Wrong Venturi Cluster, Power Valve, and Main Jet for my Setup

cptbraine40

Petty Officer 3rd Class
Joined
Apr 13, 2012
Messages
75
I am always learning something new about my boat and just learned this:

I have a 1991 Mercruiser 3.0 (lx) 135hp with a Mercarb (trust me, it is a Mercarb and not a Rochester)

I went to rebuild my carb and noticed that I have the following:
Venturi cluster 442. Power Jet of 0.74 Main Jet of 1.45.

After doing some reading and research I realized that my carburetor is built for the older mercruiser 3.0 that were 115hp. To be up to par with my engine, Mercruiser 3.0 (lx) 135hp I should have a Venturi Cluster of 465 Power Jet of 0.75 and Main Jet of 1.6.

Will replacing the venturi cluster, power jet, and main jet with the proper ones make a huge difference in power and performance? I guess I really want to know if it would be worth it to correct this or just leave as is. I know that I only have a 135hp but I just want to make sure that I have every bit of power out of it.

Thanks,
Brian
 

Maclin

Admiral
Joined
May 27, 2007
Messages
6,761
You need to change the carb tuning to the specs you have to not only gain some power but to prevent engine damage. What is happening now is the carb will be leaning out at the top end and this could cause damage due to detonation and/or higher combustion temps.
 
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