'77 FJ40 engine mystery???

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I'm a first time poster who has heard great things about the technical expertise on this board.

My '77 FJ40 was running great until one day driving down the road when I suddenly began to lose power (chugging as I stepped on the gas). Eventually I had to pull over. After the engine cooled down I was able to proceed for a mile or so before the power loss again worsened. The problem would intensify to the point where the engine would completely shut down.

Depending on the day, I can fire it up and drive a few miles before the problem starts, and other days it will barely run at all, chugging and missing. The only issue I found that may have played a part is that I found that I had forgotten to tighten the distributor down a short time before the problem started and it was able to turn somewhat easily.

I've also found that the gas visible in the carburetor bowl boils as the engine heats up. The temperature gauge on the dash doesn't read too high. Why???

Adjusting the distributor hasn't worked. I've also cleaned the caburetor and bypassed the ignitor (for the hell of it) along with some other trial and error troubleshooting.

I haven't tried replacing the distributor yet and I have speculated about checking out the wear on the timing gears, but that's a big project for a relatively novice mechanic like myself.

Has anyone heard of this problem or have any ideas about what I should do next? My Cruiser has been OOC for far too long.

I look forward to hearing from someone who really feels my pain. Thanks everyone!

Brian
 
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[quote author=Rock link=board=1;threadid=10274;start=msg91764#msg91764 date=1074463670]
I've also found that the gas visible in the carburetor bowl boils as the engine heats up. The temperature gauge on the dash doesn't read too high. Why???


I look forward to hearing from someone who really feels my pain. Thanks everyone!

Brian
[/quote]

This is not good and would explain the problem you are having. If you are running the stock exhaust manifold, make sure that the carburetor heater flapper valve is not stuck closed. It has a little semi circular weight and coil bimetal spring on it. Rotate the weight up and down. You might have to tap on it to loosen it up. It should move freely.
 
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That was my first thought, too. The heatriser could just corrode into place (in the cold position is most likely). Or, the spring may have corroded away or broken long ago, and it was previously set in the warm position, then recently got moved to the cold position accidentally.
 
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Fix the dist/timing and rewire the ignitor...cause it sounds like it may be a fuel delivery problem. Replace the fuel filter and check the flow to the carb. Double/triple/quadruple check to ensure the float/needle seat arrangement is working properly.
 

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