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PopinJohn 11-09-2009 19:56:51 207.119.83.223 456624 Report to Moderator	We have a neighbor whose tractor quits running when hot. Tractor has a 5ft brush hog on it. It has already had all the usual things verified as okay. Carb, distributor, coil, gas cap, fuel line, fuel strainer. Someone suggested that the valve adjustments could be too tight, causing loss of compression when the engine gets hot. Tractor starts right up after 10 minute rest. Any ideas? Y'all already know you can't get the valve cover off without removing sheet metal and gas tank. [Reply]   [Send Email]
Jerry/MT 11-10-2009 16:44:32 206.183.116.129 456701 Report to Moderator	Re: 851 Ford quits when hot in reply to PopinJohn, 11-09-2009 19:56:51   As soon as it quits, jump off and check the spark by pulling the center wire out of the distributor cap, holding it near a good ground and trying a start. You should have a FAT, BLUISH-WHITE SPARK, the color of lightning. If you don"t you need to check the coil and and ignition switch, since they cause a sudden shutdown of the engine and after a cool down period, allow a restart. If the ignition checks out, then check the fuel delivery. My experience is that when the engine shuts down immediately, it"s generally an ignition problem. It it misses, cough and sputters and then stops, it"s genrally fuel supply related. I"ve seen engines overheat due to cooling system problems where they suddenly stop because the piston rings sieze against the cylinder walls but that"s pretty rare.   [Reply]   [No Email]
200cs 11-10-2009 14:54:03 173.64.212.27 456696 Report to Moderator	Re: 851 Ford quits when hot in reply to RICKWI, 11-09-2009 19:56:51   PopinJohn said: (quoted from post at 20:56:51 11/09/09) We have a neighbor whose tractor quits running when hot. Tractor has a 5ft brush hog on it. It has already had all the usual things verified as okay. Carb, distributor, coil, gas cap, fuel line, fuel strainer. Someone suggested that the valve adjustments could be too tight, causing loss of compression when the engine gets hot. Tractor starts right up after 10 minute rest. Any ideas? Y'all already know you can't get the valve cover off without removing sheet metal and gas tank. I would check the ignition coil primary and secondary windings. If it is even slightly out of limits, replace it. I have seen this several times on other engines from cars / 4-wheelers / outboard motors / chainsaws. Runs good cold, coil starts braking down and delivering weak spark when hot.   [Reply]   [No Email]
soundguy 11-10-2009 06:30:46 68.243.13.205 456659 Report to Moderator	Re: 851 Ford quits when hot in reply to PopinJohn, 11-09-2009 19:56:51   I'm with some of the others.. at stall, verify it has spark.. if it has spark, then pull the plug on the carb bowl to check fuel flow. soundguy   [Reply]   [Send Email]
David - Alabama 11-10-2009 05:59:24 68.208.116.58 456655 Report to Moderator	Re: 851 Ford quits when hot in reply to PopinJohn, 11-09-2009 19:56:51   Fuel line to close to exhaust manifold?   [Reply]   [No Email]
Dean 11-10-2009 04:52:14 67.172.13.37 456647 Report to Moderator	Re: 851 Ford quits when hot in reply to PopinJohn, 11-09-2009 19:56:51   John: It's not the valve lash. Though it probably sounds odd unless you are experienced with vintage Ford tractors, it could be the ignition switch. Replacement Ford ignition switches are well known to develop high resistance after extended periods of use, especially in hot weather. This condition is very difficult to diagnose because the symptoms disappear very quickly after the engine stops if, as is likely, the engine stops with the point contacts open. Carry a short piece of wire with insulated alligator clips on each end in the toolbox and short out the switch when the engine stops to verify. Alternatively simply replace the switch with a new one. Dean   [Reply]   [No Email]
Showcrop 11-10-2009 04:31:33 75.67.231.80 456646 Report to Moderator	Re: 851 Ford quits when hot in reply to PopinJohn, 11-09-2009 19:56:51   Timing?   [Reply]   [No Email]
MarkB_MI 11-10-2009 02:54:09 32.178.229.92 456639 Report to Moderator	Re: 851 Ford quits when hot in reply to PopinJohn, 11-09-2009 19:56:51   "Verified as okay" seems a mite vague to me. Make sure the points aren't burned and are gapped properly.   [Reply]   [No Email]
36 coupe 11-10-2009 02:33:20 216.220.250.146 456638 Report to Moderator	Re: 851 Ford quits when hot in reply to PopinJohn, 11-09-2009 19:56:51   Do a compression test when the tractor stalls.   [Reply]   [No Email]
paul 11-09-2009 21:18:47 76.77.197.242 456635 Report to Moderator	Re: 851 Ford quits when hot in reply to PopinJohn, 11-09-2009 19:56:51   Vapor lock. Loose - worn - distributor shaft. Lets the hot vapors get up into the distributor. Condenser. I've had new ones fail under heat. Coil. We put a 1 inch wood block behid ours, moved the coil out away from the hot block a bit, thermal insulated it a bit. Helped a lot. Never had one fail, but they didn't like getting as hot as the location Ford placed them. One or several of those combined will likely cover it. --->Paul   [Reply]   [No Email]
old 11-09-2009 21:16:38 4.245.2.156 456634 Report to Moderator	Re: 851 Ford quits when hot in reply to PopinJohn, 11-09-2009 19:56:51   Bad ignition switch will do just that   [Reply]   [Send Email]
WayneIA 11-09-2009 20:57:32 199.120.65.237 456631 Report to Moderator	Re: 851 Ford quits when hot in reply to PopinJohn, 11-09-2009 19:56:51   It's only a two minute job to take the valve cover off, WITHOUT removing the gas tank and hood. But I don't think you need to go there. If you are SURE of your verified items. than a small gallon of diesel fuel in a full tank of gas will probably solve you "vapor lock' problems. Better double check the ignition switch and/or the coil again.   [Reply]   [Send Email]
Stephen Atkins 11-09-2009 20:49:53 71.222.146.251 456628 Report to Moderator	Re: 851 Ford quits when hot in reply to PopinJohn, 11-09-2009 19:56:51   We had an 850 Ford that would not run when it got hot.(didnt like to be worked hard) Turned out to be vapor lock. The gas line was routed too close to the exhaust manifold. Good tractor. steveormary   [Reply]   [Send Email]