Posted by joe csuti on June 15, 2013 at 03:36:43 from (126.96.36.199):
In Reply to: JD 318 posted by Jonak on June 14, 2013 at 19:06:55:
The most common cause for this mod eng to surge is intake manifold leaking/sucking air at split in same,idle passages in carb plugged/restricted due to dirt or high/low speed needles mis-adjusted.
Check that manifold tight on block & gaskets good,if mounting ok,clean off intake manifold & carefully inspect for loose/broken rivets that hold manifold together & also check for hairline cracks in castings,if no loose/broken rivets or hairline cracks found in manifold,get a spray can of carb cleaner with plastic ext tube.
With eng running at slightly above idle & with ext tube installed in spray can nozzle slowly spray all the way around manifold where halfs joint,if eng speed changes while doing this either one/more rivets loose or gasket bad at joint.If you can pinpoint air leak & it's a small area try sealing same with red rtv sealer,if manifold leaking in several spots,either replace manifold OR drill out rivets & seperate manifold halfs,clean out joint & pack with red rtv sealer,reassemble manifold useing screws,lockwashers & nuts.IF no bad rivets/ air leaks found in manifold consider removing/disassembling carb & cleaning out/blowing out all passages in carb body & possibly rebuilding carb at same time.
Other possible causes of surgeing,problem in fuel delivery system(weak pump,plugged/restricted filter,bad fuel lines between tank/carb,dirt in tank plugging outlet,plugged vent hole in tank cap or cap bad)problem in ign system(coil may be going bad & dropping 1 cyl)internal eng wear or mech problem(worn cyl/rings,sticking valves/worn valve guides,leaking head gasket(s),hairline cracks in block/heads.
Same-Day Shipping! Most of our stocked parts ship the same day you order (M-F). Expedited shipping available, just call! Most prices for parts and manuals are below our competitors. Compare our super low shipping rates! We have the parts you need to repair your tractor. We are a Company you can trust and have generous return policies! Shop Online Today or call our friendly sales staff toll free (800) 853-2651. [ More Info ]
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.