85lebaront2 Posted October 28, 2020 Share Posted October 28, 2020 I can't remember ever seeing a heat cross-over that wasn't carboned/plugged up my self. That would not be conducive for the proper function of the automatic choke. If that is the case, an electric choke would be a solution for the lack of heat from the choke stove. Mike's carburetor has one with the control block that would work without a functioning choke stove.https://www.carburetor-parts.com/Electric-Choke-Conversion-Kit_p_4165.html Frank, the worst ones I used to see were the Chrysler LA 318s, they had a heat riser valve that would stick in the open position resulting in almost no heat, which made the well style choke stay on, which made it run rich creating more carbon. You could get a repair kit from the dealer but the valve had to be welded to the shaft (those and the bushings were CRES). I have my shop guys physically check all Chrysler product heat riser valves. The big blocks, 383, 400, 413, 440 if it was working it would rattle at idle until it warmed up all the way. I told more than a few customers who asked about the noise to be glad it was noisy, it meant it was working. I pulled many a 318 intake and burned the carbon out of the crossover and ports in the head, guy in the house behind the shop loved us (not) when we were doing those. At least the 351M and 400 are "dry" deck intakes (no coolant passages) so other than the royal PITA of working on it no radiator draining is needed. Link to comment Share on other sites More sharing options...
grumpin Posted October 28, 2020 Share Posted October 28, 2020 Frank, the worst ones I used to see were the Chrysler LA 318s, they had a heat riser valve that would stick in the open position resulting in almost no heat, which made the well style choke stay on, which made it run rich creating more carbon. You could get a repair kit from the dealer but the valve had to be welded to the shaft (those and the bushings were CRES). I have my shop guys physically check all Chrysler product heat riser valves. The big blocks, 383, 400, 413, 440 if it was working it would rattle at idle until it warmed up all the way. I told more than a few customers who asked about the noise to be glad it was noisy, it meant it was working. I pulled many a 318 intake and burned the carbon out of the crossover and ports in the head, guy in the house behind the shop loved us (not) when we were doing those. At least the 351M and 400 are "dry" deck intakes (no coolant passages) so other than the royal PITA of working on it no radiator draining is needed. Bill, you ever use Mopar Heat Valve Solvent? We used to use that on waste gates on aircraft piston engines. If they were stuck, that and a rivet gun and a block of wood. Let it sit fo awhile then hit it with the rivet gun, free them right up! Link to comment Share on other sites More sharing options...
85lebaront2 Posted October 29, 2020 Share Posted October 29, 2020 Bill, you ever use Mopar Heat Valve Solvent? We used to use that on waste gates on aircraft piston engines. If they were stuck, that and a rivet gun and a block of wood. Let it sit fo awhile then hit it with the rivet gun, free them right up! Yes, but on the 318 it was in the manifold outlet with the shaft parallel to the crank so wasn't easy to get to to bang on. By the time you pulled the right side manifold it was just as easy to replace it as try to free it up and hope it stayed that way. Link to comment Share on other sites More sharing options...
delco1946 Posted October 31, 2020 Author Share Posted October 31, 2020 Yes, but on the 318 it was in the manifold outlet with the shaft parallel to the crank so wasn't easy to get to to bang on. By the time you pulled the right side manifold it was just as easy to replace it as try to free it up and hope it stayed that way. Sry for the slow reply, busy week and heading to Palm Springs tomorrow. Gary- To answer your question I have both a metal tube going from the intake manifold to the choke housing thermostat and it also has a wire going to it as well. I didn’t rotate the choke housing leaner or richer, but it seems like the plate in the air horn is closing too much upon start up. I think I need to watch a couple videos of a correctly working choke to better understand this process. I’m visually oriented and readying about a process doesn’t gel this too well for me. My gut is telling me that it’s coming off the fast idle too quickly, and maybe not getting enough air when cold. It seemed to run better with a couple vacuum leaks induced via removing the air filter while testing this and leaving the hoses normally connected to the filter open. Only after it warmed up more and the plate opened more fully did it started to run better by plugging those temporary air leaks. I’ll have to dive back into this week I return from vacation. Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 1, 2020 Share Posted November 1, 2020 Sry for the slow reply, busy week and heading to Palm Springs tomorrow. Gary- To answer your question I have both a metal tube going from the intake manifold to the choke housing thermostat and it also has a wire going to it as well. I didn’t rotate the choke housing leaner or richer, but it seems like the plate in the air horn is closing too much upon start up. I think I need to watch a couple videos of a correctly working choke to better understand this process. I’m visually oriented and readying about a process doesn’t gel this too well for me. My gut is telling me that it’s coming off the fast idle too quickly, and maybe not getting enough air when cold. It seemed to run better with a couple vacuum leaks induced via removing the air filter while testing this and leaving the hoses normally connected to the filter open. Only after it warmed up more and the plate opened more fully did it started to run better by plugging those temporary air leaks. I’ll have to dive back into this week I return from vacation. If it ran better with the vacuum "leaks" then rotate the housing one notch leaner. That will open the choke plate up just a little bit, adding more air. But, that will cause the fast idle to come off a bit earlier. However, that is a different adjustment, so let's get the choke right first. Link to comment Share on other sites More sharing options...
