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boonedoggie

Prop isn't spinning correctly

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boonedoggie

Not sure what my problem is but sometimes when I'm pulling a skier out of the water the engine revs and the boat loses power as if the prop isn't spinning but the drive shaft is still spinning. So far, it happens for about 1/2 a second usually in the middle of the pull-out and then resumes power pulling the skier the rest of the way out. What do I have going on here?

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bb01760
Not sure what my problem is but sometimes when I'm pulling a skier out of the water the engine revs and the boat loses power as if the prop isn't spinning but the drive shaft is still spinning. So far, it happens for about 1/2 a second usually in the middle of the pull-out and then resumes power pulling the skier the rest of the way out. What do I have going on here?

Did you check the transmission oil?

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skicrave

Yep, your ATF is low and needs to be topped off before you do some serious damage to your transmission.

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boonedoggie
Yep, your ATF is low and needs to be topped off before you do some serious damage to your transmission.

THANK YOU!!! :)

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Surfin247
Not sure what my problem is but sometimes when I'm pulling a skier out of the water the engine revs and the boat loses power as if the prop isn't spinning but the drive shaft is still spinning. So far, it happens for about 1/2 a second usually in the middle of the pull-out and then resumes power pulling the skier the rest of the way out. What do I have going on here?
Are you using Perfect Pass. When surfing I get the same thing for a split second after I put it under heavy load. I think it is so you can idle around slowly with the cruise on and not have it activate. The cruise doesn't fully engage until you hit it hard or go fast enough. There is that slight hesitation before PP fully engages. Try it with pp off and see how it handles. If you are totally manual then the others are right check transmission. Edited by Surfin247

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skicrave

If you're getting engine revs without a matched surge in momentum, something isn't right in the drivetrain. Really the only thing it can be is the transmission slipping.

If there's a dead spot in the throttle, where the engine RPMs aren't increasing, then that could be related to Perfect Pass (and you probably need to adjust the linkage where the servo motor meets the throttle cable at the engine), but that's not how the system is designed to operate.

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vette-ski

I'm not sure I agree. OP says the drive shaft is spinning but not the prop. If the trans were slipping, the drive shaft should slow down too. Is there any pitting on the prop? That would be a sign of cavitation. Cavitation is like spinning your tires on your car. Wheels spin but you don't go anywhere. That's the only thing I can think of if the shaft IS spinning and the boat hesitates.

Edit: Although I will say that it is probably hard to detect rpm by just looking at the drive shaft. At the hesitation point, it may be difficult to see the shaft spinning at a lower rate, so it could still be the trans slipping. I just based my response above on what was given.

Edited by vette-ski

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88buskier

I had an older boat that would move forward but all of a suddon motor revs up and boat slows. I found out that the prop had a rubber sleeve where it slides on the shaft that had spun. (its actually part of the prop, not the shaft) The reason for the rubber is in case you ground the prop, it would be better for the prop to spin than to destroy the running gear.

I had to replace the prop.

I dont have a clue if your boat has the rubber insert on these boats, but just trying to help.

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jshap
I had an older boat that would move forward but all of a suddon motor revs up and boat slows. I found out that the prop had a rubber sleeve where it slides on the shaft that had spun. (its actually part of the prop, not the shaft) The reason for the rubber is in case you ground the prop, it would be better for the prop to spin than to destroy the running gear.

I had to replace the prop.

I dont have a clue if your boat has the rubber insert on these boats, but just trying to help.

The newer boats have a small metal "key" that fits into the driveshaft and holds the prop in place. It's designed to give if the prop hits something big to save the driveshaft. I doubt the key has gone bad or the prop probably wouldn't spin at all. Might be worth a look though, it is a soft metal.

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88buskier

The prop I am refering to also had a key. But still had the ability to spin out on the rubber. Wish I had better info...

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jshap

Ahh gotcha...my prop doesn't have any rubber between the shaft.

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SacRiverRat

How do you know the shaft is spinning but not the prop?

I suspect the OP was just making a statement that his engine is running but he isn't moving - not specifically sighting that he has identified the problem to be the connection between the prop and the driveshaft.. Dontknow.gif

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skicrave

I agree with Troy, although if he did confirm that the driveshaft was slipping then that would confirm that it's probably the key on the driveshaft, and that the prop is slipping on the shaft.

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Surfin247
Not sure what my problem is but sometimes when I'm pulling a skier out of the water the engine revs and the boat loses power as if the prop isn't spinning but the drive shaft is still spinning. So far, it happens for about 1/2 a second usually in the middle of the pull-out and then resumes power pulling the skier the rest of the way out. What do I have going on here?
Do easy things first, If using PP turn off go to manual and see if you can recreate problem. If still there check prop blades also see if there is play in your prop without the shaft moving, if so tighten prop nut. Still not solved watch the bolts on shaft coupler and see if they become clearer when accelerating, also would be good if driver could be watching RPM's in digital mode if possible. My 95 Echelon has a digital RPM read out so you would notice if the RPM's increased rapidly for a split second then settled down. PP has a RPM mode, but never used it ,and not sure if there is a digital readout when it is not active. If you rev out and the spotter sees the bolts clear your tranny is pobably slipping. Couldn't hurt to check level or change completely. I suction all my ATF out through the dipstick then put in the amount the manual says it holds. I have a mark on the dipstick showing the level when sitting on my lift, so I don't need to test it hot. It has worked great for 3years and 400hrs.I usually get a little leakage from listing the boat from side to side,but I just top it off in between oil changes. Because we primarily surf with this boat I change ATF when I change engine oil (50hrs.) If this doesn't work check alignment, still no good ,your key on the shaft at the coupler end may have a problem, since involves a bit more,you might want to have someone professionally look at it because only real thing left is transmission.

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Green_Giant

At first read, I would have guessed a moment of cavitation for whatever reason.

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MalibuTime
Not sure what my problem is but sometimes when I'm pulling a skier out of the water the engine revs and the boat loses power as if the prop isn't spinning but the drive shaft is still spinning. So far, it happens for about 1/2 a second usually in the middle of the pull-out and then resumes power pulling the skier the rest of the way out. What do I have going on here?
Are you using Perfect Pass. When surfing I get the same thing for a split second after I put it under heavy load. I think it is so you can idle around slowly with the cruise on and not have it activate. The cruise doesn't fully engage until you hit it hard or go fast enough. There is that slight hesitation before PP fully engages. Try it with pp off and see how it handles. If you are totally manual then the others are right check transmission.

I'd say check the transmission before you drive it again, then turn off PP if it is on and still doing it. Also, this sounds like the symptoms of a bit of cavitation, the prop creates an air pocket and looses a bit of grip on the water, then re-engages. Although, since bb and skicrave dialed in on transmission, good bet there you are.

edit- ok guilty of responding to the OP without reading the whole thread first. :blush:

Edited by TheBlackPearl

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