my 42 jd A hand start

my tractor is hand start and its really hard to get started.. people have told me to make sure that its at tdc how do you know when its at tdc? and people have told me something about 7/8 whats that?

Look at your flywheel, there is a mark that indicates top dead center. That is when the piston is clear to the top of the stroke when the spark plug fires. Once it fires, it explodes the gas and sends the piston downward. Think about it, if the explosion was to happen to soon, it would force the piston downward before making the complete revelution--thus it would kick backwards.

Now top dead center on a JD two cylinder the motor lays flat, unlike 99% of the engines, so the positions-downward etc is actualy not the exact words to use. It is however the terms that is always used.

I would like to suggest a owners manual in a very polite way to you before someone gets all over your case in a disrespectfull maner about it. It happens often here, by a few idiots that probably are just as rude in person. So beware, and just brush it off when it happens---99% of these folks will go out of their way to help you.

I should mention that top dead center is the one that you can feel pressure fighting you to compress the gas and air mixture as ypou get near the top dead center position. By the way that is the cylinder that is closest to you when you crank it over--called no one piston.

On your flywheel there's a LH impulse mark. When that reaches the position marked at 3 o'clock the mag should snap and fire. This should be when the left hand piston is at the compression stroke and TDC. 7/8 is the size of spark plug for most of the pre 40's John Deeres. Ron Mn

Are you opening the petcock for decompression? Don't know if there is one or two. Dave

I answered some of this for you before somewhere on the boards.......,,,,,,,When the left No 1 piston is at TDC the Left Hand Impulse timing mark on the Flywheel is in the 3 o clock position in line with a flat mark on the tractors side........Thats when the mag needs to snap/impulse to fire the left No 1 plug.......the start/impulse timing can be set by the lag angle on rear of mag and/or loosening it and rotating forward CW to retard or backwards CCW to advance.......

Older plugs were 7/8 while later were 18 mm, I already offered my advice for which to use

You need a manual, were glad to help but it would take us 100 pages to type all you need to know, sorry

best wishes now and good luck

John T