Inliners International Forums General Discussion Engines Engine "pops" misses when warmed up? Carb?

My 235 has new points, plugs, etc. Was running great for awhile. Now it "pops" and misses when idling... seems to be running a little rich too... why would this start all of the sudden? Carb possibly?

Thx.

tough to say without being there.

Was it fine before you tuned it up?

Did you do anything besides the ignition?

Have you re-checked the dwell?

Actually I converted it from 6 volt to 12 volt. After I did that it has run great going on 3 months. I replaced the carb at that time too with a manual choke version and it ran much better than with the old carb (faulty auto choke).

I'm going to pull the carb and clean it out, check the timing again, and try and see what's up.

Thx.

Did you install a resistor on the coil when you converted to 12 volts? if not you may need a new set of points.

Ahhhhhh.... that may be my problem! How does the resistor hook up? I don't think I added one. I'll order one of those and a new set of points while I'm at it.

Much thanks!

It goes in the hot lead to the coil from the key. The ones I have seen are a ceramic affair with two spades (male) sticking out one side and the resistance element visible on the other (kinda looks like a small heating element coiled around a rod, but it shouldn't glow like a heating element). On this end of the planet the parts stores like to call them a ballast resistor, I'm sure there are other names, but maybe that will help, I hope.

Ballast resistor is the most common name for them. GM used them in 1955-1957 and Chrysler used them for a lot of later years. Your local parts store should be able to fix you up no problem.

You should be able to buy a ballast resistor at any parts store also you can purchase a 12 volt coil with a built in resistor either one will solve your problem if the miss is caused by the points being toast.

Well now, when I bought this coil they said I didn't need a separate resistor.... How can you tell if what you have it correct and a resistor isn't needed?

If you are burning up points on a regular bases then you probably need a resistor, if not you are ok. Was your points wiped out & if so did a new set solve your problem?
A six volt coil won't need a resistor running on six volts but if you convert to 12 it has to have a resistor. Another thing that will burn up a set of points is leaving the key on for an extended period of time with the engine not running.

If you use a voltmeter after installing the ballast resistor you will find about 7 to 9 volts. This is not enough to burn points. Your starter solenoid probably has the 2 connections. Some have converted them to the 3 connections which will give you a "hot start" meaning 12 volts go to the points and coil on statup only when the solenoid is energized. Most of these cars did not have the ballast resistor but resistor wiring from the ignition switch so when the key went from start to run the voltage dropped. If you ever put on an HEI remember to remove the resistor wire or ballast resistor.........Good Luck..JD

On newer coils, they print right on the side of it whether or not it needs a resistor.

It was converted to 12 volt.. so I guess that pretty much answers that question. Thanks!

Ok.. I checked the coil and it has printed right on it that it doesn't require an external resistor. I checked the points and they look good too. So I'm pulling the carb thinking that it may be gunked up. Of course now the gasket is destroyed so I've got one on order. This waiting game is killin' me.

Another thing, since you are playing with the carb, there is a hole in the base of the carb. This hole requires a vac signal in order to operate the power circuit properly. If your carb base gasket is blocking this off, it may be adding to your problems. Modify or replace the gasket as needed to correct this issue.

Well it's not the coil, not the points, cleaned the carb, still has the same problem.... hmmmmmmm.

Why would this just start happening all of the sudden?

I noticed the plastic base of my air cleaner adapter is broken and missing a couple pieces...I really hope nothing got sucked into the engine.. ugh.

You said you rebuilt the carb. Thats why I mentioned it.

Well I did a full tune up replacing everything. Tried starting it and with one final delayed (and very loud) bang... it's now officially dead. Won't even fire up. I'm getting my gun out!

Where can I get a good layout for my plug wire routing? I don't think I have anything cross-wired, but want to make sure. My "detailed" manual doesn't seem to have it!