Carburetor Guys

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   Gentlemen,I have a TSX -853 carb that is giving me fits. I have it on a CA, for pulling, with a 160 cid motor wit about 12:1 comp. It is timed with a vacuum gauge to 22 in. of vac, points are set at .020, float is at 1/4 inch rise. The problem is that it will not idle below 800-900 rpms. Trying to go any lower results in the engine dieing with a hard restart.  It pulls strong on the higher end, but will not idle well. When decellerating from the high end, to idle, it will also die. The carb has been soaked overnight in solvent and is clean enough to eat from. Is there still blockage internally or do I need to drill out one of the jets or other mods? Is this carb enough or too much for this engine? I use the same on a WD 240 engine with good results. What possibly could be the problem? 
tks for your help with this.
dgerth

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dgerth Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 27 Nov 2012 Location: NC Wash Points: 172	Post Options Post Reply Quote dgerth Report Post Thanks(0) Quote Reply Topic: Carburetor Guys Posted: 22 Mar 2015 at 5:51am
	Gentlemen, I have a TSX -853 carb that is giving me fits. I have it on a CA, for pulling, with a 160 cid motor wit about 12:1 comp. It is timed with a vacuum gauge to 22 in. of vac, points are set at .020, float is at 1/4 inch rise. The problem is that it will not idle below 800-900 rpms. Trying to go any lower results in the engine dieing with a hard restart. It pulls strong on the higher end, but will not idle well. When decellerating from the high end, to idle, it will also die. The carb has been soaked overnight in solvent and is clean enough to eat from. Is there still blockage internally or do I need to drill out one of the jets or other mods? Is this carb enough or too much for this engine? I use the same on a WD 240 engine with good results. What possibly could be the problem? tks for your help with this. dgerth

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PaulB Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 12 Sep 2009 Location: Rocky Ridge Md Points: 4753	Post Options Post Reply Quote PaulB Report Post Thanks(0) Quote Reply Posted: 22 Mar 2015 at 6:09am
	I sounds as if the idle circuit is not functioning properly. With the carburetor adjusted as you want it, take it off and see if the idle slot (or hole) is exposed. If not it will have to have the slot cut further, or if you have an idle hole, drill a small hole in the butterfly so the idle screw can be backed out some. With that much compression, the fuel curve will definitely need to be altered. Do you have an exhaust temperature gauge on it to see if your're getting the fuel you need? How may degrees is you static timing? What is it at full speed?

DrAllis Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Points: 20528	Post Options Post Reply Quote DrAllis Report Post Thanks(0) Quote Reply Posted: 22 Mar 2015 at 8:35am
	I would try it on a different (240) engine and see how it acts and proceed with repairs and changes from there.

Hudsonator Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 21 Oct 2009 Location: Tennessee Points: 2113	Post Options Post Reply Quote Hudsonator Report Post Thanks(0) Quote Reply Posted: 22 Mar 2015 at 12:11pm
	For whatever reason, most slow speed circuits in tractor carbs do not work right anymore. I have had to correct every single one in the home fleet. They run way too lean and have caused overheating and head gasket failure. The "gasoline" fuels these days must be more viscous, or harder to pull through the emulsion systems, than when these carbs were originally designed. Of course, no cure helps a dirty carb/circuit - so make sure its all clean. I've had to open up the air bleed jet on the idle/low speed circuit at least .003" on about any carb I've touched for whatever purpose. While the common knowledge is larger air bleed = leaner mixture, it appears as if the air bleeds are so small that not enough vacuum signal is being transferred to the low speed circuit for it to work as it should. Hence, .003" larger and then the normal rationale regarding bleed tuning seems to start applying. On a marvel, its the tiny brass jet in the top half of the carb. Most of them are .030 to .032" stock and I'll open them up .003" to start with and go from there. The smallest air bleed jet I've encountered on an Allis was a Zenith replacement carb on a D14 @ .028", same .003" increase straightened it right up. You know you've got it right when your tractor is idling with no skipping and the idle mixture screw is between 3/4 and 1 full turn out with max vacuum. If you have a buddy in the heating/cooling industry with some gauge drills for propane/natural gas orifice tuning - they are the best to use to step up your jets a tiny bit at a time. Edited by Hudsonator - 22 Mar 2015 at 12:23pm
	There isn't much a WC can't do. WD's just do it better.

dgerth Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 27 Nov 2012 Location: NC Wash Points: 172	Post Options Post Reply Quote dgerth Report Post Thanks(0) Quote Reply Posted: 25 Mar 2015 at 5:54am


dgerth Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 27 Nov 2012 Location: NC Wash Points: 172	Post Options Post Reply Quote dgerth Report Post Thanks(0) Quote Reply Posted: 25 Mar 2015 at 6:02am
	Gentlemen, Don' t know what happened to the first one, I'll try again. I took the Doc's suggestion first and swapped the carbs from the CA and WD and so far, that seems to have cured the problem. They both run and idle as they should. Haven't pulled them yet but have a practice pull coming up to test. Thanks guys for the input. dg