(800) 853-2651
SHOP NOW

JD R pony motor

S

sluggo4431

New User
Hello
I just got a 1949 R JD, has not been running for about 7 years (was drove in barn and shut off) The pony motor will not start, checked and getting gas, spark, tried adjusting gas and air seemed like it wanted to idle (barely) and would not get up to speed. also seems like left cyl wants to flood easy? air cleaner cleaned also. I"m not positive the plug wire are right? and what compression the pony motor should have?
Thanks Doug
 
Not as familar with the R pony (2 cylinder) as the later pony (4 cyclinder), but sitting up typically causes rings to stick, carb to get gummed up, etc. Did you drain the fuel system completely and put new gas in it?
If you have not had it apart, who knows what may have made it's way inside.
 
I'm not 100% sure, but most opposed twins I've seen fire both spark plugs at the same time, shouldn't matter which wire is where. I would do a compression test, check valve operation too.
 
Put new plugs in first and clean the pickup screen in the fuel tank and clean the tank also. take the fuel line off the carb and blow back threw it to the tank also take the fuel valve out of the carb and clean valve and the fuel fitting.I have 2 Rs and the ponys can be a real pain but they are a simple gas eng . Ck the oil for fuel contamination if it is flooding a cylinder or it WILL destroy the pony motor real fast.
 
the fuel line has a check ball in it, & this needs to be free. Whenever i've run my pony out of gas its been a real pain to start. the "carb" is just a simple mixing valve but still needs to be clean & free. The points in the mag have likely oxidized enough that the spark is weak. Check your plugs & go a step hotter, it helps a ton. the pony never gets hot enough to keep cold plugs clean unless its in like-new condition. once you got good strong spark usually just choke till it fires & it should take off. yours should have the adjustable throttle on it, mine likes to start at about half throttle. if its worn it wont have much compression but they'll still run ok like that. clean the corrosion off the inside of the cap on the mag too. Can you hear the mag impulse tripping? it should be easy to hear. if its not it wont start. you may have a broken spring. good luck.
 
Thanks for all the advice. fuel line ch valve is working, I cleaned points, cap and the mag impluse is tripping. I did replace the plugs but with what the service manual calls for.
Thanks doug
 
mine had champion d14's in it & I went up to the d21's in mine, works great. there are 16's & i think 18's or 19's too. i would try autolite or ac, just make sure they're non resistor. maybe a mouse chewed a plug wire? you could also have a bad condenser in the mag? verify strong spark. check intake/air cleaner for mouse nest or some other restriction. exhaust also. I have to crank mine forever & a day if it runs out of gas or floods. if plugs are dry try a shot of carb cleaner or gas in the cylinders. if i run it out of gas it always floods & wets the plugs when i try to start it the 1st couple times. I dry them with a small propane torch then it goes.
 
Thanks
I will try to get hotter plugs this evening? also I am not sure which plug wire goes to # 1 some one may have changed them around? There is a fair oil leak from the pony motor on the left side (flywheel) don"t see where it is coming from?
Thanks again for the help this forum is great
Doug
 
I would just keep it full each time before using it & see how it goes. The pony has no bottom to the engine - it seals to the main engine. The gasket could be bad there or the rear main seal on its crankshaft. Also the front transmission seal-i believe it takes engine oil also,I'd have to look in my manual.do not use high octane gas,get 87,or in high altitude 85. the higher octane is harder to light without high compression & floods easier on low compression engines.
 
You must log in or register to reply here.

Similar threads

J
A 720 pony saga
Replies
10
Views
640
buickanddeere
B
R
More JD 70 Pony Motor Frustration
Replies
14
Views
999
Blksmok
B
F
John Deere Model R Video Series
Replies
1
Views
409
UncleCarl
U
F
Model R Decompression Adjustment
Replies
2
Views
434
fixer2u
F
R
JD 70D Pony Motor Spark
2
Replies
21
Views
1K
Blksmok
B
Tractor Parts Tractor Manuals

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Copyright © 1997-2024 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters
Website Accessibility Policy

Back
Top