40hp mercury

ptl

Cadet
Joined
Jun 20, 2004
Messages
6
hi i have a 1978 40hp mercury outboard motor,when i give it full throttle it just kind of whines and doesnt go any faster then if it is at 3/4 throttle
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: 40hp mercury

To Merc troubles.
 

mcginleyc

Seaman Apprentice
Joined
May 3, 2004
Messages
38
Re: 40hp mercury

Well ptl we need some more info than that. Any descriptions of sounds or anything else would help. It is either a fuel problem, which I would bet on, or a timing problem or something as simple a a prop with too much pitch or marine growth on the bottom of the boat. Post again and add any info on if the boat has been winterized, or stored for an extended period.
 

ptl

Cadet
Joined
Jun 20, 2004
Messages
6
Re: 40hp mercury

Originally posted by mcginleyc:<br /> Well ptl we need some more info than that. Any descriptions of sounds or anything else would help. It is either a fuel problem, which I would bet on, or a timing problem or something as simple a a prop with too much pitch or marine growth on the bottom of the boat. Post again and add any info on if the boat has been winterized, or stored for an extended period.
 

ptl

Cadet
Joined
Jun 20, 2004
Messages
6
Re: 40hp mercury

hi at low speed the motor runs and sounds fine but if i give it full throttle it makes a high pitch whine,it sounds like the motor is going faster but not moving the boat any faster,if i back off on the throttle a little it sounds normal.could something be slipping at full throttle?thanks
 

Dman

Petty Officer 1st Class
Joined
Mar 6, 2002
Messages
251
Re: 40hp mercury

Check your prop. Might be a spun hub in the prop if I'm understanding you right. Try a different prop that you know is good. <br />Dman
 

ptl

Cadet
Joined
Jun 20, 2004
Messages
6
Re: 40hp mercury

Originally posted by Dman:<br /> Check your prop. Might be a spun hub in the prop if I'm understanding you right. Try a different prop that you know is good. <br />Dman
 
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