delco1946 Posted November 1, 2020 Author Share Posted November 1, 2020 If it ran better with the vacuum "leaks" then rotate the housing one notch leaner. That will open the choke plate up just a little bit, adding more air. But, that will cause the fast idle to come off a bit earlier. However, that is a different adjustment, so let's get the choke right first. It’s already rotated quite far forward, prolly around 45-55 degrees forward. Are the other adjustments I can make to recenter/zero the housing such that it is in a more normal position? Ie only 15 degrees leaner / towards the front of truck and while providing more air than what it is currently getting? Or could the spring in the housing be bad/weak? Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted November 1, 2020 Share Posted November 1, 2020 It’s already rotated quite far forward, prolly around 45-55 degrees forward. Are the other adjustments I can make to recenter/zero the housing such that it is in a more normal position? Ie only 15 degrees leaner / towards the front of truck and while providing more air than what it is currently getting? Or could the spring in the housing be bad/weak? Like Gary said *when the truck is stone cold* adjust it so the choke has a gap of 1/8". If you want to remove the cap and see where the loop on the end of the spring is, be sure to get it on the choke tab when replacing. Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 1, 2020 Share Posted November 1, 2020 Like Gary said *when the truck is stone cold* adjust it so the choke has a gap of 1/8". If you want to remove the cap and see where the loop on the end of the spring is, be sure to get it on the choke tab when replacing. Yes, Jim is right. But if you are worried about the spring, pull the cap and look. And as Jim says, make sure the loop captures the arm. Then with the cap against the carb turn the cap towards the arm to make sure the choke closes. That way you know things are working properly. Link to comment Share on other sites More sharing options...
85lebaront2 Posted November 2, 2020 Share Posted November 2, 2020 Yes, Jim is right. But if you are worried about the spring, pull the cap and look. And as Jim says, make sure the loop captures the arm. Then with the cap against the carb turn the cap towards the arm to make sure the choke closes. That way you know things are working properly. If his carburetor has the external pull of diaphragm, either in the air horn or attached to the back of the main body, it needs to be adjusted to properly open the choke initially. Most of these external pull-offs have a two stage operation, first stage is the minimum opening the engine can handle dead cold, then a small spring in the pull-off will exert pressure to open the choke further as it begins to heat up so as not to become over rich. Once this stage is passed, further choke opening is dependent on heat only. The other factor in cold running is the fast idle speed setting, it is always set with engine warm and on a 2150 is identified by an arrow on the fast idle cam. the screw is placed at the arrow and the fast idle is set with the screw. The reason it is set warm, cold is not an absolute, cold engine at 60° is different from cold engine at 80° or 30°. Forward on a Ford choke is leaner, they rotate the inside counterclockwise to close as do Holleys. It should be marked on the cover, but may not be. FWIW, Carter AFBs rotate clockwise to close as the rod runs almost horizontally from the choke housing to the choke shaft and the choke shaft rotates counterclockwise to close where the choke housing inside rotates clockwise to pull the rod forward. Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 2, 2020 Share Posted November 2, 2020 If his carburetor has the external pull of diaphragm, either in the air horn or attached to the back of the main body, it needs to be adjusted to properly open the choke initially. Most of these external pull-offs have a two stage operation, first stage is the minimum opening the engine can handle dead cold, then a small spring in the pull-off will exert pressure to open the choke further as it begins to heat up so as not to become over rich. Once this stage is passed, further choke opening is dependent on heat only. The other factor in cold running is the fast idle speed setting, it is always set with engine warm and on a 2150 is identified by an arrow on the fast idle cam. the screw is placed at the arrow and the fast idle is set with the screw. The reason it is set warm, cold is not an absolute, cold engine at 60° is different from cold engine at 80° or 30°. Forward on a Ford choke is leaner, they rotate the inside counterclockwise to close as do Holleys. It should be marked on the cover, but may not be. FWIW, Carter AFBs rotate clockwise to close as the rod runs almost horizontally from the choke housing to the choke shaft and the choke shaft rotates counterclockwise to close where the choke housing inside rotates clockwise to pull the rod forward. That's the guy you want to listen to, not me. He ran a carb and ignition shop for decades, and has forgotten more about carbs than I'll ever know. Link to comment Share on other sites More sharing options...
Recommended Posts