vibration

the ding in the prop will hurt your speed a little, but I would say that the carb is why you lost the speed most likely it's a smaller carb or jetted differenty, that's assuming you exchanged it and didn't rebuild the one you had. If the shaft is orginal then you need to replace it. I believe they should be replaced after 500 hrs most people thing thay are good for ever and thats not true. Another thought would be that the cable could be adjusted differently than it was and you are not opening up the carb all of the way. I always did like the century inboards they seem to hold up well and and have a style that never goes out of date.

79 the carb is orignial rebiult by an automechanic with 30+ years experience. I now just enough to get yself into trouble! I set the air fuel adj screws to 1.5 and 1.75 turns out with a dwell meter and still lack of mph are there internal adjustments that I'm overlooking?

[QUOTE=79nautique] If the shaft is orginal then you need to replace it. I believe they should be replaced after 500 hrs most people thing thay are good for ever and thats not true.


Ya Right! Good advise. Change out a prop shaft that has nothing wrong with it. If your shaft is straight there is no need to change it out whether it's original or not. Don't listen to that crap. Bad advise.

That's your opinion. Go try to sell that crap to someone else.
Ya, I understand stress. Especially when you have rock strikes. Maybe you should tear your engine down every 600 hours because it vibrates too. Hey, maybe the vibration causes stress... Maybe you should scrap the whole running gear then. Ya, right!

That was bad advise. Don't even try to play it off on me. Poor, poor advise.
If the prop is dinged then for starters he should send the prop out and get it reworked or get a new one if he would like to upgrade. Curtis Prop can repair them for about $90.00 and check the cupping as well, which may take care of his problem. Chances are that if the shaft is bent it's going to get worse with vibration as speed/engine rpm increases.   But first deal with the prop as it could have a blade that's been cupped from a prior impact. Just eyeing up the prop isn't good enough. While the prop is off you can set up a dial indicator mid-shaft to check for bends while rotating the shaft in nuetral, and also set it up at the tapered and as well when the prop is off. .001-.002 wobble is well within tolerance. Also checking the strut bearing for looseness. A loose support bearing will allow a prop thats been dinged to wobble as it rotates setting up a vibration. A prop that's been ever so slightly bent can take out a shaft support bearing in a few hours of skiing. No dial indicator? Rig up some sort of metal pointer to the shaft, such as tape some piano wire (or a sharpened pencil) with duct tape on your trailer cradle using a few 2x4's, rotate the shaft and you'll clearly see if it's bent enough to vibrate. Do it on the tapered end of the shaft as well, because the shaft isn't as thick there and can bend in the tapered area easier than the straight area. You can have a straight shaft and the tapered end bent, most likely caused by striking a rock at idle where the prop walked over the rock, causing the back end of the boat to lift up.

You may have to adjust the linkage for the accel pump, but check your fuel pressure, you may have a fuel pump going bad on you. Odds are the shaft is bent, maybe not thou, so get the prop fixed and see if you luck out and the vibration goes away.

64 Skier: I rebuilt. I should say I had it rebuilt by an auto mechanic with 30+ years experience. He is an auto mechainc though. Any differnce with the marine two barrel? I've read the floats need adjusted on a 4BBl due to engine angle.