40 hp Merc efi 2004 spun timing pulley again.

[sandybay]

I have 2004 40 hp EFI that keeps spinning the the timing pulley on the crankshaft. The woodruff key rolls over and the pulley starts to slip, 3rd time happens about every 10-20 hours

 

[schematic]

try lapping in the tapers with valve grinding compound. The taper may have been damaged by the first failure caused by a loose nut...

 

[sandybay]

Its a straight shaft no taper.

 

[schematic]

is the idle speed high?

 

[sandybay]

Idle speed is perfect, I'm thinking the engine heat is causing the pulley to expand and loosen, it does not run hot that I know. It's one of my rental boats so I'm not the one using it the most.

 

[schematic]

model number?

 

[sandybay]

40elptefi

 

[schematic]

sorry, I meant serial number....

 

[sandybay]

Ot940994

 

[schematic]

my bad, sorry, I misread your post. thought it was the flywheel....

-did you use original woodruff key from Merc?
-did you replace the "load ring"?
-did you torque the flywheel nut to specs?

 

[Faztbullet]

Blue loctite is your friend....

 

[sandybay]

my bad, sorry, I misread your post. thought it was the flywheel....

-did you use original woodruff key from Merc?
-did you replace the "load ring"?
-did you torque the flywheel nut to specs?

Yes
No
Yes

 

[sandybay]

Blue loctite is your friend....

Yes loctite second time
J B weld third time

 

[schematic]

load ring is a one time crush sleeve. It applies pressure to the belt drive pulley and prevents it from slipping.
REPLACE IT

 

[sandybay]

load ring is a one time crush sleeve. It applies pressure to the belt drive pulley and prevents it from slipping.
REPLACE IT

Thank so much

 

[schematic]

Also check to see if the cam is abnormally hard to turn. its possible you have a galled bearing surface. Also check oil pressure in case the pressure regulator is stuck closed causing high torque at high speeds.
Always good to check all bases when you have a repetitive problem....