I am new too to fixing carburetors and I have a question. I just finished putting a used carburetor back on my '60 I noticed that when my '60 is in neutral the RPM pulses. The low RPM are between 1250 and 1500 and it pulses to 1750 to 2000. I read other threads and it appears that most carburetor problems on an FJ60 are a result of vacuum leaks. Will this cause the pulsing as well, or their something else that I should check/adjust first? The carburetor that I put on was a used carburetor and had not been rebuilt but came of a nice running FJ60 if that helps.
RPM Carb Pulse
- Thread starter flyingyahoo
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Butt Ugly Chuck
Fish Biologist
Q-1 Are your idle rpm's that high? Should be about 650.
Q-2 Are the rpm's jumping in response to the AC compressor kicking on? One of the vacuum lines connects to an AC idle up circuit (from a diaphragm on front drivers side of carb, vac line runs to a vac switching valve on the drivers side fender, another vac line runs from that to a vacuum source on the rear of the manifold).
Butt
Q-2 Are the rpm's jumping in response to the AC compressor kicking on? One of the vacuum lines connects to an AC idle up circuit (from a diaphragm on front drivers side of carb, vac line runs to a vac switching valve on the drivers side fender, another vac line runs from that to a vacuum source on the rear of the manifold).
Butt
Do a search for "lean drop". You will find procedures how to adjust the carb for proper idle mixture and idle speed. The lean drop adjustment should be done with the engine at operating temp, the choke off and the air conditioning off. If you still have problems, start checking to make sure all your vacuum lines are properly connected.
I see the purchase of the emissions manual in your future...
I see the purchase of the emissions manual in your future...
- Thread starter
- #4
RPMs
Butt,
I will check at lunch to see what the RPMs are at idle. I was just going from memory this morning but will check to make sure.
Yes the AC was on. I will trun this off and see if I still have the problem.
2mbb,
Thanks for the advice for a "lean drop" search I would have never known to search for those key words. Will research tonight.
I actually have the Emissions Mannual FSM as well as the other FSMs and they have helped out a lot.
Appreciate the help and will post up the results.
Butt,
I will check at lunch to see what the RPMs are at idle. I was just going from memory this morning but will check to make sure.
Yes the AC was on. I will trun this off and see if I still have the problem.
2mbb,
Thanks for the advice for a "lean drop" search I would have never known to search for those key words. Will research tonight.
I actually have the Emissions Mannual FSM as well as the other FSMs and they have helped out a lot.
Appreciate the help and will post up the results.
- Thread starter
- #5
Idle with AC off
So I went home for lunch and started the truck. With A/C off it idled at 1000 RPM with no pulse. As soon as I turned on hte A/C idle went to 1250 and started pulsing. Looks like I may have narrowed it down a bit.
So I went home for lunch and started the truck. With A/C off it idled at 1000 RPM with no pulse. As soon as I turned on hte A/C idle went to 1250 and started pulsing. Looks like I may have narrowed it down a bit.
The a/c idle speed screw is set too high. The screw is the only adjustment screw on the front of the carburetor. Unscrew (counter clockwise) the scew to reduce the idle speed until the pulsing stops.
Your RPM is running a little high too. Technically should be 650. The lean drop adjustment procedure is in the back of the emissions manual. Check it out...
- Thread starter
- #7
A/C idle screw
2mbb,
Thanks again for the advice. I will adjust the A/C idle screw tonight. I found the "lean drop" method in the FSM emissions mannual that you referred to and will try that tonight or tomorrow. Thanks for all of your help.
2mbb,
Thanks again for the advice. I will adjust the A/C idle screw tonight. I found the "lean drop" method in the FSM emissions mannual that you referred to and will try that tonight or tomorrow. Thanks for all of your help.
