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Lower unit or Piston Rod either or both??


tbrownarcher's Avatar
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09-22-08, 01:18 AM   #1  
Lower unit or Piston Rod either or both??

We have a triton 18' year 1999 with a johnson 150

We have taken the motor apart and replaced one piston with rod and bearings and put it back together.

We hear a noise in the motor still which sorta sounds like a Rod in the motor. However, only when we run the boat on the lake do we hear the noise. We do not hear the noise when we back the boat in on the trailer and leave it tied to the trailer. Neither in gear nor out of gear do we hear the noise when the boat is secured to the trailer. Out on the lake it sounds like a rod to me.

I wonder if the noise could be coming from the lower unit. We know there are problems there but not sure what. There are filings in the oil some are as large as a large grain of sand 1/16". The shifter was working eraticly and when I tried last to put it into reverse it went into forward instead. I brought it back.

anything anyone could inform me on would be great.

The Johnson manual goes through a whole list (half a page) of tools I need to take apart the lower unit of gear case. Is it that complicated ? There must be some pretty expensive tools there.

Thanks,
Nate

 
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Rick Johnston's Avatar
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09-22-08, 04:16 AM   #2  
Boat on trailer versus boat on lake tells me that it's under more torque when it's on the lake, but that's as far as I dare to go by reading about it instead of seeing & hearing it for myself.

You could try pinpointing the source of the sound with a mechanic's stethoscope. I wouldn't run it any more than necessary. The filings in the gear lube are signs of a failure somewhere, and if you continue to run it you could do serious damage to other parts.

At this point I think I would take it in for a proper diagnosis. Problem is, they may have to take it apart to diagnose, and that will cost money. If it is the transmission, it may not be something you'd want to tackle anyway.

Sorry I couldn't offer more help.

 
tbrownarcher's Avatar
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09-22-08, 03:57 PM   #3  
Rick:

I know there is something wrong in the lower unit so I'm gonna take it apart. In fact the case it'self is chunked out at the bottom right out on the end of the tube where the Prop fits in. There is a rubber ring around the inside of it between the prop and the housing it's self.

I am following the directions for disassembly of the water pump on page 6-6 of the OEM Johnson service manual.

Removal:

1. Remove the four screws e retaining the impeller housing
to the gearcase. Rotate the drive shaft counter clockwise to unlock the impeller cam.

2. Slide the water pump assembly off the driveshaft. Remove
the impeller drive cam f, impeller O-ring g, impeller plate h, and impeller plate gasket i. Discard the gasket.

Instruction 2 does not say to take off the IMPELLER. I assume then that the impeller should have come off with the IMPELLER DRIVE CAM. It did not come off then nor has it come off nor can I find a way to get it off. The impeller looks like it's a good impeller and I figgered I would try to save it. Otherwise I could cut it off maybe.

Can you tell me anything about this ?? Is there a tool I need? A puller of some sort that's gonna cost a bundle ??


Thanks,
Nate

 
samuari's Avatar
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09-22-08, 05:41 PM   #4  
There isn't a whole lot you can do without the propper tools. You can remove the prop and then drain all the fluid. After that remove the 2 bolts that hold the bearing carrier "behind the prop" the carrier should pull out with the reverse gear. once that is out you can see the pinion gear and the nut holding the pinion to the driveshaft. At this time a special tool is required to remove the nut. At least you can see all the gears. Good luck.

 
samuari's Avatar
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09-22-08, 05:48 PM   #5  
Ok I didn't read all the posts as far as the impeller pry it off with a screwdriver there isn't anything else holding it. Once it it off file it in the trash you want a new one I replace any impeller that is more than a year old. They are cheap and the manufacturers recomend replacing every 2 years anyway. In my opinion it's too much work to put it back in then have it fail and put a new one in anyway.

 
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