Engine dies during acceleration

[logic2]

I'm buying a 1971 fj40 with known mechanical problems -
Stock F155 engine that does not knock or smoke, it ides ok and starts good, etc...

I am being told that it dies (or almost dies - runs really, really rough) under acceleration. Running it slow down the road seems to be ok, but when you press down on the accelerator (mid-range for example) it bogs down and almost dies.

Any ideas -
Vacuum advance ?
Distributor ?
Carb ?

Thanks
Mike@logic2.com

 

[hammerhead]

I've seen plugged fuel filters or bad fuel pumps act the same way. Enough fuel gets through to idle but the increased consumption of acceleration runs the fuel level in the carb too low causing starvation. Change the filter/s. Next would be fuel pump if that doesn't fix it.

 

[jungleboy]

had the same problem but with the 2f. also when I had to go uphill it was a real pain. Thought it was carb...ended up the cable that runs from the coil to the distributer was no good. changed it and it now runs like new

 

[VehiculousFJ]

Had the same problem here. Went through 2 carbs, about 7 rednecks, distributer, coil, wires, and ultamtely accidentaly ended up chipping the tip of my crank off.

 

[Jukelemon]

If it has "known mech issues", that is probably a sign that preventative maintenance was not done. In other words, it is often the case that if someone is selling a vehicle when it has issues, that person probably bought the car with 0 issues and then ran it until there were problems. Just my .02. But on that logic, you need to go through everything having to do with general maintenance i.e. plug wires, coil wires, plugs, air cleaner, all filters, all fluids (will not fix your issue here but should be done nonetheless). I would dismantle the carb and clean it with carb cleaner and a compressor. If you do not have a compressor, go to Staples or Office depot and get some compressed air for computer cleaning (looks like a wd-40 can). With the carb out, start the vehicle and see if your fuel pump is sending fuel at a good rate. The symptom you describe can be many many things. Can be not enough fuel due to a bad fuel filter, fuel pump or incorrect float setting in the carb. Could be a clogged jet or fuel passage.

Point being, do some cleaning and basic replacement and see what happens from there. If it is still there, then that throws out A LOT of assumptions/guesswork. And no I do not mean buy a new carb, new coil. I mean start with the small stuff like filters and cleaning.

Good Luck.

 

[airon23]

Just to echo the others start with the fuel filter and go from there. If you've already bought it do all maintenance stated above. Will help greatly.
Good luck on it.