Suburban running slugggish...

[BIG BLUE]

So not sure what is going on. Thinking its carb related. Suburban was running fine, although always seemed to be a bit sluggish. Then last weekend took it out in the desert and was climbing a hill it lost power and died...got it started back up but it acted like it needed to clean out. Lots of black smoke. So I drove it home, never could get it over 20. Sometimes if I was sitting at idle reving it up you could here a change in the sound and the thing would clean out, no more black smoke and sound good. Soon as I put it in gear and got about 30 feet it acted like it loaded up again and would get real sluggish. I think its a carb problem. Standard Rochester 4 barrel carb that came on these old trucks. Its got new plugs, cap, rotor and wires. I checked the timing again and I got it set at 12 degrees at 800 rpm with distributor advance disconnected and vacuum plugged. It has a manual fuel pump. Fuel filter is on the carb. So waht are your thoughts??? I am kinda at a loss.

[Hardcore-CashMoney]

So not sure what is going on. Thinking its carb related. Suburban was running fine, although always seemed to be a bit sluggish. Then last weekend took it out in the desert and was climbing a hill it lost power and died...got it started back up but it acted like it needed to clean out. Lots of black smoke. So I drove it home, never could get it over 20. Sometimes if I was sitting at idle reving it up you could here a change in the sound and the thing would clean out, no more black smoke and sound good. Soon as I put it in gear and got about 30 feet it acted like it loaded up again and would get real sluggish. I think its a carb problem. Standard Rochester 4 barrel carb that came on these old trucks. Its got new plugs, cap, rotor and wires. I checked the timing again and I got it set at 12 degrees at 800 rpm with distributor advance disconnected and vacuum plugged. It has a manual fuel pump. Fuel filter is on the carb. So waht are your thoughts??? I am kinda at a loss.

check the floats yet? maybe they stuck open.

[WILLD420]

Vacuum advance, or ignition module. I'd go ignition module first, then check the vacuum advance while I was in there.

[rusty_tlc]

Quick and dirty you could try hosing it down with carb cleaner and see if that helps.

[BIG BLUE]

I need to drop the tank and flush it. It really seems to run bad at the bottom of the tank. Also It goes thru gas fast. I need to pull the carb apart and check thru everything. Its the stock carb but it really seems to just be flooding the engine.

[Brizzman]

I've still got that other carb if you want to try that.

[BIG BLUE]

I've still got that other carb if you want to try that.

I sure would like to give it a try. All my electrical brand new...wires, cap, rotor, coil, plugs...and it still does the same thing. I did find a issue with the carb and fixed that but it still acts like its loading up..so I would like to swap on a known good carb. thanks

[Brizzman]

You can come and get this one to try out. It probably won't run as well as the one you have. The jetting will probably be different. If you know what the jetting on yours is, I can probably get it close. Or we can change over the jets from yours. I've gotten so I can rejet it in less than a half hour, after working to get the FJ to pass smog. :rolleyes:

[BIG BLUE]

so someone help me out here. When I time it to 8 degrees it runs like crap. So out of frustration i just kinda bummed the distributor up and all of a sudden the engine smoothed out...like 20 degrees...with vacuum advanced hooked back up it sits at 45 degrees, and runs good and has power. It still kind stumbles but that cause the carb needs a rebuild. Now from what I was told this came a racecar..is it possible that they didnt set the timing chain at zero?