Yamaha 40HP Carb Jet Upgrade?

B

brooksa

Recruit
Joined
Mar 14, 2009
Messages
1
I have a 2002 40hp Yamaha (C40TLRA-2 stroke) and am looking at putting 50hp (50TRLA) jets in it. The 40 has one #118 & two #115 main jets and the idles are #60. The 50 has three #130 mains and the idles are #62. Do you see any problems in doing this, and I will I gain very much by doing so? Also why does cylinder 1 & 3 have #115 jets & cylinder 2 have #118 on the 40 and all three are the same on the 50 (#130)?
 
JB

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: Yamaha 40HP Carb Jet Upgrade?

Howdy, Brooksa.

Welcome to iboats. :)

The notion that using jets from a higher HP version of a block will somehow add more power is a myth, Brooksa. They will only screw up your engine.

The jets are sized according to the airflow patterns for that engine/cylinder at normal operating speeds.

You would probably gain more by changing to 50HP decals on the cowling.
 
Mas

Mas

Lieutenant Commander
Joined
Oct 3, 2006
Messages
1,656
Re: Yamaha 40HP Carb Jet Upgrade?

JB said:
You would probably gain more by changing to 50HP decals on the cowling.
Click to expand...

...or making sure your motor is properly tuned and all unnecessary gear removed from the boat to lighten the load!

MAS
 
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