A reader's opinions on the Hart-Parr tractor.
I found the article by Wilfred Koskela, page 11, November/December G.E.M. to be very interesting. He had a question regarding the counterweight cast in the flywheel of the old reliable Hart-Parr tractor (bottom of page 14 of that issue). Here is my answer to it:
While it's true that a counterweight here does not seem necessary, the throws of the crankshaft being opposite, on investigation you will no doubt find another at the other end of the crankshaft, (perhaps out of sight, inside of the clutch) (which if I'm not mistaken is inside the belt pulley) These counterweights are opposite (180 degrees from) the crankshaft throws. True, the throws of the crankshaft balance each other, but this is a static balance (balanced only while the crankshaft is not turning). On large bore motors, especially those not of the opposed type, where the cranks are far apart (lengthwise of the crankshaft) considerable vibration would be set up while running. These counterweights overcome a large part of this. A rotating counterweight will not altogether counteract the vibration of a reciprocating piston, but will materially reduce it. By making them of the proper weight the engine can be made to run much more smoothly. On engines of this size the centers of the pistons must be 16 or 18 inches apart, so they would not balance each other very well, being so far apart, while running.
I purchased used, a number of years ago, a John Deere Model B (1936 vintage) and one of the first things I noticed about it was that it vibrated badly. I took the clutch out of the belt pulley and noticed that the pressure plate (which was counterweighted) which was mounted on the splined end of the crankshaft had been put on wrong. The instruction book mentioned a rivet and a short spline on crankshaft which should be lined up when reassembling. The mechanic? either did not notice this or disregarded it and when he tightened up the nut on the end of the crankshaft sheared off the rivet, and had die light side of die pressure plate nearly opposite the crankshaft throw. Reassembling it correctly overcame the vibration.
The flywheel of these has a hollow spot on the back side of rim to offset the weight of the crank throw at other side of the engine.
I hope this answers his question.
I note the information I gave Stan Read was published in the November/December G.E.M. This was word for word as per instruction book. On thinking it over, the part about the needle valve setting, starter pedal and choke linkage may sound a bit ambiguous. Maybe I can tell this better in my own words. On the older models the needle valve is used as a shaft for the choke plate. A quarter turn to the right chokes the motor, so at this time the mixture is made richer not only by choking, but by the needle valve as well, the threads being left hand. Choke plate is fastened to needle valve by a set screw which may be loosened, then needle valve may be adjusted to obtain proper running mixture. Once this is done set screw may be tightened and no further adjustment here necessary. Choke and starting mixture were controlled by automotive type cable running to top of washing machine. On newer models needle valve adjustment was independent of choke. Choke was connected by linkage to starter pedal. When starter pedal was at it's lowest position engine was choked, when pedal was released choking action was stopped. So. if engine needed considerable choking to start, hold down pedal each time it is depressed, if not release it quickly. This is something you would have to get used to. Newer models had right hand thread on needle valve. Both had stop button adjacent to starter pedal. I think they were a very simple, functional, dependable little motor. Mine still has the original Splitdorf spark plug after all these years.
I believe Montgomery Ward's Sattely engines were built by Field-Brundage Co. in nearby Jackson for many years, in later years I think the Hummer Plow Works (address I do not recall) built them, (like that shown on page 32 of September/October G.E.M.) The DeLaval "Alpha" engines I think were built by John Lauson Co. of New Holstein, Wise, who at one time also built farm tractors.
If a hit and miss governed engine seems to have to gulp gas one or more times each time before it fires, also takes considerable cranking to start, the trouble may be a leaky check valve in the fuel line, which allows the fuel to slowly leak back to tank between intake strokes. It doesn't actually get the fuel till vacuum returns it to the level of mixing valve.
The September-October issue has some pictures of an old marine engine. Well, helpful or not, I will say what I heard. A friend of mine used to have a Mullins engine and he said the pictures looked just like his engine.
This is my 16-30 Hart-Parr tractor, with my youngest son, Kevin, standing on the platform. I understand it is a 1926 model. It took me just over a year to restore it, in what got to be not spare time. It has been to the National Threshers Show in Wauseon, Ohio the last few years.
If throttling governed engine seems to need re-adjusting of mixture for varying loads, look to the spring back of air valve in mixer, it may have lost some of it's tension. Stretching it slightly may overcome the difficulty, too much tension here may affect maximum power.
If you do not have ferrules for fuel line connections, a very good substitute may be made by drawing a piece of regular wrapping cord (first wet it with water) across a bar of Fels Naptha or similar laundry soap, then wrap connection with it and tighten down packing nut on it. Gasoline or other petroleum fuel will not dissolve the soap and it will make a leak proof connection. This also makes very good fuel pump packing.
If water jacket is cracked and crack is not over one thirty-second inch in width, it may be patched by what is called rust joint. Put a coat of putty or tallow over the crack, be careful not to get any in the crack. Then fill the jacket high enough to cover the crack with a solution of Sal ammoniac (ammonium chloride). Use one pound to one gallon of water, let stand half an hour or so, drain, and run the engine five minutes to warm it up. When it has cooled down a bit pour solution back in and repeat this several times. If the crack is not too wide it will make a permanent repair.
If you have McCormick-Deering type M engine be sure the crankcase breather valve is in working order. It's just below the crankcase handhole plate. Disassemble it by removing 2 bolts. It should have a spring and leather faced valve in it, it's a sort of a check valve. This serves several purposes, it maintains a slight vacuum in the crankcase making the sight feed piston oiler work better, aids in lubricating connecting rod bearing by suction on grease cup at end of crankshaft which is hollow, and keeps down leakage of surplus oil and grease at various joints disposing of it at outlet where it may be caught in tin can. Makes much cleaner engine. When it's working properly you can hear a faint "put-put" at this location while running. Of course hand hole plate must be in place with good gasket.