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JB3
05-09-2005, 07:36 PM
Hello,
My wife and I just bought our first Mastercraft, a 1996 Pro Star 190 with a std 350. I have a few questions that I hope you may be able to help answer. The first one is the Raw water pump vibrates a lot, especially at idle. If you rev the motor up, it smoothes out, Is this right? It also leaks water out the back of the pump, but I think I replace the seal and fix that problem.
2nd question is on the strut. I have a vibration in rev and if you turn the boat to the right under power. I do have freeplay if I move the shaft back and forth, so I think the bushing needs replaced. I don't think the shaft is bent, but how do you check for alignment once I replace the strut bushing (or is it a bearing?)

mbeach
05-09-2005, 08:41 PM
Hello,
My wife and I just bought our first Mastercraft, a 1996 Pro Star 190 with a std 350. I have a few questions that I hope you may be able to help answer. The first one is the Raw water pump vibrates a lot, especially at idle. If you rev the motor up, it smoothes out, Is this right? It also leaks water out the back of the pump, but I think I replace the seal and fix that problem.
2nd question is on the strut. I have a vibration in rev and if you turn the boat to the right under power. I do have freeplay if I move the shaft back and forth, so I think the bushing needs replaced. I don't think the shaft is bent, but how do you check for alignment once I replace the strut bushing (or is it a bearing?)
not sure this will help, but be sure all bolts are secure. i noticed my belt was vibrating excessively and loose. turned out to be the alternator bolt was loose and hence belt also. sounds like more than this simple fix, however.

SKI*MC
05-09-2005, 09:43 PM
I would get a new impellor for inside of the water pump, it could be dry roted. I'm not sure what the proboem is on you second question, you might have a bent prop. Does it vibrate at higher speeds at all?

AirJunky
05-09-2005, 10:02 PM
Discussing how to do prop shaft allignment might be a bit much for a discussion group. Once it's all pointed out, it's fairly easy. Adjustments are made at the motor mounts. And alignment is measured with a feeler guage at the coupler between the trans & the output shaft.
Thats probably not nearly descriptive enough so maybe someone will have a drawing or something about it.
Sounds like your on the right track though. Vibration can easily be a minor alignment problem or a ding in the prop.

JB3
05-09-2005, 10:21 PM
Thanks for the advice. I have replaced the impellor, but that didn't help the vibration on the water pump. I think I will take the pump off and make sure it was installed on the harmonic balancer correctly. Should the impellor housing vibrate(shake) when idling ?
As far as the vibration from the prop, I do not get vibration until about 3000 rpm or when the boat is turned hard to the right under power or when in reverse.

G-man
05-09-2005, 10:27 PM
Your water leaking out the back is just a bearing that needs to be replaced. Do a search and you'll be able to figure it out I think. If by chance you need a new raw water pump I have one here for the right price.

jimmer2880
05-10-2005, 06:46 AM
It does sound like your strut bushings are worn & need replaced. It's not terribly hard, just a pain in the arse to get the first one out.

wesgardner
05-10-2005, 08:39 AM
Hey JB3,

My raw water pump also "wobbles" a bit - I've taken it off a couple times only to have it do the same thing - at speed, its OK....

The bearing inside the strut is called a cutlass bearing - its actually just a hard rubber collar with slots allowing water to flow thru with a bronze-brass outer shell - it should fit fairly snuggly around the shaft...there's prolly a written procedure here on the boards somewhere on "how to" - I've done a bunch but on sailboats after removing the shaft so I'll let one of these ski boat guys take the lead...

You'll need to get the alignment procedure clear in your mind - you actually align the motor to the shaft, not vise-versa...in fact, it may be wise to have someone do it while you watch, then you'll be able to from there on out...

Oh, congrats on the new boat

Wes

Ski-A-Rees
05-10-2005, 09:31 AM
The best thing I ever bought for my boat was a brand new water pump. Then you have an extra one for parts or you can fix it as a back up.

Granite_33
05-10-2005, 09:35 AM
My distinct memory of my housing vibrating so much was a precursor to a bearing failure.

I remember this since it was vibrating much more than usual, and was something that I had not seen before. Before I knew it, bearing pcs in the bilge. The outboard bearing gave out.

There was always some small vibration in the housing at idle. But nothing like just before the bearing came apart.

The fact that the seal was leaking may or may not have something to do with it. I believe the bearings are stainless and sealed, so a small amount of water infiltration should not cause failure.

:twocents:

wesgardner
05-11-2005, 08:36 AM
Hey All,

My crank pulley must be bent or warped or not seated tightly (although I pulled it off this weekend just for that reason and upon reinstall, same thing) I did start off last season with a new pump "just to start things off right" after purchasing the boat that I really didn't know the history of. My pump was leaking and making a grinding noise (bearing/seal shot) So at least now I know the history. There were some other things that were worn out as well leading me to the decision to replace rather than rebuild.

I think the old pump wobbled too...just can't recall...pumps at skiDIM are $100 +/-

Wes

latch
05-11-2005, 01:47 PM
Have a 98ProStar with the 350 engine. Raw water pump is leaking--rear seal. Would like to replace pump, then have the old pump as an extra. Where's best place to get new pump? Thanks for the help.

Granite_33
05-11-2005, 02:03 PM
Have a 98ProStar with the 350 engine. Raw water pump is leaking--rear seal. Would like to replace pump, then have the old pump as an extra. Where's best place to get new pump? Thanks for the help.
www.skidim.com

Before you buy a new pump, ask them about the seal. If the seal is the only issue then consider replacing that first. $20 vs $150

I bought mine from them, solved the issue.

Good Luck!

Footin
05-11-2005, 02:07 PM
I replaced the seal in mine last weekend, easy job. Got a new seal at the local inboard dealer for 10 bucks.

latch
05-11-2005, 05:12 PM
How hard is it to change the seal? Closest inboard dealer is 2 1/2 hrs away. Probably would be easier to order.

Tom Jones
05-11-2005, 08:07 PM
The raw water pump on my LT1 vibrated quite badly and kept getting worse, turned out to be the harmonic balancer. This is rare they tell me, but don't rule it out completely.

SKI*MC
05-11-2005, 09:19 PM
Thanks for the advice. I have replaced the impellor, but that didn't help the vibration on the water pump. I think I will take the pump off and make sure it was installed on the harmonic balancer correctly. Should the impellor housing vibrate(shake) when idling ?
As far as the vibration from the prop, I do not get vibration until about 3000 rpm or when the boat is turned hard to the right under power or when in reverse.


That definatley sounds like a bent prop to me... it may not look like it, but the slightest bend or dent can caue the prop to shake. Even if you keep on riding it, the vibration can make everything on your driveshft crap. I would take the prop off and have it staightened.