Ok first time on a forum, I just required a D6 Cat Dozer from the 50's. where is the serial number? Also I'm working on getting the pony motor running. Not getting spark replaced Spark plugs. next I plan on replacing the point condenser and coil. the magneto is MJK. Finally the drain valves on the heads? they leak abit on the compression stroke when turning over the pony engine is that normal? and what are they for exactly?

 

the drain cocks are to drain excess fuel and oil from the cylinders and also any moisture the idea is you give it a couple of pulls with the cocks open to clear the cyl before closing them, turning on the ignition and setting throttle and choke. for the original valves inline is closed they can be adjusted buy adding a washer under the spring but they need to be lapped in beforehand a little fine valve grinding(lapping) paste works for this you could also use jewellers rouge apply a small amount to the spindle and turn it in the body till both are shined evenly rinse and reassemble with a very light smear of grease adding thin washers or shimstock to set the tension replacements are also available besides at the cost of little valves like that its not worth the effort to relap them.

bonus tip: once you work out what throttle/choke settings work LEAVE THEM SET makes it easier these are notorious for being finicky.

check all the plug leads for cracks and deterioration note they have to be proper wire leads not suppression type with proper metal ends. change the leads one at a time (so you dont get em backwards like I did. wouldnt start till we worked out that was the problem)
check the ignition(kill) switch for correct operation its a (normally closed switch so open is ignition on. (off works by grounding out the mag)
clean the bolting surfaces of the magneto if not clean and good conduction path no spark. the conduction can be improved by cleaning with methylated spirit or shellite LET IT AIR DRY WELL if rough dress lightly with a fine file and clean again the idea is they should be clean and some what shiny and rub a no2B pencil on the bolting surfaces the graphite will help the conductive path. it can make a weak spark a good one. a old mechanic taught me this trick and i have used it with success ever since.

ensure the plug seats are also clean. poor conduction path will give lots of problems.
check the rotor button and cap for cracking and damage clean the rotor button contact strip till shiny al-foil works well for this.
yes a new points and condenser can help too.
check the grounding point on the mag for damage if damaged it will stop it from sparking if current can go to the casing.

A magneto likes real copper core wires. They do not like the carbon core wires.

Clean the points. At this time leave the condenser alone, as all new ones seem to be Chine made and it seems many are bad before you put it in. It yours proves bad then you have to hope and pray you get a good one.

You can replace the petcocks with plugs. The petcock is very handy to see if you are flooding with gas, as well getting moisture out before starting. So maybe check compression on the pony before worrying about what is leaking out.

Thanks Guy's I'll Give these a try next trip to the Dozer as it is 300 miles from my house to our property. I'll give updates on progress once again Thanks

trainzkid88, where can I get new drain cocks? like those

www.mcmaster.com/flow-valves/drainage-va...n/handle-style~flat/

Hi Hayesr700,
Florin tractors has them too, part number 3B9068, just send him an email.

Dana Mayes <This email address is being protected from spambots. You need JavaScript enabled to view it.>

Regards

For ease of starting using a rope, the book said it was good practice to open one up to make pulling the rope a bit easier at times. Just close it off when she takes off. JM