Clutch Old

My Johnston outboard motor (2 stroke - 25 years old) seems to have a slipping clutch or similar. An ideas?

When we are motoring along the boat motor tends to rev higher like a slipping clutch as we don't get much forward motion when it is over revving. I have replaced the locking pin in the propeller as this broke and of course provided no motion. But this is different and an intermitant problem. Any help would be greatly appreciated.

buy a new prop. i've refurbished them before-not worth it -just buy a new one.

ONE GENUINE BRIGGS  STRATTON CLUTCH STARTER ASSEMBLY PART 298339 NEW OLD STOCK
ONE GENUINE BRIGGS STRATTON CLUTCH STARTER ASSEMBLY PART 298339 NEW OLD STOCK
$29.95
Time Remaining: 1d 20h 59m
Buy It Now for only: $29.95

Gen CUB CADET Clutch Fiber Wear Button for Old Models
Gen CUB CADET Clutch Fiber Wear Button for Old Models
$7.99
Time Remaining: 2d 19h 39m
Buy It Now for only: $7.99

Genuine CUB CADET Fiber Button for Clutch on Old Models
Genuine CUB CADET Fiber Button for Clutch on Old Models
$7.99
Time Remaining: 2d 19h 39m
Buy It Now for only: $7.99

OEM MTD 746 0488 CLUTCH CABLE NEW OLD STOCK  IJ
OEM MTD 746 0488 CLUTCH CABLE NEW OLD STOCK IJ
$15.99
Time Remaining: 3d 18h 2m
Buy It Now for only: $15.99

Genuine CUB CADET Fiber Button for Clutch on Old Models
Genuine CUB CADET Fiber Button for Clutch on Old Models
$6.99
Time Remaining: 5d 3h 44m
Buy It Now for only: $7.99

ONE GENUINE TECUMSEH KEY CLUTCH SHIFT PART 792136A NEW OLD STOCK
ONE GENUINE TECUMSEH KEY CLUTCH SHIFT PART 792136A NEW OLD STOCK
$9.95
Time Remaining: 5d 8h 30m
Buy It Now for only: $9.95

NEW SNAPPER CLUTCH BRAKE CABLE 7014521 14521 OLD STOCK
NEW SNAPPER CLUTCH BRAKE CABLE 7014521 14521 OLD STOCK
$6.50
Time Remaining: 6d 16h 35m
Buy It Now for only: $6.50

New Old Stock Genuine Ariens Part  527010000 527010 Clutch Arm
New Old Stock Genuine Ariens Part 527010000 527010 Clutch Arm
$19.95
Time Remaining: 6d 16h 46m
Buy It Now for only: $19.95

ONE GENUINE BRIGGS  STRATTON HOUSING STARTER CLUTCH PART 210400 NEW OLD STOCK
ONE GENUINE BRIGGS STRATTON HOUSING STARTER CLUTCH PART 210400 NEW OLD STOCK
$9.95
Time Remaining: 6d 18h 5m
Buy It Now for only: $9.95

New Old Stock Genuine Ariens Part  00239600 02396 Clutch Cable
New Old Stock Genuine Ariens Part 00239600 02396 Clutch Cable
$9.95
Time Remaining: 7d 3h 37m
Buy It Now for only: $9.95

New Old Stock Genuine Ariens Part  02721200 27212 Clutch Rod
New Old Stock Genuine Ariens Part 02721200 27212 Clutch Rod
$9.95
Time Remaining: 7d 3h 51m
Buy It Now for only: $9.95

New in Box Old Stock OEM Genuine Toro Lawn Tractor Electric PTO Clutch P92 6885
New in Box Old Stock OEM Genuine Toro Lawn Tractor Electric PTO Clutch P92 6885
$401.66
Time Remaining: 11d 18h 2m
Buy It Now for only: $401.66

Bolens Troy Bilt 1716582 ROD CLUTCH MTD Garden Way Part NOS New Old Stock OEM
Bolens Troy Bilt 1716582 ROD CLUTCH MTD Garden Way Part NOS New Old Stock OEM
$69.99
Time Remaining: 12d 9h 58m
Buy It Now for only: $69.99

