View Full Version : Engine stumbling bad
67_RS Feb 26th, 01, 11:05 AM I have a 67 with a 327 and four speed. It isn't stock but is built for street use, it has a 650 or 600 holley spreadbore, double pumper with mech. secondaries. It has a elec. fuel pump at the tank, and is running factory points. Before the restoration it ran strong the little bit I drove it, but I didn't go very far. Last summer I moved it from one shop to another, and found a problem, after two miles it starts to stumble, after I get on it a bit, then it doesn't seem to improve and gets worse. Thought it might of been the fuel reg. being set at 3 psi. Last week drove it home, and it did the same thing. Drove a mile at 25-35 mph, no problem, then got on it a bit in 1, 2, and abit into 3 it fell on its face, and the next mile home it barely ran. Had to baby it and coast into the driveway. I am thinking either bad ignition, have petronix setup to put on, or bad fuel pump. I am going to put the ignition in, but how should I check the pump, how much fuel should I have flowing at the carb if I unhook the line and run into a can, and can that cause the problem, I would of thought that the pump would of caught back up and it would of at least ran decent if I babied it. When I got in the driveway I restarted it, had to hold accelerator to floor, then it started, but idled great, revs fine and everything. Am holding out on checking the fuel flow, because it is snowing out, and I can't get gasoline smell in the garage, I will get shot for that. But I can pull the distributer and put the ignition in, want to get rid of the points. Also, I dropped the tank a few weeks ago and pumped the four gallons of gas that I had put into it back into the gas can. I unhooked the line by the pump and pumped straight into the can, seemed a bit slow. Seemed to be a even flow, but not any faster than if it had been gravity fed. It is a diaphram pump and it does pump up and stop like it should, but it could still be weak. Any suggestions would be great.. thanks
ilbl8 Feb 26th, 01, 12:41 PM check simple thing's first, plug's,wire's, cap/rotor, point's/condenser, fule filter, water traped in the gas from siting, summer gas in the winter...old stale gas.
i bet you just need a good tune up, and some fresh gas and a fuel filter.
[This message has been edited by ilbl8 (edited 02-26-2001).]
67_RS Feb 26th, 01, 01:24 PM I just put in the pertronix, and the points looked good. I didn't figure they were bad since it started and idled fine. The cap and rotor still look like new, they don't have any road time on them. I rebuilt the carb last winter. New fuel filter, I did just notice that I had the regulator at 3.5, I turned it up to 6. But when I did that this summer it still didn't help. I still want to check fuel flow at the carb but can't do it in the garage, and if I back it outside I will have major problems, can hardly walk it is so icy, rained yesterday and it is 15 degrees today. Also has any one had a motor with blow by out the breater from sitting and not being run much?? Will it get better, this motor has no miles on the rebuild, and was built with quality parts. The guy I bought it from used to bracket race and the short block is blueprinted and balanced. Also the gas is all new, and is winter gas, only it is 87 octane, it does ping some, forgot to get 93. Will take care of that before i drive it again.
[This message has been edited by 67_RS (edited 02-26-2001).]
mccorry Feb 26th, 01, 03:23 PM May want to check your dwell angle also...
camaroguy Feb 26th, 01, 05:40 PM Check your float level in the Holley by removing the brass screw on the side. It should just barely dribble. Also, if the carburator backfired on you, it might have a blown power valve.
dale68z Feb 26th, 01, 07:24 PM If you take the fuel hose off at carb,there should be a good shot of fuel into a coffee can.Probably put out an inch or so of fuel in can,in 30 seconds.Should not be bubbly.At idle,should have 6# of pressure.
------------------
68 z28 ,68 rs 327 ,73 454 vette, 2 goofy kids
67_RS Feb 27th, 01, 03:58 AM I have the Petronix in now so that should take care of the dwell if that was the problem. If it was a blown power valve I would think it would run bad right away. The way it is acting it runs fine for a mile or so, then starts acting up. I will check the float levels, and I want to check the fuel flow with a can, just can't take the car outside, afraid it will slide into the garage door trying to get back in. Don't want to put a dent in it now, after all the work done to it just because of some ice.
67_RS Feb 27th, 01, 08:57 AM I think I might of found the problem, I just checked the gas flow to the carb. I hardly got a dribble, then I turned the reg up to 6 psi, and it flowed full flow. I think I may of had the regulater turned down too far is all. Will have to wait and see if that was the problem. Thanks for the input. On the holley carb I have you can't check the float levels, there are no plugs to take out.
|