2000 90 TLRY driveshaft noise?

[Numerick]

I have a 2000 90 HP 2 stroke Yamaha with an unusual noise. Noise seems to resonate somewhere between the waterpump and the base of the powerhead. Best way for me to describe it is a ratcheting type noise or a bucket of bolts tumbling. Noise is very noticable at idle in or out of the water. Does anyone have experience with this problem? My first inclination would be a bad bearing in the middle of the driveshaft. Parts diagram does not show one. I understand it is hard to get answers without hearing the problem first hand. Thought I would try the Forum for ideas or guidance. Thanks

[robert graham]

I've been running a 1999 Yamaha 90C since I bought it new and have not experienced any noises or sounds like you describe. Drop the lower unit to inspect the water pump, drive shaft and lower unit, drain your lower unit to inspect for water or metal fragments in the oil to hopefully eliminate that as the source of the sounds. Maybe run the motor with the top cowling off to check for any loose parts, nuts, bolts, etc. that may me rattling around? Hopefully just something loose and not a bad bearing or something serious$$$

[Numerick]

Thanks, I drained the lower unit oil and it was clear of metal or debris. Ran it with the top cowling off-semi good news is that there is definatately no unusual noise from the powerhead. It is almost as if the driveshaft is loose somewhere between the powerhead and the bearing below the waterpump. Next step is to remove the lower unit and start the investigation. Just bought the 155cc Edgewater with the Yamaha. Sea trailed the boat before purchasing and the performance was great. Upon further investigation the noise just seemed unusual definately not something that should be normal. I appreciate your input.

[robert graham]

Just a thought...but if you're accustomed to the quiet purring of a 4 stroke outboard, a 90HP 2 stroke does generate some mechanical noise. But probably a good idea to drop that lower unit to inspect for anything loose...Good Luck!

[DougBradlow]

Drive shaft noise

On some Yamaha outboards they used an anti knock bushing above the water pump.If your Yamaha is supposed to have one and it is missing you will have a knocking noise from your mid section check your local Yamaha dealer in reference to your year and model and check to see if your outboard is suppose to have this bushing.You will see it in micro fish under the water pump kit listing.

[Numerick]

Thank you. The previous owner told me the waterpump was replaced prior to me purchasing the boat. I just put the boat away for the season. When I took the prop off I found fishing line wrapped around the prop shaft and the seal behind the prop was sliced in in half. Good news is that the lower unit oil had minimal water in it. Plans are to drop the lower unit in the early spring and go through it. Unfortunately I will not be able to report my findings until April. Thanks for the input from all. The waterpump bushing seems like a likely source and or the bearing probably isn't too far behind needing replacement. I have been spoiled by the quiet F200 on my Grady. Love the 2 stroke performance and keep forgetting they are rather crude compared to the four strokes. I just know there is something unusual going on in there.

[99yam40]

Water in lower unit and waiting months may not be the best idea for bearings and gears

[rodbolt17]

but it is good for techs

[Numerick]

Lower unit oil was replaced with new oil.

[robert graham]

Just curious, but was it salt water that got in your lower unit?....how long was water in there? Saltwater in gears and bearings is very bad...freshwater maybe not as bad....lot would depend on how long it was in there. good Luck!