Age of my old 20hp Yamaha Outboard

[lowdouble]

I have what I presume is a late 1980s Yamaha 20hp outboard and the Diaphragm in the petrol pump has torn, so needs replacing.
The engines ID plate reads : YAMAHA 20BM, 653 S 005697.

Thanks for your help

Andrew Mcfarlane.

[boats.net]

The 20hp was only sold here in USA in 1996-1997 not sure if same as yours, here is link to a 1996 model Yamaha Outboard Parts 1996 20MLHU

[LJLJ]

old 2-stroker engine..

There was a model named 20BM where the serial no. started with 653

Mariner also did a license engine that was named Mariner 20 where the serial no started with 653. I do think that these engines are from the 70's to the beginning of the 80's.

[crnko]

yam 20bm 653

I have what I presume is a late 1980s Yamaha 20hp outboard and the Diaphragm in the petrol pump has torn, so needs replacing.
The engines ID plate reads : YAMAHA 20BM, 653 S 005697.

Thanks for your help

Andrew Mcfarlane.

Hy Andrew,
I have Yam 20BM, 653S 006533, model and it seems it doesn't exist. Was bought in U.K., 653 says year between 72-78, and ser.no. 79-80. I'm also
wandering for the exact part numbers.
Good luck