bucking, bogging out and dying under load or high revs

[sizod]

So of course since its the coldest day its been this winter, the truck 73 series III decides to have problems, I had the car "serviced" by a reputable british car shop, and a day later this issue pops up. They did a fluid change and adjusted the valves, normally i would do it, but i was going on vacation and I needed an inspection.

The truck seems to be lacking its normal power, it struggles going up hill, eventually it bogs out, bucks and dies. the same on the flat if 1st and 2nd its fine, I can drive and rev it all the way up, when I shift into 3rd its fine but as i get to the top end of revs its starts to die and buck.

Fuel starvation? air leak? they didn't adjust the timing and I think richened the mixture by a 1/2 turn What are your thoughts..

Thanks

-s

[busboy]

I would check the vacuum source going to the vacuum advance on the distributor, if that's ok then check the point gap. Next pull the plugs and check to see what's happening.

[SafeAirOne]

That happened to me (again) just yesterday--14 degrees outside. Lovely.

I'd check the sediment screen on the bottom of your fuel pickup tube in the fuel tank. The more it gets clogged up, the less fuel can be supplied to the engine. As you continue to drive, you'll loose the hill climbing power first, then high RPM no load power then it'll continue to deteriorate as you build up a fuel deficit till the engine won't even idle anymore.

Often, if you park it and let it sit a few hours, the suction that's built up in the fuel lines will suck enough fuel through the lines from the tank that you can start up and go through the whole thing again!

This also goes for any clogged fuel filter you may have in the system, usually prior to the fuel pump.

There's a pretty good chance this is the culprit, based on the description of your problem, however, being a petrol engine, it could also be a couple of other things.

[sizod]

Thanks.. I have the the pertronix electronic ignition mod on the truck. I'll test the vacuum advance on it in the AM.

[sizod]

Thanks Mark.

I replaced the tank a couple of summers ago and the sediment looked clear, I have one of the proline fuel pump (which are garbage IMHO) bought it 2 years ago and had to rebuild it twice as both proline diaphragm's failed.. I'll double check the pickup pipe and the fuel filter.

Looks like another freezing morning of car maintenance.

[Manny]

Make sure all the vacuum hoses are snug. I had the same problem with mine and it was a vacuum hose at the carb

[stomper]

Also, since it is occuring in very cold weather, are you sure you don't have some ice clogging up the fuel filter? How old it the fuel, and did you get it from a decent gas station? It might be worth a shot to pour a little fuel conditioner into the tank to absorb any water in there.

[rickv100]

I also think it is bad gas causing clogs in the fuel system. I got a tank of bad gas(high ethanol content)s which caused a grey sluge to clog the fuel filter ahead of the carb.

Rick

[sizod]

Update. I'm freezing!!!!!!

truck is running, seems to be ok. Here is what I did. pulled out the pick up tube. It looked clean, gave it a swirl around in some gas, no real crude or clangers came out. sediment bowl. That was clean and clear. up to the fuel filter, replaced it with a new universal glass one, from Pep boys and 2 new 3" sections of fuel line before and after the filter.

I also test the vacuum advance with a vacuum pump and that seemed to be ok. Then went around and tightened everything up.

Truck seems to be running.... was it the fuel filter? or made a stuck vacuum advance? I hope it was just a fuel filter, either way pretty disappointed that replacing the fuel filter wouldn't be part of an service and tune up. Should I done it myself, I need to build a garage, outside winter mechanics is brutal.

Thanks to everyone for the help!

[SafeAirOne]

I'd still drive it around for a while, then climb some hills or do something requiring lots of power to make sure you can't reproduce the problem.

[gudjeon]

Drive it for a bit. Keep an eye on it. Mine did this for a year before the fuel pump packed it in. It would have been easier if it just packed it in all at once.

[singingcamel]

Sometimes buy just tightening things up will the draw of unwanted air leaks into the fuel system, especially the base of the carb.

[Dietersrover]

You know the old saying, " Timing is everything". I would check the timing make sure the distributor did not move.
I would also check the ignition coil and the wire going to it.