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View Full Version : Noisy Powerslot Transmission 1987 ProStar


trunderw
03-09-2008, 09:22 PM
My powerslot is noisy when it's just in idle. It makes a rattley noise. If I idle it up a little bit it doesn't make any noise. I've changed the fluid, but not done a thorough flush. Any ideas as to what could cause this?

EricB
03-09-2008, 10:20 PM
It sounds like the spring coupler drive plate is worn. I assume this in gear at idle? If so, it is most likely the plate. This plate bolts to the flywheel and is the coupling for the transmission.
To replace, remove transmission and bell housing.

6ballsisall
03-09-2008, 11:33 PM
Sounds like it could possibly be the dampener plate. 2 hour job and couple hundred to replace yourself.

88 PS190
03-10-2008, 03:31 AM
Sounds like it could possibly be the dampener plate. 2 hour job and couple hundred to replace yourself.

also a good time to inspect seals and such while its out.

trunderw
03-10-2008, 09:12 AM
Ok, that's not what I wanted to hear. Where can I get the info required to do this job? And how do I determine which of the above suggestions are the issue. It's true that when it's in gear above idle it's fine, but in gear at idle it's rattly.
I do my own basic maintenance, like plugs, oil changes, etc. but I've never worked on a transmission. It doesn't look like it's easy to get out of there...
Oh, and what will happen if I don't get it fixed? Will the thing fall apart or will it just be noisy?
Thanks

454Prostar190
03-10-2008, 01:20 PM
Trunderw,
Mine makes the same noise. Rattles at idle when in gear i.e. No Wake Zone. My transmission is full, fluid smells good and was told by the previous owner that it has always made the noise.
Anything that you learn here will help me!
Thanks! Rick

kawagaskier
03-10-2008, 02:06 PM
What is your idle RPM? Mine made the same noise, but my idle rpm was a little low (about 500rpm) causing the engine to idle slightly rough. I bumped up my idle speed to about 700rpm which smoothed out the idle and the noise went away.

trunderw
03-10-2008, 04:15 PM
I'm not sure if my tach is working correctly but it says near 500 or so. Should I bump it up a bit? Seems like it shouldn't rattle either way though...

454Prostar190
03-10-2008, 04:35 PM
Mine has a hard time idling below 1,000rpm because of the cam but, when I engage the transmission the rpms will drop to approx. 800 rpm that's when it rattles. As soon as I throttle up...900 rpm?... the noise disappears. I have just accepted it but, I do sometimes wonder, like yourself.

88 PS190
03-10-2008, 04:39 PM
Oh, and what will happen if I don't get it fixed? Will the thing fall apart or will it just be noisy?

The disc fulfills the exact same role as a clutch or torque converter in a car. It transfers the power from the engine to the transmission.
The only difference is that in a boat this peice is never engaged or disengaged.
It is just a splined center, with some springs that couple it to an outer plate.
Very simple.
If one of those springs is a bit lose it will rattle. If it goes out your boat will not move.
I would not worry about it unless the noise gets worse.
they look like this or similar depending which part you buy. http://skidim.com/prodinfo.asp?number=R140004

to replace them is exactly like changing out a clutch, you support the engine, remove the transmission which the splines slide out of the center of that. You unbolt the disc from the flywheel (like a clutch pressure plate) and bolt the new one in place. Align everything and put it together. Its a few hours worth of work, not super hard work either.

But you don't need to do it necessarily, it may be possible to loosen this plate that surrounds and covers the lower portion of the bell housing in which case if you have any bits of stuff fall out you can be pretty certain you've found the culprit.

Jim@BAWS
03-10-2008, 04:53 PM
The noise could be because your IDLE is set to low. The transmission needs between 650-700 RPMS for the transpump to properly work. The amount of transmssion fluid IS NOT an exact science. A little extra will not hurt it. It will just blow out the over flow valve.

When you add a few RPMS to the motor that is when the noise disappears. Idle should be set at just about 850 RPMs in gear
750. Try it and see of that works

Jim@BAWS

Jim@BAWS
03-10-2008, 04:58 PM
The noise could be because your IDLE is set to low. The transmission needs between 650-700 RPMS for the transpump to properly work. The amount of transmssion fluid IS NOT an exact science. A little extra will not hurt it. It will just blow out the over flow valve.

