Vibration ?

I put the 91 Sport in the lake today for the first time,   It didn't sink, and she ran great.    The only problem I noticed was that it had a slight vibration to it.

At slow Idle speed you couldn't feel it, but when you got on the gas you could feel the vibration.

   The prop doesn't look that bad but it does have some nicks in it.    Could that be the source   ?
    The drive shaft looks good but is there a sure way to check it without taking it out of the boat ?   
      Or is there something else I need to look at ?     
   One of the fins have been replaced.   Looks like a square ended fin from another type inboard ski boat.    Surely that would'nt cause the vibration would it ? It was put on as the front fin.


   Thanks

   

Heres a pic of the Prop,   It looks like I might need to start there right ?

I've only got $3500 in the boat so far, So a Prop wouldn't hurt that bad, or a shaft either if needed.   This is the boat I posted about last summer that had been sitting on the side of the road for a 1yr. The paint job and the hole in the keel was making people " RUN " from it.      I bought the boat for $3K, $500 for the fixed hole. I did order some hydro-turf for the swim deck that was another 80bucks,   Changed the oil and put a new fuel/water filter on it. And got the " Nautique" stickers.    Runs like a champ except for the slight Vibration when on the throttle.   The boat will absolutely fly.     

with that prop on i bet the wife sits on the engine box alot underway...

I turned the prop around a few times and it seems to have the same feel all the way around. Its not in a bind.

   where do I start with the prop, just get a new one or have this one redone ?   All the blades have the same little wave in the edge.

   Thanks

Phil, Also keep in mind that all hulls will set up harmonics at certain speeds/RPM's and will "buzz". I however feel that after looking at the pictures of the prop that it is the major problem. Do check the alignment when you get a chance. It's not a bad idea to do it every year.

#1 choice would be Eric Johnson @ OJ Popellers
Phone # 1-800-359-9730
Tell him the Boat Dr. sent you....75.00 plus shipping
#2 General Propeller ,Larry or Joel
Phone #1-941-748-1528
Same deal mention the Boat dr for a discount

   The Boat dr

I bought a prop from Delta and they were really nice. My order went thru without any problem. By the look of those tall trees I don't think you are in Texas. Otherwise I would suggest B&B Propeller Service. They have done several fixes for me and they charge me very well. Actually the last prop I took to him it has a little dent on one of the leaf and he didn't charge me. I would try what Peter or doc are suggesting.

I don't know if your vibration was caused by having a loose prop but by the look of your prop I would definetly have it straigthen and balance. I have seen similar dents that causes vibration. A loose prop I bet it can caused vibration but I don't know how bad. But with the dent on your prop and loose I bet it would augment the behavior. Also, I read in another thread that when installing a new prop to use lapping compund. This will bore the prop insert slightly so you would have a perfect contact between the shaft and the prop. Next time you take it out it won't be as easy. I know yours has been installed in there for a while so I don't know if you would gain any major benefit but it won't hurt doing. I don't have any washer on mine so I don't know if you need it or not.

If you have a 351 with 1:23 transmission I saw another forum that this size was one of the factory size. I don't know if that was for a SSN like yours. The best advice is to call ACME and talk to them. Maybe is time for you to buy a nice prop. You won't regret. Maybe an ACME 470 or a 1442 (if engine mods) would be appropriate. Call ACME and they would tell you. Get a new one and fix that one and leave it as a spare one.

Phil, The prop not seated on the taper was most likely the vibration but do send the prop in for a tune up as long as it's off.

The prop nut, in theory doesn't hold the prop on. It is the taper in the prop and on the shaft. The nut simply pushes the prop on and seats this taper. Once the prop is tight, it is common to back off the nut so the cotter pin will go in the shaft. The nut will act as a just in case safety if the taper doesn't hold and when put in reverse you won't loose the prop. Lapping the taper is recommended by the prop manufacturers but not done very often but since you prop has been run loose, it may not be a bad idea. When you send the prop in you will want to mention it's been run loose. They can check the taper and ream if needed.

Washer not required.

cook, post a new thread regarding what prop you should purchase, just saying the size sounds a little funny to me and by all means buy from delta, on the post put all the info and someone here will get that boat dialed in with the correct prop if it isnt already.
that prop you have took a good hit and may have bent the shaft a bit, also may have a bend in the strut to.
btw, good deal on the tub