carb or fuel probs?

Question

i have a international 1210 4x4 with a 392 and it cuts out at around 55-65 mph on the highway ive checked the float levels and there fine but i cant figure out why it wants to die out like its getting no gas please help if you can

lets try again im running a holley 600 cfm vacum secondaries and about 8.5 lbs of pressure in the fuel line at the carb inlet its got a liquid filled gauge thats how i know and if i didnt know how to adjust my float level i think i would have put that into my question so i know its done properly. i just cant figure out if ive dropped a power valve or if something else has gone bad with out buying a new carb or buying a bunch of new parts for nothing

Answer 1

Check your fuel filter and/or fuel pump pressure.

Answer 2

How long have you been running this carb? From what you've given for info it sounds like this isn't something that was fine and then started acting up. Is this one of the universal Holley 600 carbs, model 1850? If it is and you recently put it on you have a lot of tuning to do, the universal carbs have a very crude calibration that doesn't work well for any application. A 392 needs a lot of fuel, the 600CFM rating is air flow and has nothing to do with air/fuel ratio so you probably need to rejet. You may also need to swap accelerator pump cams and secondary vac springs. Have you looked at the spark plugs? Every Holley I have seen is either too lean or way too rich. If the power valve went out there is a new design with a checkball to prevent future blowouts. Are you absolutely certain you aren't losing timing advance at that speed? The Edelbrock is a much better carb and easier to tune, throw the Holley in a pond.

Answer 3

What kind of carb do you have

I used to have a 400 Pontiac HP and the fuel ran out when we raced it.

You may need to buy a high performance pump or add larger fuel line,you should also check your fuel filter,it may be clogged
You can also check your lines for any that might be squished to restrict fuel

Answer 4

sounds like the diaphram might have a pinhole in it -(fuel pump) = that would cause it to starve during high fuel consumption but idle just fine. other causes might be vacuum leak, clogged fuel line, etc.

You say the float levels look fine - but i'm not totally convinced on that one - what carb?

Answer 5

sounds like a clogged filter check and see if you got a inline filter at the carb. If so remove it then test drive some filters can't tell if clogged by looking at them. Good luck