Another "carb issue" thread

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May 27, 2006
Central Maine
Based on the number of threads I found when I did a search, I know that carb issues are a common problem. I read a bunch of the threads, but I still need some expert advice.

First, here's the backstory: My '78 FJ 40 ran very well for several years. I had to take it out of commission for about a year while I installed a new body and had some paint work done. Although I removed the fuel tank, there might have been some residual fuel left in the carb.

Now my FJ and I are back on the road. I've put a couple hundred miles on in the past few weeks, but the FJ is not running right. It starts up beautifully, but I have to run it with the choke half on, even after the engine has warmed up to 190 degrees. At every stop sign, I have to depress the clutch and quickly pull the choke out all the way, or else the engine stalls. I've replace the fuel filter and the spark plugs. The gas tank is new, and I double-checked the lines to make sure all connections were right.

At first I thought there might be some kind of fuel starvation issue, but my mileage has gone from 12-13 mpg (last year) to half of that (or less) now. (Running with the choke half on ruins gas mileage, I bet.) In Maine, we now have ethanol in our fuel. I've been adding Stabil's marine formula to fuel that I know will sit for a few weeks.

Since everything worked so well before, I hope that maybe the carb needles are just dirty. What do you think? Is cleaning the carb needles and jets similar to cleaning those on a snowmobile, or would I be out of my league?

Thanks in advance.
Check for vacuum leaks/intake leaks. HTH
Fuel cut-off solenoid?
The idle fuel solenoid is on the top of the carb facing the fire wall. Follow the wire (or wires). It should make a click when you turn the key on. If it clicks, it probably works.
OK, thanks a bunch. It does click softly, so I suppose it is alright. I might replace it anyway although after replacing my fuel filter and checking the pump I don't think I have a fuel supply problem.

It have a kind of a loping rough idle and it will die sometimes, no obvious vacuum leaks, but tonite I will try covering the carb and see if rpms rise or not. The previous owner claims he just put a carb kit in it, and seems like a honest guy, but I wonder if he wasn't chasing the same problem....

I do have the stock carb. I see the window for fuel, is that the equivalent of a visual on a float level? Where should it be, or just filled with fuel?
If you have to choke it to keep it running, makes me think a vacuum leak is supplying enough air for the mixture downstream of the butterflys? Try to spray around the carb and each end of your vacuum hoses and see if you can isolate the problem area.
Sounds like the idle jet and possibly main jet are gunked, restricting the flow of fuel.
Disassemble and clean. Run a .85mm bit through the idle jet to get it cleaned out and improve idle quality.
Problem solved!

The solution was a three-step process:

1. I replaced the PCV valve.

2. I found a line that was unplugged, and after searching for a while, I found the spot where it plugs in. I reattached the line.

Even though I had already checked for unplugged lines before I posted my question, I decided to check again after reading some of the responses here. Just when I was ready to pronounce that all the lines were attached, I noticed an orange one hanging straight down. At a glance, it looked fine . . . but upon closer inspection, I discovered that it was not attached. It is now. (See orange line in photo.)

3. I cleaned the carb with some heavy duty carb cleaner. Thirty years of use and a year of sitting idle resulted in some gunk. Now that the carb is clean, my FJ purrs at idle.

My FJ is running well again. The black smoke at start-up is gone; the smooth idle is back; and I don't have to drive with the choke on.

Thanks for the assistance.

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