johnnymag3 2,441 #1 Posted July 17, 2018 12 HP magnum.......312 Hydro pop spit cough pow!!! Backfire repeat runs fine then pop spit cough pow!!!!!! Repeat, restart....... new fuel lines, clean gas, cleans carb, needle and seat fine, fuel pump works fine, will run perfect with half choke...... has new fuel filter new. Tractor has 245 Hrs. on it. Cant quite figure it out? Thought it was the fuel pump, so I popped it off and tested....sucks and pumps fine......took carb apart, spotless in the bowl. Needle and seat work perfect.....this Horse is driving me crazy.. Help......... Thanks John Share this post Link to post Share on other sites
wallfish 15,919 #2 Posted July 17, 2018 (edited) 8 minutes ago, johnnymag3 said: will run perfect with half choke You are matching the air flow to the fuel flow at 1/2 choke. When you open the choke all the way there is too much air to the amount of fuel.. Dirty carb, or you have an air leak some where like the gasket or the throttle shaft. While it's running spray carb cleaner or WD-40 on those areas. If the rpm changes, it is sucking air Check the float and setting too Edited July 17, 2018 by wallfish 4 Share this post Link to post Share on other sites
pfrederi 17,147 #3 Posted July 17, 2018 Magnums are kind of new for me. Is this a Walbro Fixed Jet carb?? If so my sympathy. If not have you pulled the high speed needle and made sure all the holes were clear? Wallfish is right o about air leaks but i doubt with 200 hours it is the throttle shaft. 1 Share this post Link to post Share on other sites
johnnymag3 2,441 #4 Posted July 17, 2018 It is not a fixed jet carb, its a common Walbro, just like my C-160 carb...I did try to spray stuff around the carb, but no no avail...so Im leaning toward something in the carb? The gaskets are fine, and all of my fuel lines are new, I replaced them......old one were nice too, so saved them Share this post Link to post Share on other sites
johnnymag3 2,441 #5 Posted July 17, 2018 Why is the fuel filter half full when I use half choke? and empty when no choke???? CONFUSED Share this post Link to post Share on other sites
johnnymag3 2,441 #6 Posted July 17, 2018 Vacuum is obviously pulling fuel in for me....is my guess..... Share this post Link to post Share on other sites
AMC RULES 36,945 #7 Posted July 17, 2018 http://gardentractorpullingtips.com/carbfuel.htm Share this post Link to post Share on other sites
johnnymag3 2,441 #8 Posted July 17, 2018 Thats 50 pages of mind numbing material, i may die before I get to read all of that..... john Share this post Link to post Share on other sites
pfrederi 17,147 #9 Posted July 17, 2018 pull the high speed needle spraying the carb really doesn't do much... 1 Share this post Link to post Share on other sites
johnnymag3 2,441 #10 Posted July 17, 2018 gonna do just that after dinner, thanks !!! its a start much appreciated !! Share this post Link to post Share on other sites
johnnymag3 2,441 #11 Posted July 17, 2018 ok all done eating, Lasagne roll ups....yum...ready for a Ice cold beer....and now to yank the carb off, and pull the removable components.....screws,,,,,, bowl AGAIN ect. this car has no wear, I promise you something simple is getting to me, and Im overlooking it. after 50 years of dealing with these Kohlers, you would think I would have the answer.....But I dont, and I need to learn something today, or Im not living. will let you guys know what I find Thanks for the responses john Share this post Link to post Share on other sites
johnnymag3 2,441 #12 Posted July 17, 2018 Im hoping for something easy........ Share this post Link to post Share on other sites
wallfish 15,919 #13 Posted July 17, 2018 How about some information on those Lasagne roll ups? Never heard of them. 1 1 2 Share this post Link to post Share on other sites
wallfish 15,919 #14 Posted July 18, 2018 (edited) Just read this on your other thread. " If I run the engine in part choke,it will run fine, but the filter is empty, If I pressurize the fuel tank and fill the Fuel filter, it will run fine until the filter empties.. That kind of proves it's a fuel delivery issue if it runs fine without using any choke when the tank is pressurized, so the carb isn't dirty. If it was, your condition would be constant no matter what. Vent hole in gas cap clogged? Screen in tank clogged? Float not set properly? Just kind a thinking out loud here Edited July 18, 2018 by wallfish 1 Share this post Link to post Share on other sites
