TOPIC: 1977 Merc 1150 - Disabling Carb Economizer Circuts

I have a 1977 Merc 1150 that is mounted on a 1981 Glastron Carlson C-500. I have had the boat/motor since 1981 and have never had an issue with the motor but everything I read says you should disable the economizer circuits on the carbs. For information I only run ethanol free gas with synthetic merc oil at 50:1.

Questions:
1. Is putting a BB in the tube all you need to do to disable the economizer circuit? I have seen differing opinions on plugging the jet.

2. Does anyone advise against disabling the circuit?

Thank you,

Kevin

No BB required.
You can simply remove the economizer jet, or disconnect the tubing from the float chamber top.
The problem with the economizer system is that it was designed to keep the mid-range RPMs more economical, but the mid-range RPMs are already really lean since that is the area of throttle advance that has the timing at WOT, and the carburetor butterflies are still pretty well closed since the secondary pick up has not engaged yet.

doc F

Doc F,

Thank you for the information. If I remove the economizer jet do I need to put a plug in the hole?

Thanks,

Kevin

No need to block the hole where the jet came out. For mine i remove the tube, block it and replace it. Looks original and there is no opening in the side of the carb for crud to accumulate.

The economizer tubes purpose is to reduce the atmospheric pressure above the fuel in the bowl and lean out the mixture as a result. By either removing the vent or blocking the tube you prevent that pressure reduction. Fuel/oil mix is not involved, just the stoichiometric air fuel mixture.

Thank you for the information.

Kevin