Engine missing under load, hot start problems- two cylinders not sparking?

[Big_Guys_baby]

Hey Gang! I finally got the 46 on the road, and overall the clutch, brakes, and electrical work over the last year has worked out great. the issues I have been having have been an bad engine miss under load and some intermittent hot start issues. I inherited the car from my dad, and it just doesn't seem as zippy as it used to be.

At first I thought that It was due to some old gas still in the system, then I started thinking that it was the carb needing a rebuild or pehaps just needing to slap on an electric fuel pump.

Today it was particularly bad, after driving it last week, and couldn't make it out of the drive way. I pulled the spark plugs and saw that several looked clean, no carbon, but 2 looked terribly carbon fouled. Both are the the 3rd cylinder back on each side. 2 other looked partially fouled. Spark plug tester showed basically no spark at the cylinder for two cylinders.

Not sure what the next step is in finding out the problem? Any advice greatly appreciated.

[ken ct]

Many possible things. Dist,fuel pump weak,carb needs rebuild, Need more diagnostic work on your part to narrow things down to help out. ken ct.

[Big_Guys_baby]

Given that some of the plugs seem to be burning fine, but others aren't makes me think that it is ignition based. How can i narrow down wether the issue is fuel based or ignition based in this situation?

Although i know for fact the distributor has never been rebuilt. I probably should have sent it to bubba's when when the engine was out of the car, but i was over budget on the project at the time and just had to deal with what i had.

[Walt Dupont--Me.]

The first thing to do is take a compression test. It that checks out all right sent the dist to Babba, install a new set of plugs, I think you said you cleaned the carb and installed an electric pump. That should work alright. You should check the fuel pump pressure and the carb It shouldn't be over 3, You may have some sticking valves, if so put the marvel M oil to it. Walt

[jake197000]

how old are the plug wires? if the ignition stuff is old,coil wires etc.id replace them with quality stuff.have the coil rebuilt.pull dist and go through it.most carb problems are ignition related.

[Big_Guys_baby]

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Every inch of wiring is new on the car. The coil is a 6 volt aftermarket Napa style coil.

the car hasn't been driven steadily in over 10 years. I still have my notes from the last compression test from 3 years ago. Basically every cylinder got between 100 and 110 on the compression test.

I don't have an electric fuel pump yet. might put some marvels through regardless, i haven't done that yet. The hesitation on acceleration and under load "feels" like a carb accelerator pump but my instincts are driving me to think distributor. If no one else has any advice i might just go ahead and pull it off and send it to Bubba. I know that dist hasn't been rebuilt in the 40 years it had been around my family.

[Mike in AZ]

using the crab distributor??....those wires for the two cylinders you mention are next to each other, so maybe the wires are switched??...link to MacVP's website....good luck....Mike

http://www.vanpeltsales.com/FH_web/f...48_221-239.htm

[bullrunmotor]

My 40 with a 59 A started missing under a load and got hard to start when hot. I found a bad power valve in the carb.

[ken ct]

Power valves that come in most kits are to high a # like 7.5. Use a #5.5 and .049 or .050 main jets in there if you open it up. Also steel needle + seat and a leather accelerator pump not rubber ones. OMO ken ct.