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2002 150 xr6 clutch chatter

M

mvovos

New member
New to forum, I have a 150 xr6 that I recently have developed a cluncking noise in the lower unit while in gear until it reaches about 1200 rpm after that smooth. I took it in to my dealer and they told me with a ss prop this is common clutch chatter and I will have to live with it I have tried numerous hub kits nothing seems to work I cant believe that nothing can be done to fix it. It also makes the same noise with my aluminum prop on it. Has anyone else had this problem and what did you do to fix it
 
It's called "Clutch Dog Rattle". The clutch dog is a gear mounted on the prop shaft that slides back and forth, at the command of the shifter cam to select between the gears.

I get it on my 90 when I use my 13 1/4 x 24 XP Ballistic SS prop. It's caused by the prop and the cylinder explosions not being in sync. At low speeds when the piston isn't popping, there is a relaxing of the gear train. When the next cylinder fires there is pressure on the train to turn the prop shaft.

Meanwhile the prop is merrily turning in the "semi-solid" water at it's own constant pace. With a big heavy prop, when the slack is taken back up there is a clunk or rattle as it is known. Mine is most obnoxious when lining up for, and loading onto the trailer. To stop it, I shift in and out of N to maintain the desired headway with out the clunking. If I put my 21P, non-XP Ballistic SS on, I don't have that problem, course the prop turns easier in the water so it gives a little when the impulse occurs.

I use Merc HP lube which is always blue black when I change it and the magnet on the drain plug has very few filings.

HTH,
Mark
 
mvovos said:
Texasmark shouldn't do it with aluminum prop should it
Click to expand...

Well, that's the confusing part. I agree it shouldn't but there maybe a 3rd player here somewhere. What's the dia and pitch of the alum vs the SS? What brand is the alum and SS? Could be extra slop in your lower unit. Could be the way your engine is setup on your boat. Could be the way the water from the boat is introduced to the engine lower unit. Who knows, but my bet that is what it is and now you know how it is caused.

Mark
 
That's the weird part I have owned this boat for 3 years and it came with the stock 21 pitch aluminum and it never made this noise before. I decided to put a ss prop on this year to get better all around performance and it is a 19 pitch tempest plus with the large vent plugs in and just love the performance of the prop but hate the noise, so I put my aluminum back on and ran it with ear muffs on and heard same noise so that's when I took it to a dealer and started experimenting with different hub kits floe torq II was the first no change then went to a RBX hub which maybe seemed a little better. That's the history so far
 
On hubs, the prop needs to be locked to the shaft. On my Merc the torque spec for the prop nut is 55 ft lbs. Yes, a flopping prop could induce that noise. Your prop pitch numbers close enough that I wouldn't enter that as a possible cause. Besides you said you ran with the alum before and didn't have the noise. I can understand what you said about the performance enhancement with the Tempest +.

You said you ran the old alum on ear muffs? You mean in the driveway on the water hose/adapters to the engine. If so, I wouldn't qualify that as a valid comparison. So, it may be SS prop related. I think the Tempest comes with a plastic/brass hub kit; not pressed in rubber. If that has any slop in it, it could cause the problem. I'm just guessing. I'm not there. Best I can do.

Mark
 
Thanks for your help Mark I'm pretty sure it is prop related I have a RBX hub kit in the prop now it is a rubber one instead of mercs plastic and it is torqued to 55 lbs I did talk to some other guys that went to the torque flo IV hub system and said they had good results will try one maybe. Thanks again for your input I appreciate fellow fisherman/boaters inputs.
 
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