The Stovebolt Site Forums The Shop Area Engine Shop Carb, points, or ??? Stalling while driving

After stalking, searching, and generally benefiting from the wisdom of all you folks on here, I've finally had to join and post because I couldn't find what I was looking for.
Purchased a '61 Apache 10 with 235 in it. Got it running and looking decent, decided to go fill it with gas instead of going and filling the gas can. Took me 1.5 hours to make the 9 miles round trip... :ohwell:

The truck would do this: cruising down the road and suddenly start bucking and then the engine would eventually die, first leg made it almost 4 miles, after that it wouldn't make it more than half a mile at a time. If I keep the gas in it'll buck violently for a little while longer and then die. I searched through the carb threads because it kind of sounded to me like its flooding itself out, lo and behold my truck has a Rochester Monojet on it from a 69 Buick 250.

Found a Carter W-1 for $10 and then went and talked to local carb guy about getting a rebuild kit for it. Said Carters were junk and the Rochester (even though its the wrong one) would be better to just rebuild. Well I took it apart and cleaned out some gunk and its still doing its stall and die thing about 1 mile down the road (haven't gotten more than 1 mile legs out of it since the initial gas station first leg of 4 miles ish)

Read another post on here about points being bad and not working when hot. Not sure how I'd check that.

Also, on a separate note my profile wouldn't let me put in a sig, said it was too long even if it was only 2 letters so here it is: 1961 Chevy Apache 10, 235, 3 on the tree.

You can't add a sig because you're still in moderation. After 4 approved posts, it will work.

It could be flooding. Or it could be starving for gas. Check the gas filter. Is it plugged up or restricted real bad?

The Rochester Monojet is a good carb. Don't konw about Carters.

You didn't mention it, but if you have to sit for a while and then it restarts, it could be vapor locking. Make sure none of the fuel lines are touching anything that get's hot (motor, head, upper water hose housing, etc.) There's a reason they put standoffs on those lines to hold them away from heat.

I doubt it's the points, but it might be. Usually gradually deteriorating performance is fuel related though.

May be to much fuel pressure, i added a Napa inline fuel filter and set it at about 2lbs or less, problem solved. Good luck

The first time it happened I let it set for a while because I thought it might be overheating and my gauge was lying. But no boil over so after that time I could just start it again after a few cranks it kicked over. The fuel filter is fairly new and doesn't look all gunked up and is always has fuel in it every time I jump out and open the hood.

For the vacuum advance on the carb: is it supposed to turn the distributor as soon as it gets any vacuum? Mine will immediately turn the distributor as soon as I hook the vacuum to the carb while its idling. My carb experience is limited to my old motorcycles.

I'll see if I can get one of those NAPA filters and limit the pressure to the carb. I did read about that on one of my searches.

So no one sees any real problem keeping the monojet on there? And the Carter I have is the wrong size anyways so if anyone wants a beat up 41-48 Carter W1 let me know. JiMerit did you use a specific filter or just any with a pressure reducer?

Thanks for the help so far.

I would check fuel pressure, either it's starved or it's over powering the needle and seat. Start it up and look into the carb at idle. Look for fuel free flowing, also with it off crank it wide open make sure it dumps fuel. Quick easy checks. Also the fuel could be boiling off like stated previously. Check the lines and check the filter. Best of luck to ya.

Well I'm guessing here: You got it running static, no load. Then took off down the road? I will say fuel pump is going out. I would at least confirm with a flow test before proceeding.

Been there and done that. Start with one thing at a time. If that truck sat for some time then fuel would be as good a place to start as any other. Sounds like you have spark and compression so those are off the table for a bit. Old fuel and new fuel are not friendly mixers. New fuel will sorta dissolve the residue from old fuel. That makes for a sticky and often gritty mix. Quick and dirty fix? One fuel filter between tank and fuel pump. Second fuel filter between pump and Carb. Test drive. One down and more to come...:) Pull the line from the pump to the Carb. Put a catch can under it and see what the pump is doing. Got fuel;? Good. Don't? Change the pump. Pesky problems are sure to follow. But with the filters in place at least you won't hurt the pump or the Carb kit you just put in, that is good. If you were so unlucky as to get something like I did you will have a clogged fuel line from the tank to the pump. Quick fix? Roll a bit of fine metal screen about 3 inches long and push it into the tank outlet right at the tank, if you have the line from the bottom of the tank. If you have the line from the top of the tank then you might have to pull the sender out to clear it. Pull the line off the tank and the pump and push some air through it. Got fuel and still got issues? Time to check that the needle and seat in the Carb are not stuck. Are you having fun yet? I went through all of this and then my points lost the rubbing block in an intersection. Still the most fun thing to drive ever! You will get it sorted, you will.

