Knocking noise in lower unite

[Black sea]

Need help
I have 1988 200ETXG has knocking noise in lower unite when in gear F-R. i removed prop and run it there is no noise.I don't think prop is problem because i have 3 different props,all same results. I replaced water pump plate,insert cartridge,impeller, accept water pump housing.
Thanks

[boats.net]

Check gearcase oil for water or metal on bottom drain screw magnet, if any found gearcase needs to be taken apart and check for damage.

[Black sea]

knocking noise in lower drive

There is no water in oil and no metal pieces

[99yam40]

Is the noise only at idle?
And is the prop a heavy SS?

[rodbolt17]

is this the original gearcase or has it been replaced with a later model case?
the part numbers of the insert and housing will tell.

[Black sea]

knocking noise in lover drive

noise looks like at idle speed, i have ss. and alu. props, i tried both of them same result.
I think gear case is original and i owned this boat 3 yrs, there was no noise before.

Thanks you all

[99yam40]

did you replace water pump lately or have someone replace it?
Not sure on that motor but some have the spring washers that need to be preloaded , and if they are not it will cause noise

[Black sea]

knocking noise

Yes i replaced every part recently (plate,insert catridge,impaller) accept water pump housing.
I didn't see any spring washer accept 4 bolts with spring washer holds the housing.Can housing make noise?
If there was a spring washer, what is exactly location?
I have twin engine, i checked other one there is no spring washer.What year engines have spring washer? will look at it from boats.net parts.
I am car mecanic i know what i am doing but i am new to outboard.
Thank you

[99yam40]

I have no idea what years or motors, but they will be on the drive shaft over the water pump. If you did not have to remove them to remove pump then I does not have them

[Black sea]

ok.Thank you 99yam40