Case starting problems

On my newly restored case 20-40 tractor---problem is---it runs just fine, after it gets started by belting it up---after it gets warm--I can start it just fine--but not when it is cold,--it has so much compression that it cannott be turned over with the compression releases shut---so compression is not the problem---it has good spark, on time, could it be the plugs when they are under compression, not fireing?????I can't figure this one out. d,j,

These may be some simple checks to do:: switch ON?? Fuel on?? Any other switches that should be on, or off????

I guess what I am trying to do is get to check everything you got fuel??????

Air under good compression is thicker and requires a hotter spark than the air outside the cylinder. Use a plug set at three times the usual gap to check the spark outside of the engine. this may find your problem. JOE

A lot of these early tractors like the Rumely Oilpull start more easily when they are cold than when they are hot. Are you giving it a Good Drink through the priming cups before you crank it...??? Takes quite a bit of Gas to get a combustable mixture in them Big Cylinders when the engine is cold... If you crank it with the cocks open that should help the spark problem some... If that is indeed the problem...

If you don't have HOT spark you will NOT hand start it---been there, done that. One of the reasons it will start when it is belted is because the magneto is ALSO turning over faster.....yeah yeah..I KNOW all about the impulse!!! Widening the plug gap is not only very hard on the mag coil but will cause the plugs to start arcing internally rather than across the gap sooner as the plugs carbon up. You might have good spark but it's not good enough. That's why some of the early 20-40's had a coil box in the cab for BATTERY starting with buzz coils and then SWITCHING to the mag. Craig

I think it is the spark also--can't prove it tho-- I have poured lots of fuel into it--don't know what to do to remedy this one-????? d,j,

I think he's on to something D.J. Why not pretend it's a model T and try starting it with battery and buzz coil to see how it works? Kevin

DJ, If you would like, I would be more than willing to take that machine off your hands. You would not have any more starting problems if I did...let me know what you think

Thanks

Mac Leod

Well--as I think it is spark from the get-go---how does one put a buzz and batt in there-for starting --I guess I am having a senior moment--can't just unhook the mag--explain please!! thanks d,j,

disconnect the mag complete "DO NOT" try to use the mag as your timing, or points in the mag.. that will be the end of the magnets for ever, never to be charged again....

Dan

I am going to start this over so folks will see it-- HOW do I put a batt/buzz unit on my 2 cyl case-to try it---timers--ect---what-what-what--???how is it done on the original tractors that had it that way?? thanks d,j,

You need to make some type of timing device to fire the coils. This picture is how it is done on a 8 hp Cushman twin cylinder. Hope this helps. Wayne Welch




http://www.enginads.com/photos/smokstak/pic75451.jpg

Another veiw of the timer. Wayne Welch




http://www.enginads.com/photos/smokstak/pic75453.jpg

DJ, Just a couple of thoughts. First I am not sure what type of magneto is on the engine. Most magnetos have an air gap built in to keep from shorting out the armature. If you open up the gap in the spark plug to try to check the spark under atmospheric conditions, you may just send the spark to the air gap. Easiest way is to judge the color and strenght of the spark, if you are producing a good "jagged" blue spark around 1/4" long off the plug wire, it probablly isnt the magneto. Next I would look at the length of the reach of your plugs. Are they long enough to reach into the combustion chamber? I have seen this time and time again, the plugs are too short and as the pistion forces all that fuel/air mixture into the base of the plug or the pocket where the plug is located, it simply will not fire. Remember what you are trying to do is start an explosion that progresses from the plug into the rest of the combustion chamber. Finally on setting up a buzz coil, you are right you will need to set up some type of timer, a rotary switch if you will that will be adjustable to get the spark occuring at the right time. Once you get the switch located using a Model T coil is the easy part. The hot lead goes to the contact on the base of the coil, the contact on the top side of the coil is the switch, and the lower contact on the side of the coil is the high tension lead going to the plug. Any one familiar with a Model T wiring should be able to help you out. Getting the timer mounted and set up is the most difficult part. On another thought, for a couple of free drinks, I imagine Neil Davis and I could run up and maybe give our opinions in person. I would really love to see your latest toy. Good luck, hope this helps, Kevin Fielding West Point, Utah

I will do like the price is right---[come on down] glad to have you guys---I wonder if a set of those spark plug extensions would work--they are used sometimes on outfits that have problems --on the other hand they just make the plug longer--don't get the tip any further down in the chamber--very long reach 1/2in sparkplugs might work?? is there such a thing??? d,j,

DJ, Yea, there is such a thing, the Champion is a #31- Gas Engine Special. It has about 1/2-3/4" longer reach than the Champion X. You see originals show up every once in a while on e-bay. I am not sure of anyone making a long reach 1/2" now days. You may need to find originals. I will check my stuff and see if I have a couple. Kevin

When these things were started by battery and switched over to magneto a special magneto with two sets of points was used---Case 12-25 is an example. With some finagling you COULD set it up that way but it would require a switch to COMPLETELY isolate any outside voltage from going through the magneto and you would have to drill a hole in the points cover to accommodate the electric wire from the battery AND you would need TWO coils, of course. Better off getting the mag properly repaired. What kind of mag are you using? KW Model T? As I recall the mag is LEFT hand. KW's are a BEAR to work on! If there is ANY looseness in the points lever roller OR where the points ass'y fits the mag body you are not going to have a reliably hot spark. It'll be all over the map. If you aren't the fussiest man on the planet I'd use a Bosch ZR4. Not hard to come by and are REALLY hot mags and have a tendancy to STAY that way. I DID get the KW on the 20-40 in my shed to be hot and stay hot but it wasn't easy and the owner does hand start it! Craig........... Just for the hell of it, what kind of plugs are you using?

Champion A-25 is long reach, it is for the Maytag singles. Make sure a longer reach plug will not interfere with other internal parts such as moving piston, opening valves, or combustion chamber parts