3.0 2bbl carb adjustment after rebuild

[Pdevito]

I rebuilt my carburetor and I put it in and it fired up just fine on one and a 1/2 turns.The RPm's are at a 1080 right now and I know I have bring them down with muffs to about 7:40 or 8:40. Then in the waTer idling in gear to 650. My question is should I adjust the mixture first and does that drop rpm.

 

[Scott06]

I rebuilt my carburetor and I put it in and it fired up just fine on one and a 1/2 turns.The RPm's are at a 1080 right now and I know I have bring them down with muffs to about 7:40 or 8:40. Then in the waTer idling in gear to 650. My question is should I adjust the mixture first and does that drop rpm.

Yes I would set the ignition timing, idle mixture ( richen and then lean to a stumble set in middle between those two extremes), then set idle speed screw to like 750 on muffs

When you get it in the water and under load you can fine tune the idle.

Note you may need to adjust the throttle cable as it may not be allowing the carb to return all the way to hit the idle stop screw

 

[Pdevito]

Thanks. I checked cable for bottom out on carb. Let it warm up reduced rpm a little started to run rough. Increased rich counterclockwise to 2 turns out seem to be better. Rpm now fluctuates between 720 and 800. On spark plug wire. How am I doing?

 

[Scott06]

Thanks. I checked cable for bottom out on carb. Let it warm up reduced rpm a little started to run rough. Increased rich counterclockwise to 2 turns out seem to be better. Rpm now fluctuates between 720 and 800. On spark plug wire. How am I doing?

Not sure what you mean by On spark plug wire?

Would think the idle would stay steadier than 720-800 rpm but hard to tell from my keyboard

 

[Pdevito]

Clamp on tach on plug wire

 

[Pdevito]

The dash tach stays steady but 900

 

[Pdevito]

Got it stady at approx 750 to 775 on dash tach. Moved mixture screw 1/4 turn up got rougher. Then backed off 2/4 was rough there set 1/4 higher seems best. I guess I am looking for a perfect setting. Smooth but it seems like it will vibrate a little at any setting. What do you think always did before after last rebuild.

 

[Scott06]

Got it stady at approx 750 to 775 on dash tach. Moved mixture screw 1/4 turn up got rougher. Then backed off 2/4 was rough there set 1/4 higher seems best. I guess I am looking for a perfect setting. Smooth but it seems like it will vibrate a little at any setting. What do you think always did before after last rebuild.

The 3.0 is not a really smooth engine always vibrates some at idle if you are idling 750-775 is probably fine adjust down as needed when you are in gear on the water.

 

[Bt Doctur]

Adjust mixture for the best rpm, then adjust idle speed screw to adjust rpm

 

[Pdevito]

Is there a special adapter to use the test lead the white lead that's on the motor for RPM

 

[Bondo]

Is there a special adapter to use the test lead the white lead that's on the motor for RPM

Ayuh,..... A tach is driven from the (-) tiny terminal on the coil,......

 

[Pdevito]

Yes my question is the white lead for the test rpm. Do I use my probes and put the red in there and the black to ground. I have the clamp on for the spark plug wire but it fluctuates. Between 800 and 720 I am wondering if I use the white wire with the connecter will it be more accurate and steady. Everyone on iboats has been a great experience so far.

 

[Bondo]

Ayuh,..... What motor are you workin' on,..??
What year is it,..??

 

[Pdevito]

2006 3.0 mercruiser with alpha one 2bbl mercruiser carb