I would take a broom handle and use some duct tape to hold it on the stick good. Then stick it in the tank and rub it across the bottom of the tank and pull it out. If it shows mud/rust/dirt you should either replace the tank or have it cleaned.

Are you runnimg a stock gas cap?

As others have mentioned, this is probably a fuel related problem. If the truck has sat without running for some time, the fuel has probably gone bad.

Where to start?

Can you disconnect the fuel line from the tank to the fuel pump, and then connect the fuel pump to an external tank (possibly a portable marine outboard tank) with new fuel, and also change the fuel filter? This would test whether the fuel pump is OK.

My GUESS would be draining and flushing the fuel tank, and replacing the fuel filter would go a long ways to solving your problem.

As to the argument on Rochester vs Carter, lots of pixels on the internet have been disturbed on this subject; but we SELL Carters and GIVE AWAY Rochester 1-barrels. That should explain our stand on the issue:

http://www.thecarburetorshop.com/Free_carbs.htm

In your case, I doubt either the carb or the ignition are at fault.

Jon.

As others have mentioned, fuel problem. If the truck has set for a while the tank could easily have crud in it clogging the fuel line. When it is under load it will eventually clog enough to stall. Then it sits for a few minutes and will start up because the pressure has released the crud from the line allowing fuel to refill the carb. Clean the tank, blow out all the lines, put in a filter before the pump and another before the carb and try again.

If you keep do have bad gas and a dirty tank and continue to run it plan on fixing bent pushrods and stuck valves. That is the biggest problem getting something going that has sat for a period of time.

Couple questions:

As mentioned above, will the truck run idle without issues?

Is there any backfiring from the tailpipe or carb?

Taking the fuel line off at the carb will test fuel flow. As mentioned above, if it will run without load then acts like a mad child on the road it could be vacuum advance not working or fouled points.

Two simple test. Sitting idle, stand on the passenger side of the truck and have someone goose the gas. Watch your distributor, as the throttle is pressed, the distributor should rotate. If not, bad vacuum advance.

Second test is to remove distributor and look at the surface of the points. If they are not smooth and shiny, that could be the issue also.

Good luck!

When I picked up the truck I drained all the old fuel and the lines even though the guy promised he had stabil in it. The sock filter on the sending unit looks clean and there actually wasn't much junk to see in the tank, the carb will squirt after shut off and throttle is moved. Stock gas cap yes but there is a gap in the filter house that ensures no vapor lock there. I'll double check fuel lines close to heat again and there is definitely plenty of pressure when idling on the fuel supply line when I took it off the carb. :) No backfiring or black oily exhaust, and it'll idle forever.

Thanks for all the replies, have some checking to do after I fix the fence the wind tore up.

Josh

Also, I ran the carb off a funnel of fuel to redo the pump test a little better, it comes out pretty quick right after I take the pliers off the hose, but then slows to a very slow trickle, used a pint jar as a catch can and it took about 4-5 minutes to fill does that sound right? Don't have a pressure gauge.

It should fill a pint jar in less than 30 seconds.

That explains a lot. Over time the gas flow is slowing down dramatically. Thus the bucking and dying. The question is why. Assuming the lines are clear (and if they weren't, the flow would be steadily slow not increasingly slow), there are only three possibilities I can think of; fuel filter, fuel pump or sending unit.

A filter can fill up with trash and slow the flow to a trickle. Then, when the flow stops, the trash settles, and the flow will be fine for a little while after it first restarts.

