I got the 311 running, but rough...

I bought this 311 RN a couple months ago and I just rebuilt the carb and got it on today. It has been sitting for about 5 years. I had never heard it run before I bought it, taking a chance on it.

I removed the fuel tank and cleaned it out and removed all of the old fuel.

I checked the compression and had 100, 100, 95, and 70 on #4 cylinder but I could hear a leak coming from my compression tester on the last #4 cylinder, so I am assuming that it is close to 100.

I checked the valve lash and they seemed a little tight, so I set them at .014" as the book called for. All of the valves were going up and down fine with no sign of sticking.

It has new points, condenser, wires and it had brand new Champion D21 sparkplugs in it.

It runs really rough. The only thing I can think of is bad spark plugs. I have never liked Champions, and was wondering what the correct Autolite plugs should be for my 148? I have had bad Champions out of the box before.

What else could I be missing?

The standard autolite plug for your application is a 386, or some like the non-resistor version which is the 3116.

Champion plugs seem to have a substantial number of failures out of the box.

Wonder if they are made in china? Even my lawn mower dosen't like them.

Here now, the Champ plug thing is like kicking someones favorite cow!

It wonders me why the heat range plug installed is way at the high end of the D series plugs. I would remove them and see if they are sooted up. Possibly fuel soaked or worse oil fowled.

I personally prefer Autolite for reasons previously stated on forum and tractors have been my life professionally. I was as pro Champ as the most devoted were but in the 70's Champs plugs started to foul easily and usually just a few hrs after install. Being in the business, we stood behind our work but had to re evaluate the product. We settled on Autolite and never looked back.

It seems to me that a good going over to determine the mechanical condition of the engine before blaming plugs however. Make sure there is a thermostat in the upper hose and working properly, a engine not up to temp can cause plugs problems. Blue smoke indicates oil burning, black, excess fuel. Make sure carb adjustments are right, the air cleaner is clean and airflow unobstructed, I have seen older tractors that the screening in the air cleaner was packed with junk from years of service.

Run it and get a feel for it's condition and let us know, plug preference or no, everyone is here to help.

mEl

Back when Champions were alright I used the D21's as they were harder to foul out, but in the last 15 or so years it's been all Autolite 386 and now 3116's. Do you have the right plug wires? A lot of guys around here put semi-metallic wires on and a 6V system can't fire right with them.

This sounds exactly like the 311 that I worked on last week. The main problem was the advance weights in the distributor were stuck.

Thank you Eagle Doc, that was my next post, many of those distributors are in awful shape below the points plate, excessive shaft bushing and advance tower wear make points adjustment difficult, to speak nothing of the rusty weights and deteriorated advance springs which can keep the dist at max advance.

As controversial as they are to some a Pertronics module unit will compensate for all the wear as the points gap is no longer an issue. They are made in 6-12 V Pos or Neg ground. As some on here have noted, a good starting system is absolutely necessary to use a Pertronics unit, to much cranking voltage drop does not sit well with a Pertronics.

mEl

I agree on the wires. Regular spark plug wire works best on the older tractors. A guy told me a while back it may run on silicone wires (was on a 12v system) but under load it wont handle it. Dont forget the coil, and wiring if you are loosing spark somewhere. I had that on a tractor, the spark was jumping from the side of the coil to one of the terminals.

mEl, a side note on the Pertronix setups is the 6V ain't worth it's weight in mud. The 12V versions are decent. 6V has too much of a voltage drop when cranking to be practical. If you don't have enough voltage when cranking the module will not fire.

I did put brand new metallic 7mm plug wires on with no
change. I will pick up the rest of the stuff tonight after
work. I will keep everyone posted. Thank you for the
helpfulness! Zane

I have worked on a few of the small block gas case engines. What was said about the advance towers in the dist is right on. I have found if you can a delco out of a 611b you are much better off, The petronics will work good on the 12V to solve the problem. Other than that getting the carb righthas been the other issue.

So is the Delco from a 611-B a drop in for the 148 engines?

I installed new plugs, cap, rotor, points, and condenser, even though everything but the cap and rotor were new.

I ended up checking the timing and it was off as well. The distributor and mechanical advance seemed tight.

It started right up and runs smooth now! Thank you for all of your help!

1031D,

What you say dovetales nicely with other posts concerning even 12V systems with bad starter, ratty cables and lo output batteries. I have never worked with a 6V module. I suppose the correct police would object to a Pertronics anyway as they oppose even a neat changeover to 12V. For our purposes, with compression boosts and all the other enhancements, 12V is the easy way to restore reliability in starting.