johnnymag3 2,441 #15 Posted July 18, 2018 Make Lasagne as per package.....let noodles cool Make the typical filling for stuffed shells, or lasagne....eggs, ricotta.mozzarella,basil,parsley, salt ,pepper, grated cheese, fresh garlic chopperd use homemade sauce from Sundays meal that you cooked all day on Saturday.........................NO RAGU Lay out lasagne noodle, lay some cheese mix on top, 1/4 thick.. roll into a log, careful not to push out cheese filling lay logs in tray, with some sauce on bottom cover with sauce, top with mozzarella, bake 45 min covered for 30 min........., then open for 15 minutes rest for 5 min, then lift out as many as you can eat...!!!! 6 Share this post Link to post Share on other sites
johnnymag3 2,441 #16 Posted July 18, 2018 Im going to strip carb tomorrow....everything else is ok, so Im going in elbow deep in the Walbro must be a critter with a cabin in one of the passages....... Thanks guys, ...have the Mrs. make some roll ups. My passion is COOKING, but my Love is WheelHorse pulling a food cart !!!! Share this post Link to post Share on other sites
johnnymag3 2,441 #17 Posted July 18, 2018 Looked at gas cap, may be the issue?????? will test without cap before I take off carb tomorrow Lots of good ideas before I go elbow deep !!! Share this post Link to post Share on other sites
wildfire305 58 #18 Posted July 18, 2018 Do you have a vacuum gauge? I replaced my fuel pump (see your other thread) and the new pump appeared to function correctly when in hand, but when I had it installed, it would not be engaged by the camshaft. I diagnosed this by putting in a tee fitting on the inlet side of the pump and I saw no needle action. After my conversion (see your other thread) the needle wiggles back and forth with the pump action of the new pump. Share this post Link to post Share on other sites
johnnymag3 2,441 #19 Posted July 18, 2018 I do have a vacuum gauge, and lots of tee type fittings.....will diagnose tomorrow. Thanks Awake thinking @ 11:41 PM instead of sleeping...UGH! 1 Share this post Link to post Share on other sites
johnnymag3 2,441 #20 Posted July 20, 2018 Ive tried everything...........doing the same thing. Im at a loss for ideas Share this post Link to post Share on other sites
wildfire305 58 #21 Posted July 20, 2018 Will it run and die on flammable vapor? Starting fluid, Carb cleaner, wd-40, brake parts cleaner, etc? Share this post Link to post Share on other sites
wallfish 15,919 #22 Posted July 21, 2018 On 7/17/2018 at 8:07 PM, wallfish said: Just read this on your other thread. " If I run the engine in part choke,it will run fine, but the filter is empty, If I pressurize the fuel tank and fill the Fuel filter, it will run fine until the filter empties.. Try using a spare gas tank and gravity feed the fuel to the carb. If it runs right with no problem, the issue is fuel delivery to the carb. and not the carb itself. Share this post Link to post Share on other sites
Bill D 1,599 #23 Posted July 23, 2018 Make sure somthing isn't trying to kill the engine at random. Isolate the kill wire from the magneto and see how it runs. Be careful not to damage the charging system rectifer. If you need help let me know. Bill Share this post Link to post Share on other sites
Copper116 63 #24 Posted July 24, 2018 Might it be possible for an inside the tank screen filter is plugged... letting fuel in a bit at a time... then the lines run dry until it can seep in a bit to repeat the problem. May try back flushing the line that goes into the tank if you know it's got the screen filter in the tank... Just an idea! Good luck. Share this post Link to post Share on other sites
Tuneup 1,416 #25 Posted July 28, 2018 That gravity feed idea is worth a try. I got myself a PVC cap and drilled a hole in the bottom. Threaded a barb and run a hose to the inlet. Worked for years when balancing carbs on old motorcycles. A couple of drilled holes allowed a twine loop to permit it to hang from the garage door runners. Redneck for sure but cheap, fast, easy and durable. You can also watch that Kohler suck that fuel down - man, they are thirsty! Share this post Link to post Share on other sites