OMC V6 runs does not develop full power

[ronald52]

Have 1989 Stratis with V6 Chevy engine 4.3L and OMC I/O engine and drive. New carb installed, new plug wires installed, checked fuel filter. Runs good up to 3000 rpm but starts running rough at higher rpms. Max's out at about 3300 RPM wheras 4200 RPM is the max. Any ideas what the problem could be. Thanks

 

[SpinnerBait_Nut]

Re: OMC V6 runs does not develop full power

Welcome to iboats Ronald.
This belongs in the Merc/Volvo/OMC I/O forum.
I will move it there.

 

[180shabah]

Re: OMC V6 runs does not develop full power

your WOT with a 4.3 should fall between 440 and 4800. The carb may be new, but has it been tuned for your engine? Are you getting enough fuel to supply the engine at higher revs? What is the condition of your ignition system?

 

[searay3]

Re: OMC V6 runs does not develop full power

Start with a full tuneup, cap, rotor, etc. Check for water in the fuel, replace the fuel filters/ water seperator if you have one, check the anti siphon and fuel tank for garbage. Since the carb is new, I will assume you changed the inline filter where the fuel line enters the carb. If you don't know the history of the motor, compression check can tell you a lot before you start throwing parts and money at it..If the ign coil is old or original, I would replace that too..

 

[ronald52]

Re: OMC V6 runs does not develop full power

Turns out carburetor was jetted wrong. Rebuilt and installed old carb, replaced plug wires, distributor cap and rotor. Problem solved. Thanks for the help.

Start with a full tuneup, cap, rotor, etc. Check for water in the fuel, replace the fuel filters/ water seperator if you have one, check the anti siphon and fuel tank for garbage. Since the carb is new, I will assume you changed the inline filter where the fuel line enters the carb. If you don't know the history of the motor, compression check can tell you a lot before you start throwing parts and money at it..If the ign coil is old or original, I would replace that too..

 

[ronald52]

Re: OMC V6 runs does not develop full power

Turns out carburetor was jetted wrong. Rebuilt and installed old carb, replaced plug wires, distributor cap and rotor. Problem solved. Thanks for the help.

Start with a full tuneup, cap, rotor, etc. Check for water in the fuel, replace the fuel filters/ water seperator if you have one, check the anti siphon and fuel tank for garbage. Since the carb is new, I will assume you changed the inline filter where the fuel line enters the carb. If you don't know the history of the motor, compression check can tell you a lot before you start throwing parts and money at it..If the ign coil is old or original, I would replace that too..

 

[ronald52]

Re: OMC V6 runs does not develop full power

Turns out carburetor was jetted wrong. Rebuilt and installed old carb, replaced plug wires, distributor cap and rotor. Problem solved. Thanks for the help.