DF140 Mid/Lower unit rumble noise.

[ADAHeli]

G'day all I am new to the forum and appreciate any help that can be put forward.

My DF140 sat for 6 months while I was doing some fibreglass work on my boat. I gave it a service, full impeller kit, lower unit oil, engine oil, plugs, filter, internal anodes, thermostat. After the service I ran it on muffs and could hear a rattley sort of rumbling gear/ bearing noise in what I believed to be the lower unit.

I pulled the lower unit back off and when turning the lower unit by hand it felt a bit notch if you applied downward pressure. I spoke with the local shop and ended up taking the lower unit to them.

It took 2 and a half months to get it back and a surprisingly high bill. They replaced the driveshaft and fwd gear bearings, reshimmed it, new oil seals ect. Got a bill for nearly $900 AUS.

Anyway, I finally got enough other jobs on the boat finished to put the lower unit back on the engine and run it with muffs on. The noise is still there !

I read though other peoples posts on similar noises and the either come to a dead end and get no response or never report back on the issue or, the finger gets pointed towards the mid section bush.

So I pulled the mid section and removed the bush to inspect it. Bush is in good condition and there is no corrosion where it mounts. I have added some grease and will reinstall it all, but I don't believe that was the issue.

I ran the engine for a brief period with the mid and lower section, can't hear the noise anymore.

Really the lower unit should be good to go after having the shop do all the work they did, but I am sceptical.

Does anyone have any ideas of experieexperienced the same issue?

Cheers,

[catacom225]

If your saying the noise is not there when the lower unit is out then it might be higher in the engine holder, maybe the clutch shaft bearing , although i think its unlikely. What year model. look for OEM Part Number: 09262-17019

[ADAHeli]

It's a 2008.
I have reassembled the leg since my last post and run it. The grease on the mid bush made no change, I didn't expect it to but was hopeful.
I disconnected the shift cable and slightly moved the clutch engagement by hand while running to see if the noise was the clutch slightly engaging. I have ruled that out now.

I have pulled the lower unit again and am on my way to the shop that rebuild the lower unit. They have another motor there the same as mine that they can put it on to have a listen. (I live in a different island to the shop, so can't just tow the boat there on the trailer)

[ADAHeli]

Shop was pretty helpful this time.
We put my gearbox on another customers boat and ran it to have a listen, still made the noise.
Pulled it back off, removed the impeller housing, found a bit of rubber transfered to the steel housing, cleaned that off incase the impeller was grabbing and making the shaft oscillate. Also pulled the top seal to have a bit of a look to confirm that a new driveshaft bearing went in previously. All checked out.

Reassembled and trialled it on the customers boat again. Same noise, no change. Ended up leaving it with them so they can pull it down further and check the shimming.

I live in a quite remote area and don't want it to quit when I'm 90nm from home! I'll update in a few weeks once the shop gets back to me.

[ADAHeli]

Also to note. When we put the customers gearbox back on for a comparison, it made the same noise but was alot quieter. Not sure how many hours it had on it to compare though.