Help jeepster still runs like $%&&

[justjeepsters]

This 67 Jeepster 225 runs terrible. It has a slight sputter out the tail pipe. It is really hard to start. The choke must be almost shut for it to run and it will die after you drive it for a bit. The air adjustment screws make no difference, the dwell is at 31 degrees and the spark plugs, wires, cap and rotor are all new. It is very difficult to set the timing. I lined up TDC and moved the distributor one tooth. Even though it did appear to be off - this did not help. I just did a compression test and here are the numbers:
#1. 130
#3. 135
#5. 140
#2. 140
#4. 145
#6. 135
Somebody please help me

[graybuck]

Tough to tell from what you are describing. The compression is low in all 6, but balanced. Compresion on mine runs 165-175 accross all cylinders.

From what you describe it sounds fuel related. Try starting and giving it fuel from an outside source. I have a small can with a rubber hose that I put fuel into and dribble into the carb as it is running to test, or you might try starting fluid or propane (ie propane trick).

Timming is very important - did you recently have the chain off, dist out? I don't know a lot of background on where you are comming from.

[RRich]

Sounds to me like you have a big vacuum leak - (by the symptoms and the fact it won't adjust.) Get it running at idle, then spray a good burnable carb cleaner or propane around the carb base, the intake manifold, even the power brake booster and all vacuum lines. Do a search on here for "propane trick."

No leaks found?

If you are still running the original 2G carb - take it off and look at the base gasket at the back.
The thin web in the gasket can leak exhaust back into the intake, causing the symptoms you describe. It's making a constant EGR - Exhaust Gas Recirculation without the valve. Not to worry, almost all of them do it. It acts like a vacuum leak but really isn't.)

Notice the 2 small holes in the intake surface where the carb sits - it's the exhaust crossover. Clean the carbon out of those holes, then find a bolt or something to shove in them, then glue it in solid with JB Weld, making sure to plug the holes completely. Allen bolts work great.

Make sure the base of the carb is flat - use a straight edge. If not, use a piece of glass or tile with an abrasive powder - like Comet or BonAmi powder - scrub the base on the tile till it's flat.

New gasket, put the carb back on, enjoy.

[RRich]

BTW - the compression readings -
To really be of much value other than the fact they are pretty close together, the WAY the readings were taken is extremely important.

-- Engine warmed up, not hot, warm. Cold engines will not give very valid information.
-- Engine ran decently, meaning not too rich, not too lean, and timing about right for the last 100 miles or so.
Too rich - carbon builds up - raising compression readings.
Too lean, or ANY misfire leaves unburned fuel in the chambers, washing the normal oil off the cylinder walls, lowering compression readings.

-- ALL plugs removed - so other cylinders don't influence the test.
-- Throttle blocked wide open - so air can get in with no restriction.
-- An equal number of pulses when readings are taken - so each cylinder is treated the same way.
-- Max of 4 pulses each cylinder.

At least 85% of the final reading should be obtained on the first pulse.
At least 95% of the final reading should happen on the 2nd pulse.
The 3rd and 4th pulses should have very little increase.

Even a fairly low compression cylinder can build up a high enough reading if cranked long enough.

After all cylinders are done, then squirt in about 1/2 teaspoon of motor oil in a cylinder, rotate the engine about 8 times to distribute the oil, then take another reading. Do this for all cylinders but one at a time - oil, rotate, read. Do not oil them all at once.

Engine rebuilders love it when engines get condemned because of the wrong procedure and invalid readings.

[Truckzilla]

I agree with everything said here but also add that they are called odd fire for a reason and the adjustment of the distributor is very fussy.