Take the fuel line off the inlet side of the fuel filter and rerun your test. Does it still take as long to fill a pint? Then the problem isn't the fuel filter. If it fills fast, replace the fuel filter, but keep in mind that something is plugging it up.

Old vehicles get varnish in the fuel tank and the lines. Unless all of that is thoroughly cleaned out (or the parts are replaced), the varnish will continue to break loose and plug the filter. (Varnish can also screw up a fuel pump.)

If it's not the fuel filter, you've isolated the problem to the fuel pump and the sending unit, remove the line from the sending unit and put it in a container filled with gas. Repeat the test. If the pint fills fast, it's the sending unit or the tank itself. It it doesn't, it's the fuel pump.

If funnel of fuel means a gas can, or equivalent, hosed right to fuel pump inlet, then it's the pump. But I don't get what you actually did? If you did not do that, use a clean rubber hose from pump inlet to a gas can and do test. Bypass all the existing tubing, hoses and filters leading to and from pump. On the outlet side of pump, don't go thru any filters or bad lines into test jar. Then your pump test is pure. You gotta eliminate the pump as the cause before you do anything else. Your test shows BAD PUMP SO FAR. One more time the pure way. If you have a good battery or jump, disconnect main dizzy wire while cranking/filling jar. Pump should surge gas and fill pretty quick, no misses in the surging.
As for carburetors: It's like Ford and Chevy, there are many good one's of each. It depends on the year, model and a bad experiences. I.E. in my experience, The Carter AFB, (Edelbrock) is easy to rebuild and a good carb. The Quadrajet is a good carb also, I have rebuilt many. Carbking knows about carbs and especially old carbs. Do what he says, but later. I'm sure he will take your W-1.

I tied a funnel to the hood while it's up and gravity feed the carb through new fuel hose to keep bowl full and engine running. Disconnected just after the filter and (while engine running) used catch can. So everything from tank to just prior to carb was all normal. I just installed a 12v pump on there now back by the tank still seems to not have much fuel supply. (New filter before pump and new one before carb. I bypassed the mech pump. So I'll have to open the gas tank and check that more thoroughly. Maybe the sending unit picked something up.

I'm totally lost.

Did you check the fuel lines?

I have had a piece of rust the size of a dot cause the fuel pump to quit working, it takes very little to stick one of those little valves in there.

When it 'bucks and stumbles' is there black soot smoke from the exhaust?
If yes, then you are getting raw fuel into the engine, likely overly high fuel pressure or needle & seat.
If no, then you are not getting enough fuel thru the carb for many different reasons all of which will be solved with a good rebuild.
It might be ignition, the carb gets blamed for ignition problems and the ignition gets blamed for carb problems - I just don't think so in your case.

No black sooty exhaust. The sock filter had some sort of fine sediment in it. Must have gotten a think coating of dust somehow on the tank and then when I filled it more than the 2 gallons at a time I'd been doing it sucked it all up. Time to drain the tank I suppose... So now I have an electric fuel pump though. I think the mech pump is fine, is there any problem with running them in parallel? Or will that probably overpressure the carb? Guess I should listen to my elders and check the dang fuel tank and lines! Haha, but thank you all for the help and I'll let you know when she is carrying me to work every day.

JB

ha ha what a troubleshooting recommendation! very funny!

Pumps in parallel? are you sure? I am thinking series, one ahead of the other? but why? Just use one or the other! not two. Remember, if you have crap in the tank, you have crap in the gas, in the pump, and in the carburetor and it shows in the filter if you have one installed. Most old gas tanks will deteriorate and give up their galvanized surface after say 20-30 years. Cleaning and treating tanks that have started to deteriorate is a waste of time and money. Take several fuel samples out of the bottom of the tank at the fuel line using a clear glass jar. Inspect the sample for rust flakes, black specks (galvanized material), dirt, or other crap. Fuel should be clean, clear with only a slight color with NO TRASH or water (which will settle at the bottom of the glass jar). If anything like this is present, replace the tank, clear the fuel lines, change fuel filter, and clean the pump, and carburetor fuel bowl and needle valve and seat. I would suspect you have a FUEL TRASH PROBLEM caused by a deterioated tank.