Bolens Troy Bilt 1720675 ARM CLUTCH MTD Garden Way Part NOS New Old Stock OEM
Bolens Troy Bilt 1720675 ARM CLUTCH MTD Garden Way Part NOS New Old Stock OEM
$59.99
Time Remaining: 12d 10h 2m
Buy It Now for only: $59.99

Bolens Troy Bilt 1721027 ARM CLUTCH MTD Garden Way Part NOS New Old Stock OEM
Bolens Troy Bilt 1721027 ARM CLUTCH MTD Garden Way Part NOS New Old Stock OEM
$39.99
Time Remaining: 12d 10h 2m
Buy It Now for only: $39.99

Snapper Clutch Brake cable new old stock  50 in long
Snapper Clutch Brake cable new old stock 50 in long
$4.99
Time Remaining: 13d 23h
Buy It Now for only: $4.99

Snapper Clutch Brake cable new old stock  42 in long
Snapper Clutch Brake cable new old stock 42 in long
$4.99
Time Remaining: 13d 23h 10m
Buy It Now for only: $4.99

CUB CADET Clutch Friction Disc for Old Model Mowers Part  761 3002 NEW IN PKG
CUB CADET Clutch Friction Disc for Old Model Mowers Part 761 3002 NEW IN PKG
$41.99
Time Remaining: 15d 6h 1m
Buy It Now for only: $41.99

CUB CADET Metal Thrust Button PTO Clutch for Old Models
CUB CADET Metal Thrust Button PTO Clutch for Old Models
$7.99
Time Remaining: 15d 6h 8m
Buy It Now for only: $7.99

ONE GENUINE BRIGGS  STRATTON CABLE CLUTCH CONTROL PART 579257MA NEW OLD STOCK
ONE GENUINE BRIGGS STRATTON CABLE CLUTCH CONTROL PART 579257MA NEW OLD STOCK
$8.95
Time Remaining: 16d 6h 6m
Buy It Now for only: $8.95

Clutch Pedal off of an Old Bolens 800 Garden Tractor
Clutch Pedal off of an Old Bolens 800 Garden Tractor
$29.99
Time Remaining: 17d 20h 34m
Buy It Now for only: $29.99

7014521 Snapper Clutch Brake Cable  Old shelf stock
7014521 Snapper Clutch Brake Cable Old shelf stock
$8.95
Time Remaining: 18d 3h 1m
Buy It Now for only: $8.95

New in Box Old Stock Genuine OEM Toro Clutch Magnetic Electro Z Master 104 7756
New in Box Old Stock Genuine OEM Toro Clutch Magnetic Electro Z Master 104 7756
$323.36
Time Remaining: 19d 19h 30m
Buy It Now for only: $323.36

New old stock centrifugal clutch 7 06002 STENS 255 018 255 125 OREGON 84 004 etc
New old stock centrifugal clutch 7 06002 STENS 255 018 255 125 OREGON 84 004 etc
$29.89
Time Remaining: 19d 22h 17m
Buy It Now for only: $29.89

NEW SNAPPER CLUTCH ROD 7031050 31050 OLD STOCK
NEW SNAPPER CLUTCH ROD 7031050 31050 OLD STOCK
$8.95
Time Remaining: 20d 22h 42m
Buy It Now for only: $8.95

New Old Stock OEM Troy Bilt Clutch Coil Magnet Part  1738462
New Old Stock OEM Troy Bilt Clutch Coil Magnet Part 1738462
$63.36
Time Remaining: 22d 18h 2m
Buy It Now for only: $63.36

ONE GENUINE BRIGGS  STRATTON CLUTCH DRIVE PART 398879 NEW OLD STOCK
ONE GENUINE BRIGGS STRATTON CLUTCH DRIVE PART 398879 NEW OLD STOCK
$24.95
Time Remaining: 27d 2h 42m
Buy It Now for only: $24.95

ONE HOMELITE DRUM CLUTCH MOWER TP20 20 PART 992800 NEW OLD STOCK
ONE HOMELITE DRUM CLUTCH MOWER TP20 20 PART 992800 NEW OLD STOCK
$9.95
Time Remaining: 29d 23h
Buy It Now for only: $9.95