When you add a few RPMS to the motor that is when the noise disappears. Idle should be set at just about 850 RPMs in gear
750. Try it and see of that works

Jim@BAWS

trunderw
03-10-2008, 05:23 PM
Is there some screw on the carb for that? Sorry for the ignorance..never worked at that level on one of these things.

87 TriStar 190
03-10-2008, 05:43 PM
I have the same setup as you do. '87 with a power slot. Don't touch anything except the idle speed. My engine runs smooth down to about 450 rpm when not it gear. In gear at that engine rpm, it rattles and sounds terrible. An idle speed of about 700 rpm in gear should be good.
I also had an issue once with a corroded distributor cap that severely limited engine performance and "clunked" back through the transmission. Another cheap and easy fix, but it took a few days to locate.
Remember, it's a MasterCraft. It's always something simple.

trunderw
03-10-2008, 05:47 PM
Yeah, my idle speed is somewhere around 400, like a Harley under water. Any idea what to adjust to bring up the idle speed?

87 TriStar 190
03-10-2008, 05:48 PM
One other thing I did not mention above. There's a screw on the carb with a cable that's used to set the idle. If my boat wasn't tucked away comfortably for the season, I'd take a photo and post it for you to see the screw. Maybe someone else has easy access and a camera. If you move the throttle, you should find it easily.

87 TriStar 190
03-10-2008, 05:52 PM
I was writing when you replied. Move the throttle lever and look for an adjustment positioning screw that is easy to get at. While at idle, turn the screw to increase engine speed. When it gets close, shift it in and out of gear a few times while making final adjustments until you have it running smooth. Enjoy your boat. How many hours do have on it?

TMCNo1
03-10-2008, 07:10 PM
One other thing I did not mention above. There's a screw on the carb with a cable that's used to set the idle. If my boat wasn't tucked away comfortably for the season, I'd take a photo and post it for you to see the screw. Maybe someone else has easy access and a camera. If you move the throttle, you should find it easily.


It will have a spring between the screw head and the bracket! Turn right to increase idle speed. 600 rpm in gear is about right per most carbed boat owners manuals and 850 to 900 in neutral IIRC.

learjet2230
03-10-2008, 07:44 PM
Ask and you shall recieve!!
http://i263.photobucket.com/albums/ii128/learjet2230/boat002-1.jpg

Aww crap, that didnt turn out very good!! If you look closely I have it circled in red!!

trunderw
03-10-2008, 09:34 PM
Thanks all of you for the info. I'll try to adjust that when we head to the lake. Our season starts in about a month...
yippee.
oh, the hours on the motor :) 850ish
it's probably time to tear it down and redo it but i know nothing about that...
oh-lear: thanks for the pic, that helps immensly

87 TriStar 190
03-11-2008, 04:51 AM
I have 946 hours on my boat and it is not even close to a tear down. I have had it since new and I'm a maintenance fanatic, but I think you should still have several hundred hours before you need to do anything. Have you had it long? These things are tough and meant to be use. Does it have the electronic ignition system? If not, that's one thing you will want to do.

trunderw
03-11-2008, 02:21 PM
It's got whatever it came with...I've had it for a year next month...so I'm not sure how well it was cared for. It runs strong...but if I'm yanking 5 skiers up (so full throttle) I get a little smoke, otherwise it doesn't have any issues. It's no where near as clean as the other motors of that era that I see posted on here. I'm heading down to the lake in a couple weeks(where I keep it stored) and I'll take some pics of the motor and maybe you can tell me what I should do first :)

gigem75
03-11-2008, 06:19 PM
Check your ignition timing, then adjust the idle speed.

87 TriStar 190
03-11-2008, 07:29 PM
These photos should help you locate the throttle adjustment screw. It's to the right of the bracket in the close up. The screw is about 20 degrees off vertical. The close up is enlarged and isn't very clear. Hope you can make it out OK. You should be able to see the location of the close up from the larger side view. It's right under the air intake cover.
I agree you should also check the timing. Replace your distributor cover if it hasn't been done for a while. Cheap and easy.

learjet2230
03-11-2008, 08:53 PM
Ahhh, can you say riser leak!!

trunderw
03-11-2008, 10:11 PM
I've had the boat for about a year or so and have no clue what the prev owner has done. I gotta get a timing light to do the timing since I've never done that before :) so much to learn!