The Stovebolt Site Forums The Shop Area Engine Shop 235 Running rough

Help, my sweet running 235 has suddenly started running rough. It idles ok after it warms for a couple of minutes, but accelerating has a real roughness to it, like a cylinder is missing or something. I had just recently started using the old gas tank, and I have a good in line fuel filter just in front of the carb, so I don't think I've picked up dirt or rust flakes. I haven't yet put the resistor in the wire from the ignition to the coil. I am thinking the coil is getting hot, and breaking down and not giving its all to the points. This just happened overnight. The last time I ran it, it ran super smooth. Two days later, I started it and can barely keep it running. If I didn't know better, I'd swear I had one or two plug wires disconnected. Any ideas? Jim.

You could have dirt in the fuel clogging up the fuel pump. should have put a second filter before the pump. Are you getting any junk in the filter you have?

I'd take the fuel line off going into the fuel pump and drain some gas into a glass jar. Hold it up to the light and look to see if its full of junk. Then just set it on the bench for a while and come back and see if the bottom is full of muddy looking stuff. This should tell you if you have a fuel problem, then you can start with going through the fuel pump and carb.

I don't see any dirt in the filter and it is full. It wasn't always full before. I was running it with a rubber fuel hose sticking in a antifreeze jug full of fresh gas and the in-line filter never appeared full. Since it is full now, it would make you think that the inlet port of the carb might be clogged, OR it can't get enough pressure through the fuel pump to push what's in the full filter into the carb?

Could the points be getting burned by too much voltage? You say you have no resistor.

I cleaned the carb. The previous owner had the power piston spring in the wrong place. It runs better now, but not good. The resistor is hooked up now on the points, but the coil is still hot. The vacuum advance isn't right though. At idle, it is sucked all the way into the vacuum unit...which is correct (I think)...then, at acceleration, the vacuum drops thus letting the spring in the vacuum unit push the actuator out of the vacuum unit and thereby rotate the distributor clockwise giving the advance necessary for more power. Mine ain't advancing at all. I am thinking this is my problem. My unit never moves...even on acceleration. Any ideas?

It does sound like you need a new advance unit. When you snap the throttle, you should see the dizzy move a bit.
Chev's of the forties and other vendors sell these units.

Update: I found and fixed a lot of stuff but the bottom line is that it still isn't one bit better. The accelerator pedal return spring needed to be tightened up so that idle speed would always be constant. That made the vacuum advance start going all the way back...it didn't before. I also found the choke to be binding. The riveted shaft of the choke has a "C" clip that was bound up between the "ear" and the shaft, when it should have been a sixteenth of an inch over towards the fast idle cam to hold it in position. Once I fixed that (with the help of two pocket knives and the grace of God) the whole carb began to run better...at least on starting anyway. I also found the stem of the vacuum unit to be slighly bent. I fixed that and oiled it real good, so now the advance unit is working like it is supposed to...at idle, it is fully extended (making the distributor rotate clockwise). When the engine is accelerated, the vacuum pulls the stem in (rotating the distributor counterclockwise). It is working correctly although the motion of it is a little fluttery. It still acts like it is missing a plug wire though. Oh yeah, I reversed the leads on the resitor. I didn't think this would make a difference as far as the coil getting hot, but I think it may have...not sure though. The bottom line is, I fixed a lot of wrong stuff, but I still have a problem. I HATE to start replacing stuff, but I may put a new set of points and condenser in it tomight if I can find new ones locally. My FLAPS only had the Chinese version a month or so ago, and when I tried to put them in the first time. They wouldn't even fit on the post. After I reamed them to fit the post, they wouldn't adjust far enough to get the correct gap. I threw them in the trash can and cussed nafta and others. Anyway, I am hoping new points and condenser will solve the problem. The points and condenser that are in it now came from an old distributor I have had in my attic for 30 years. Tonight, I will also check the time with the timing ball. My timing light wouldn't work on the engine for some reason. I tried two different ones, but neither worked. If anybody has any ideas, I would sure appreciate the input. Thanks. Jim

Have you checked for a vacuum leak?

You know, I was noticing that the exhaust manifold was leaking a bit. I had put new gaskets on a few weeks ago and I think they have settled in. It would make sense that if the exhaust is leaking, the intake would too wouldn't it? Thanks for the tip. It won't cost a thing to tighten them again.
Jim

Fouled plugs from over choking is my "guess".

I went home for "lunch" and tightened the exhaust/intake manifold as tight as I could get it. It really helped. I think that was my problem. I squirted a little oil on the gaskets and could see it blowing bubbles out of the exhaust, so I tightened as much as I could. I figured maybe blue smoke would roll out the tailpipe if the intakes were sucking air, but none came out. I checked the timing with the ball as best I could. I was off a little, and I tweeked it. Sure wish my timing light would work on it. It's running pretty good now. Not perfect, but I can probably make it close when I can afford all new wires, cap, points, plugs, rotor and a new vacuum unit. Thanks to everyone who offered advice. I appreciated each and every post. Jim