Evinrude 140 1990 rpm jumps

Spenser

Cadet
Joined
Sep 18, 2010
Messages
17
Hello.
when i go in the same direction as waves or from the side, as rpm reaches 3500 - 4000, rpm suddenly goes up to 5500, but boat slows down. This however is not true when i go against waves - no slips. I thought maybe propeller slips, but then why not when going against waves? I turned the boat off, put it in gear tried to turn the propeller with my hands - it doesn't slip. There is a slight back/forth free way, but i think that's how it is designed. Does anyone know whats wrong? Thanks in advance.

Another thing i noticed is if i stop the boat, put it in reverse and forrward after that, then it goes properly again without slipping.
 

Spenser

Cadet
Joined
Sep 18, 2010
Messages
17
Re: Evinrude 140 1990 rpm jumps

I am pretty sure its something in the lower unit, but what? Is it propeller, clutch dog, prop hub?
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: Evinrude 140 1990 rpm jumps

sounds like spun prop, or one fixing to fail. draw a line, with permanent marker, from metal to metal on the prop. get the boat to do, what you said. afterwards, check the marks, if still lined up, it is not the prop. if the marks do not line up, you have a spun prop.

any prop shop can rehub, and recondition the prop, like new.
 

Spenser

Cadet
Joined
Sep 18, 2010
Messages
17
Re: Evinrude 140 1990 rpm jumps

Thanks. Just to clarify do you mean to draw a line from
like M to J on the following diargam?
propparts.jpg
 
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