Hi all,what a great site you have built,this is my first posting here.My D4 has a broken pony engine.The pony started fine last Saturday and the main engine fired right up as usual.I then turned off the fuel to the pony and cut power at the start switch and then the pony kind of belched,coughed and came to a stop with a noise I can not explain.Now it has no spark at either plug and I only find compression on one cylinder,also makes a very subdued knocking or banging when I spin the pony.The guy I bought it from says the magneto shaft is broke but it seems like the left side piston rod must be broke.Is this a common breakage for these old pony's? Are parts still available for repairs or do most folks switch over to an electric starter at this point? Any observations will be greatly appreciated.
Don Alves:(

Probably as common to break the crankshaft itself. That could take out the valves and mag or one piston, the valves and the mag, but I guess you would have figured that one out already.

Time to pull the sparkplug and put something in it to feel if the piston is going in and out. If it is, then take mag cap off and watch the rotation etc.

Breaking a magneto shaft is pretty common. There are mags and parts for them available. Look at this sticky parts supplier listing. www.acmoc.org/ACMOC_BB/showthread.php?t=492

If there's serious trouble in the engine, your cheapest repair may be an electric starter IF you have the hole for one or don't mind making it yourself. Look at OldMagnet's page on starter conversions.
img400.imageshack.us/gal.php?g=header4oq.jpg

This one for parts sources
www.acmoc.org/ACMOC_BB/showthread.php?t=844

ccjersey,wow,I had no idea there were so many parts suppliers for this old of equipment. Thanks for all the names and addresses,I will definatley be checking with most of them.I have been fortunate to have a friend who is giving me a used pony for parts but I am not familiar with the engine numbers to be sure it will cross over as the numbers are different than mine.My D4 has the number N1 2A3929 on the head.The free pony has the number2H3053 on the head and the number4F8395 on the block.I could not see the block number on my pony.Do you know what numbers would be a match or are the ponys all the same,sorry for all the questions but I have never had to work on anything this big or old before but I think I can do most of it myself if I can find the right parts. Thanks again.
Don Alves

The basic short blocks all interchange with the D2's and D4's but you will have to juggle some of the bolt ons to match your installation.