Black Spark Plugs - Hotter plugs needed?

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I have a 76 FJ40 with the 2f, non-usa Toyo vacuum dizzy.

I was having HELLACIOUS running problems after it was parked for the winter.

I changed the points, fuel filter(s) and re-wired the carb-area wires. My plugs were NGK BPR5EA-L's, only a year old. They were uniformly BLACK, more sooty than oily.

I switched the plugs to NGK BPR5ES-11's, which is what NAPA gave me, gapped at .039-.040.

The engine runs WAY better now and I'm wondering if I need a carb rebuild after all or maybe just hotter plugs.

If I wanted to try hotter plugs in this 2F, what can people recommend? Also, a previous witch-doctor removed the ignitor from the coil and I now have just a coil set-up, with no ignitor.

Many thanks!!! :p
 
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Do I lean out the mixture with the adjustment screw?
Idle mix web.jpg
 
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Cdaniel

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+1 to the carb adjustment advice. Not familiar with Toyota carbs, but generally idle mixture screws only effect what happens at idle. If your rich condition is happening at speed, then something else inside may be out of whack. Could be your long term park left some gummy/varnishy junk internally blocking some sort of air passage. Or some other mechinism is sticky.
 
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+1 to the carb adjustment advice. Not familiar with Toyota carbs, but generally idle mixture screws only effect what happens at idle. If your rich condition is happening at speed, then something else inside may be out of whack. Could be your long term park left some gummy/varnishy junk internally blocking some sort of air passage. Or some other mechinism is sticky.


cdaniel: just saw your post & this makes sense. I am leaning towards a carb rebuild, I think. I already cleaned the carb as much as possible without taking it apart. I also did the hi-rev, hand on air-horn technique.

I wonder if the new plugs will likely just get messed up again pretty soon.


I ran Sta-Bil through the carb prior to winter as well but who knows.
 

Cdaniel

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Fouled plugs can be cleaned all right if they haven't been run like that very long.

Could try some fuel system cleaner in the tank and see if you can free something up.:meh:

If it ran when you parked it, could be just a little workout would help.


O yeah the Stabil. I've used that stuff in my motorhome and generator with mixed results. I think if the mix isn't just right it can cause problems
 
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The mixture screw only adjusts the idle circuit.

The main circuit is metered through jets or a combination of jets and rods depending on the carb. These are almost always hard parts that can be replaced for adjustment. Generally if the carb ran OK before, these should not need adjusting.

Nearly all carbs have am accelerator circuit to provide more fuel during acceleration. It's possible that if an air bleed is gummed up for the carb to pull fuel out of this circuit, depending on the carb.

Some carbs have a power value (usually those with metering rods do not). These usually have a diaphragm, which if broken can dump a lot of excess fuel into the engine.

I'm not running the stock carb, so I do not know which of these may apply in this case. These are general guidelines.

One thing that does apply universally is gummy crap in the carb, which can block air bleeds. This can result in lean or rich conditions, depending on which bleed is plugged.

Another thing universal to all carbs is fuel pressure. Higher fuel pressure has the same effect as raising the height of the float, because the higher pressure can force the needle off the seat. This can result in overly rich conditions or even flooding.

A worn needle tip or seat can also cause a rich condition by not being able to shut off the flow of fuel completely.

A clogged air cleaner can also cause rich conditions, but it would have to be REALLY clogged.
 
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If you are taking short trips and never getting the engine up to operating temps for a period of time, your plugs could look like that. Since you just replaced the plugs, and if she's running ok, I'd take her for a fair spin and then go from there. (my $.02)
 
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Thanks for the excellent info. I hear ya on the Sta-Bil - I may have used too much.

Also, short trips without the engine heating up fully is probably right on. I need to take the FJ out for a long run, I think.

In any event, sending the carb to Mark's Off Road won't hurt anything.
 

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