78 Bronco

[marvin]

i just got this 78 it's in real good shape NO rust but it was in need of a tune up so i did the normal stuff and it runs much better the only thing is it bogs on take off if i give just a bit of gas and then lay into it's fine but if i just lay into from the start it bogs could it be the auto choke ??? it opens fine but i'm not sure i'm trying to spend as little as posable the wife is already on me about the $$$ i have spent and i'm about to go spend some big bucks on tires it is in bad need of new ones and off the subject for a sec will 33's work on an 78 without a lift for normal driving untill i get a lift ??? if not i'll have to catch the 33's next go around

but the bog on start is killing me i need to get it fixed also i have a exhaust leak could that be it ?? it's near the manifold just an idea but any help would be very helpful it has the 400 if that helps

 

[4xfan78]

What size tires are on it now? Do you have cats. on it? If you have over size tires on it and stock gears in the rearend that could cause it. If the cats are old that could cause a restrection in the exhaust system which could give you that problem.

 

[marvin]

it has 31's atm no cats but like i said it has a pretty good leak i think that is it i have checked everything i can think of but any ideas are helpful thanks for the reply /emoticons/[email protected] 2x" width="20" height="20" />

 

[Broncoholics]

The exhaust leak shouldn't be a problem for a bogg down. I had a Holley Carb and it only ran well if I floored it after time, otherwise it would bogg down like you are saying. I switched to a Carter Carb and it fired right up, passed emmissions and worked well without ever tunning it. :lol: But you might replace the fuel filters first. You could have one on the carb as well as the frame rail.

Another idea is fuel pump or even crap in the tank. When I pulled my tank it had sticks, pieces of plastic, sand and a few small rocks.

Do you have points or electronic ignition?

 

[davids78bronco]

Transmission:

Check the adjustment of your shifter linkage

Check/replace the vacuum modulator

Change the trans fluid and filter

Make sure it has the proper amount of fluid, and that it isn't burnt

Exhaust:

pull the exhaust manifolds, and check them for cracks

While the manifolds are off, you'll have to replace the gaskets anyway - you don't need solid copper gaskets, but copper-cored gaskets would be a good choice

 

[highboy73]

make sure the motor is not running ,pop your hood,take off your air cleaner look down inside of your carb you may have to manually hold the choke open,while looking down inside the carb push the linkage like you were giving it gas,did you see a steady stream of gas?no,it's the accelerator pump under the carb,yes it did have a good stream check your timing,don't set it by ear get a timing light.if you get a chance and have the money get the dis. recurved and a cam.make sure you by the timing chain set that has the timing line up dot above the keyway for the woodruff key on the crank.

 

[highboy73]

oh yeah the tires should fit.they did on my stocker with stocker wheels

 

[asemaster tech]

Check the vacuum to the distributor if the vacuum goes through a ported vacuum switch. It could be bad causing the advance to be getting the wrong vacuum. Having ported when it is supposed to have manifold will cause that.

 

[Guest]

CHECK THE TIMING SOMETIMES AS THE ENGINE WEARS THE TIMING WILL CHANGE SO IF YOU SET IT LIKE THE BOOK SAYS IT WILL NOT RUN CORRECT. HAD ONE DO THAT TO ME TURNED OUT THAT THEY HAD REPLACED THE TIMING CHAIN AND MISSED A TOOTH SO WHEN THEY SET IT ACCORDING TO THE BOOK IT RAN LIKE*@#$!%.

 

[Ziggy]

What carb do you have on your engine? If it is the original 2 BBL (Holley 2150), it sounds like your "power enrichment valve" is bad. A sure sign that it is bad is that the engine floods out on accelleration, such as bogging out on take off. These go bad for a couple of reasons, the main one being back fire. The valve can be changed and will run you about $5.00-$7.00. The valve is located on the front of the carb, bottom of the float bowl. Look for a small cover held on by 3 small screws, remove the screws (after pulling the carb), remove the power valve and replace with a new one.

 

[highboy73]

i hope he fixed it by now

 

[Billz4x4z]

The type of bog your describing,and how you slowly can power into it sounds like a bad accelerator pump on the carb,which is just a 5.00 fix and about 10 minutes of work.

 

[davids78bronco]

i hope he fixed it by now

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Considering this was dated back in August, I would hope so too!

 

[marvin]

sorry but yes it's fixed it was the timing chain