to be part of that 100 hr service and they should eat that $200 b/c I don't think they should have come loose after 10 hrs.

[squeeg333]

They shouldn't have come loos after 10 hours of use, unless they've been run up and down the bolts a few times. They are just nylocks, and that nylon wears down after a while. When I got my boat, it had about 100 hours on it, and when I went to winterize it the first time, found they were all loose. I highly doubt that loose coupler bolts are causing any sort of vibration - they sure didn't on mine!

I would say it's either the prop, your alignment, or the prop shaft or all of the above. Have they checked all these various parts when you took it in? Or rather, what have they checked??

[bzubke1]

Sorry to hijack but where are these coupler bolts, I'd like to check mine.

[motosno963]

Sorry to hijack but where are these coupler bolts, I'd like to check mine.second..i hit a log about as thick as a football when i was pulling my buddy on the wakeboard..i took her home and i saw that i finished off my prop(w/ a little vibration ) now its time to update to an ACME

[DOCDRS]

Sorry to hijack but where are these coupler bolts, I'd like to check mine.

Coupler bolts are under the vdrive, where the vdrive connects to the drive shaft.

[DOCDRS]

I retrieved the boat from the shop yesterday (after they took care of the loose coupler bolts for $200 :(). Nothing has changed, same vibration under power.

Starting to think that the loose coupler bolts should have been picked up prior to now. The shop had my boat three times when it had 100.9 hours. First, for the 100 hr service, then the winterization and then dewinterization/spring service. I have 111 hours on the boat now! Could these bolts have come loose in 10 hours of usage?

The only way to know if your alignment is correct is to check it yourself. I hate to say this but even mechanics who know how to do this properly are satisfied with more than acceptable tolerances. Plus I really believe most mechanics don't comprehend the ideal of how to properly align an engine an transmission. I have had disagreements with some whom I know are indmar certified and even thou I trust them with the engine I don't with the alignment. That being said even a misaligned engine and bent shaft of .005 will not show any vibration on acceleration, wot and power turns. Coupler bolts should not come loose in 10 hours and I do believe alignment is part of the 100 hr service and to do that you must loosen the coupler bolts!!!!

[eblom]

I got the boat and prop back today... The shaft wasnt bent but the alignment was the worst they have ever seen... They said it looked like someone had pulled the engine and just slapped it back in... Anyway I am aligned and back on the water this weekend!

[kaneboats]

Please keep us posted on what you find out.

[rdlangston13]

I got mine aligned in the offseason and they said it was really bad. My right front motor mount rubber bushing part is splitting so I reckon I'll be in to get that fixed soon and another alignment


Sent from my iPhone newtys droid killer using Tapatalk

[aaroncat]

The shop took it out on the lake with a spare prop and sure enough it was the prop causing the issues. Prop is off to get repaired with a 1 week turn around.

After this ordeal I will have to get a spare prop and learn how to remove and install it.

Thanks everyone!

[aaroncat]

Did a little bit of digging around the forums. Looks like it is pretty easy to swap out a prop (using either the puller or heat).

How does one go about getting the prop locked back in to place when re-installing? I read something here along the lines that it isn't really correctly on the shaft until you put it in gear (in the water) and it snaps into position. Is that accurate?

[moombahighrider]

Mine has a key that fits in the slot that is in both the shaft and prop. When installing the prop you just line the prop up correctly, slide it on and tighten the nut, install cotter pin, done.

[eblom]

If you mark the shaft with a sharpie just tighten to your mark... Or I think its 50 lbs on a torque wrench... A torch works great to remove it just be careful you dont melt the nylock nut... I have an old one I put on... Its best to leave the nut on a few turns bc the prop can pop off and the nut will keep it on the shaft...

[Boonejeepin]

If you mark the shaft with a sharpie just tighten to your mark... Or I think its 50 lbs on a torque wrench... A torch works great to remove it just be careful you dont melt the nylock nut... I have an old one I put on... Its best to leave the nut on a few turns bc the prop can pop off and the nut will keep it on the shaft...

+1

You want the prop fully seated when the key is in place. Fully seat the prop w/o the key and mark the spot with a sharpie. Insert the key, install the prop and adjust if needed to get the prop seated to the same depth on the shaft (your sharpie mark). Tighten nut.

[DOCDRS]

Prop is 30-35 ft lbs not 50. And you only heat the front of the prop as this is where it binds on the shaft (tapered shaft)...there should be no concern for the nylock as the heat is applied to the prop not the shaft and opposite side as the nut.

[eblom]

Thanks for the correction... My memory failed me on that one... And I dont know how I softened that nut... But I did lol