Lower unit

[tbrownarcher]

After some time we have, between getting things paid to be done and doing other stuff ourselves, gotten our Johnson 150 v6 1999 motor fixed (maybe). It has a noise in it but we think it might be the lower unit? Can the lower unit be in such a state that it would sound like a rod knocking?

We have run the motor while the boat was secured to the trailer in the water both in gear and not in gear at high rpm. Neither way is there any noise we can detect. However when we take it out on the lake it seems to have a knocking sound. Because we don't hear it at the dock while on the trailer we think it's the lower unit or if i don't have the right terminology then the gear case?

We drained and filled the gear case this afternoon and got very little oil out of it. Maybe a cup! This oil was milky gray with filings in it as large as a large grains of sand (1/16") in size. The filings were attached to the magnets on the screw plugs.

The boat has a hot foot in it or something like a hot foot so the gear shift is not attached to the throttle but the gear shift does change the forward or reverse. However it does not work well at all in fact when I brought it back to the house this afternoon I had been trying to get it into reverse and it actually went into forward instead and the gear shift handle was completely pulled back.

I don't want to have to tear into it but it seems I may have too. We have a service manual that tells about all the tools necessary to work on the gear case. Is it a hard job? Is it too complicated? I'm looking for experience to help because I need help. LOL

Can it be the linkage? Well, I'm sure it could be but is it likely ? Why would it go into forward with the handle pulled completely back? This is a 1999 Triton 18' boat.

Thanks,
Nate

 

[jonesg]

Re: Lower unit

Did you have new drain screw seals in place?

The clunk might be because you had no lube left.

 

[tbrownarcher]

Re: Lower unit

Jonesg:
Lol Yep .. had the screws back in and filled with the proper oil.

I did not know I had mentioned a klunk.


Thanks,
Nate

 

[Benny1963]

Re: Lower unit

you can do what i did take lowerunit off put waterhose on supply line to powerhead and run if you still have the clicking or knocking noise run a comp check then pull the plug with low reading put something in spark plug hole i use 3/8 extension push on piton while turning flywheel if ya have play then you have bad wrist pin bearing or collapsed skirk on that cyl has it been overheated to were the alarm went off

 

[freddyray21]

Re: Lower unit

milky gray oil with filings in it is not a good indication of a healthy gear case. it could be a gearcase issue, but hard to tell. Just filling it with oil will not cure it. And dropping the lower and hooking it up to water will probably not tell you anything either. The fact that you don't hear it out of gear doesn't mean anything per se. It is under a load that the knock seems to be happening and the only way to test it is on the water or with a test wheel in a tank so you can simulate load. I would think on the water a gearcase issue would be harder to hear than a rod knocking in a motor. Is the cowl on tight? Take the cowl off and run it on the water and see if it does it.

 

[tbrownarcher]

Re: Lower unit

freddyray:

Wouldn't running the motor in gear while tied to the trailer be load enough? We neither hear the noise then nor when it is out of gear?

We have the lower unit ready to drop now. Just need to get the oil all drained out. The oil i put in it yesterday is uncolored but it has LOTS of filings in it and the magnets on the screws have a christmas tree of filings on them.


We surely have lower unit problems but maybe both motor and lower unit.?

thanks,
Nate

 

[tbrownarcher]

Re: Lower unit

I went through the johnson manual instructions to take the lower unit off. I can get it to drop down a bit over an inch and it won't come anymore. What could be holding it?

Thanks,
Nate

 

[freddyray21]

Re: Lower unit

shift linkage needs to be unhooked. If you have that many filings then you are probably looking at gears and bearings in the lower unit. Might be cheaper to look for a used lower unit.

 

[tbrownarcher]

Re: Lower unit

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

 

[Chris1956]

Re: Lower unit

Nate, Removing the waterpump impeller is the easy part. Pulling the propshaft bearing carrier is much more challenging.

I recommend you price a used lower unit, and then add up the costs of three new gears, and their associated bearings and seals, for your lower. You need to see if it makes any sense to try to rebuild it.