2008 f250 exhaust bubbling

[teamfishit]

I recently replaced my port side lower unit because gears and bearings.I was runinng out to fishing spot at about 4000rpms when i heard a horrible noise and the port engine shut down. I first thought i hit something trimmed up but didnt see anything i tried turning motor over but immediately heard problem.So i limped back to the mariner and pulled the boat out.I spun prop and heard something in lower unit not right so i pulled lower unit and found to be terminal. So i opted for a new oem counter rotating lower unit. I just installed in today and when i started it up i could hear that i was a little louder than the starboard motor and after looking closer i notice exhaust bubbling at the front mid section right at the bottom of the plastic covers and also notice that there wasnt exhaust coming out of the bottom back screens like the starboard motor. Im wondering if it is something I did putting the new lower unit up or if something more happened because of lower unit failure. Anyway sorry for the extended post. Any help to get me back the the fishing grounds is much appreciated. thanks

[99yam40]

Something different about the lower units maybe, are you sure you ordered the correct one?

Can you drop it again and inspect and compare to the old one?
Sounds like exhaust is system connections not all there

[teamfishit]

yes thank you for your replies. It was my fault I had asked the dealer when I purchased the lower unit if it was ready to go and he said yes so I didnt pay to much attention except a little grease and topped gear lube but I dropped the lower unit this morning and found exhaust rubber gasket was missing so i went home and grabbed the one off the old unit problem solved. headed off shore didnt catch much but motors ran great. The dealer also said there was really no break in for the lower unit, I read to change gear oil after 20 hours and kind of alter speeds and no wide open for to long , if anybody knows anything different please let me know. Thanks again

[boscoe99]

yes thank you for your replies. It was my fault I had asked the dealer when I purchased the lower unit if it was ready to go and he said yes so I didnt pay to much attention except a little grease and topped gear lube but I dropped the lower unit this morning and found exhaust rubber gasket was missing so i went home and grabbed the one off the old unit problem solved. headed off shore didnt catch much but motors ran great. The dealer also said there was really no break in for the lower unit, I read to change gear oil after 20 hours and kind of alter speeds and no wide open for to long , if anybody knows anything different please let me know. Thanks again

Yes, the seal and the seal damper guide don't normally come with a new lower unit. They have to be removed from the old unit and transferred to the new one.

[boscoe99]

<<So i opted for a new oem counter rotating lower unit>> Smart move to go with Yahama new LU. Rebuilt LUs are worthless IMO. Been there - done that.

Wish I could help you with the "noise". Don't think it has anything to do with the new LU. I would call a mechanic to the boat and ask him?

Why is that?

How is it that Fujimotor can build up a lower unit back in Japan but it seems that almost no one else around the world knows how to do it properly.

[TownsendsFJR1300]

Re break in;

You don't have to vary the RPM's for the LU, that's more for seating the rings in the power-head when new.

I would change the LU oil after that 20 hours.

You may get little to no metal coming out, but it is a new unit and parts are breaking in together. Of course there's no oil filter so any particles circulate and exacerbate wear.

Its very cheap INSURANCE for your new LU too...

[teamfishit]

thank you fjr1300