I have a 1977 ranger 351m.I have put 4 reman on it in two weeks.Now it's a little better,but at high rmp or just a long idle it will bog down and blow black smoke for just a second or two then it will clear up for a will.I need help............

 

Almost sounds like a valve or spark problem, perhaps some more specifics on the carbs and engine?

 

the carbs are the 2150 motorcraft.The plugs are just run of the mill plugs.Some one told me to run hotter plugs.What's that mean and what ones should I buy?

 

Test the ignition modules at a parts store. It sounds like something other than the carb if you have tried 4. It also sounds like you have a nice parts store to just keep giving you carbs.

 

Already replaced those.I think it is the choke

 

Where is the timing set? Does it do this all the time? Is it cold where you are? Is the vaccum advance hooked up?

If you post some more info and I can help more.
-Brents

 

starts good hot,like crap cold,intil you take off air filter and open the flap a little.I just had it timed 3weeks ago.It was too far advanced.The vaccum advanced is hooked up. Thanks for the help.I can use all the help I can get.lol!!

 

Does this only happen when you try to accelerate? Or is it ok at a steady speed?

If it bogs when you step on the gas, I would look at the accelerator pump circuit (with the arm that goes to the lever on the front of the carb.) It puts a squirt of fuel into the carb when the accelerator is pushed. It can be adjusted to provide a not-so-strong shot of fuel. This will help with the bog issue.

If it does this at steady-state, I would look to see how the choke is operating. Does it have a stat coil that has a wire connected to it? Does it have a heater tube plumbed into it? It needs both those items to have the choke heat up and pull off correctly, in the correct amount of time. These items are on the left hand side of the carb when you are standing at the front of the truck looking at the carb.

Post some more and we can work towards narrowing down the problem.

-Brent

 

it only happens when you try to give it gas all at once.At a steady 55m.p.h. it drives like a dream.If you floor it from a dead stop it likes to bog down,then you have to feather the gas to keep it running.It does have the heat thing plumbed into it.It does'nt get real hot.

 

hmm id look into timing again, but accelerator pump for sure, I had that problem a few years back

 

Why didn't you just set the choke on the original reman carb rather than replacing it 4 times? You do have to adjust any replacement carb, they are just set up to be in the ballpark to get it started.

 

The other reman were junk. One leeked out of the accelerator pump,one had bad floots in it from day one,the other the butterfly flap would not even move!So I did not adjust a broken carb.

 

AHA! It kind of sounded like you had the same problem with all four carbs.

 

This sounds like your choke is not setup properly. Is the choke opening at all? Once you get the truck started and warmed up, verify that the choke plate is swinging open all of the way. If not, adjust the choke per the manual.

Black smoke always means too rich a mixture. that either means that the truck is running too rich constantly and when you goose the throttle, you are blowing out the buildup or like was said earlier, the accelerator pump is pushing too much fuel into the engine. I am betting on choke since what you describe sounds like a partially choked motor.

Had a 1971 240Z that ran rich and would foul plugs all the time and ran like crap when it did.

One more thing though... Make sure that your plug wires are in good shape. A partially firing plug will foul out really bad, especially when the mixture is too rich. Even if your wires LOOK good, if they are too old, they might be going bad. Make sure that your ignition system is up to snuff and then make sure that you have adjusted that choke properly.

A hotter plug won't do the trick if you have a bad cable and if you think about it, your truck ran great when new so changing plugs to a hotter range is going to be a bandaid for something else that is still not right!

John Neary

 

OK, to me, it sounds like you could use a little more initial timing, to do this you need to move the distributor to the left a little bit (when standing at the front of the truck looking at the distributor). You'll need to loosen the dist. hold down bolt. You may also want to mark (with a marker) where the dist. is set before you start your adjustment. Don't move it alot, mabey 3/8". My truck with this motor really likes lots of initial timing. Runs great with a little extra, runs like crap when set where the factory says.

Second thing I would do it lean out the accelerator pump cicuit by moving the lever rod such that it provides a smaller squirt of fuel when you step on the gas. I can't remember which way to move the rod, but if you look at it while moving the throttle linkage it's not too hard to see how it works.

Post back and let me know how you make out.

-Brent