hardknocks Posted July 3 Posted July 3 HI ALL got trouble with a real good miss on my 666. when i bought the tractor about 2 years ago. I put in pertronix electronic ignition, there Coil they recommended and new plug wires they recommended. new cap and rotor, Had a bad intake gasket so replaced it and sent carb off and had it rebuilt. after i got it all back together it ran descent but not perfect. ,didnt backfire Just didn't run correctly. but i used it and ran well enough wasn't a concern. now this year it will hardly run. I have checked timing and its at 18degrees. put new plugs in. even put new electronic ignition on it again. still runs terrible. cant drive it. I took a compression test. removed all spark plugs. checked every cylinder #1 145, #2 136, #3 140, #4 148, #5 150, #6 145. and they all hold compression on gauge. i wouldn't think a bad valve. so i remove all plug wires and just lay them on plugs. start engine and pull each wire from plug and they all have great spark to each plug, but #6 does not affect the engine when removing wire and also #2 makes a little difference but very little.. i have even put a new OEM zenith Carb on it. so now I'm stumped on why it is misfiring. i feel like compression is good enough to run. hopefully somebody has a idea for me to try.. it does black smoke some and im figuring its from #6 cylinder thanks Quote
HydroTek Posted July 3 Posted July 3 153624 on that firing order -- you have it correct ? 18 degrees at high idle ? The check valve in the compression tester holds the air in the gauge -- when you quit cranking the cylinder pressure falls to zero -- also need the throttle open when testing for compression -- then crank 3 or 4 compressions while watching the gauge , so you make good comparisons Still -- you have no fire on the plug for 2 and 6 or intake gasket is leaking and they are not getting fuel Spray wd40 around the intake at 2 and 6 to see if that makes the cylinder fire with the engine at slow idle -- also can use a pump oil can and 30 weight oil -- will make a temp seal on the gasket 1 Quote
Jeff-C-IL Posted July 3 Posted July 3 Take some pictures of the plugs and post them. The plugs often give you clue. White, black, oily...... Quote
Sparky Posted July 3 Posted July 3 I'll also add, when doing a compression check, remove all plugs at the same time, not one at a time. That will trip you up if you have a blown head gasket. Throttle wide open, battery whipping the starter over, crank until the pressure quits building in the compression gauge. Travis Quote
hardknocks Posted July 3 Author Posted July 3 2 hours ago, HydroTek said: 153624 on that firing order -- you have it correct ? 18 degrees at high idle ? The check valve in the compression tester holds the air in the gauge -- when you quit cranking the cylinder pressure falls to zero -- also need the throttle open when testing for compression -- then crank 3 or 4 compressions while watching the gauge , so you make good comparisons Still -- you have no fire on the plug for 2 and 6 or intake gasket is leaking and they are not getting fuel Spray wd40 around the intake at 2 and 6 to see if that makes the cylinder fire with the engine at slow idle -- also can use a pump oil can and 30 weight oil -- will make a temp seal on the gasket i should have mentioned i sprayed all around the intake manifold for leaks and there was no change yes high idle for 18 degrees. yes firing order is correct. compression never falls when i stop cranking it over. but i did not have throttle open just at idle postion i can do another compression test and post pictures of plugs. i can put each plug on wire and ground it out and they all fire Quote
HydroTek Posted July 4 Posted July 4 3 hours ago, hardknocks said: compression never falls when i stop cranking it over. You can remove the gauge from the engine and the pressure will stay in the gauge check valve in the gauge holds that pressure 2 Quote
hardknocks Posted July 4 Author Posted July 4 did another compression test #1-142 w oil-165 #2-135 w oil-155 #3-138 W OIL-156 #4-145 W OIL-177 #5-150 W OIL-180 #6-143 W OIL-168 Quote
hardknocks Posted July 4 Author Posted July 4 here is picture of spark plugs these where new plugs but have started and ran it numerous times trying to figure out the problem. they are black for sure.. new carb was installed today but never made a difference on run quality Quote
Sparky Posted July 4 Posted July 4 In my opinion, plugs almost always look like that. Take it out, hook it to a plow and bury that plow....then you'll get a good reading on plugs. Travis Quote
Gearclash Posted July 4 Posted July 4 Those plugs are a mess. Looks like gasoline fouling plus a little oil burning. Try a hotter plug. Carb might be too rich too. 1 Quote
Straanger Posted July 4 Posted July 4 Mark the plugs and change which hole they’re in, then do your pulling the plug wire test to see if the miss stays in the same hole or follows the plug. 1 Quote
ny hay farmer Posted July 4 Posted July 4 how about a birds nest on intake side of air filter, happened on a 1086 to me is the advance working in the distributor, dont forget to goto parts store and get some lead substitute and put in gas 1 Quote
supermechanic Posted July 4 Posted July 4 Engines need to breathe. Is the muffler clear? Once had a car that had a cat converter melt, had no power and fouled plugs. Quote
Gearclash Posted July 4 Posted July 4 1 hour ago, Chester5732 said: I’d put the points back in. I wouldn't. Pertronix isn't perfect but I've found it to be better than points/condenser. 2 Quote
hardknocks Posted July 4 Author Posted July 4 Ive changed positions with plugs and its always #6 defiantly. I cant take it out and pull it hard. once you get going it will barley run. and backfire some but sounds like running on 4 cylinders when i bought the tractor last year i put a brand new muffler on and a new upright pipe from manifold. and have taken the air cleaner out and cleaned everything. even tried running it with intake tube off carb to see if it made a difference. but nothing. I'm thinking i need pull head. ive pretty much tried everything but putting points back in. i hate to do that because i have tried 2 electronic ignitions and runs the same exact way. i run non ethanol gas. never added lead substitute, and i use viscosity 30w low ash Quote
Gearclash Posted July 4 Posted July 4 If your plugs are gas fouled they need to be tossed. Once they start to misfire because of the carbon coating on the insulator nose they can never be made to work properly again. Oil fouling is a different matter. How did the engine run right after the plugs were replaced? Quote
hardknocks Posted July 4 Author Posted July 4 i have put a new zenith OEM carb on yesterday morning with old plugs. i can buy a new set and try that. what plugs would be best, should i go with a hotter plug?? if so does someone have a P/N Quote
Chester5732 Posted July 4 Posted July 4 7 minutes ago, hardknocks said: i have put a new zenith OEM carb on yesterday morning with old plugs. i can buy a new set and try that. what plugs would be best, should i go with a hotter plug?? if so does someone have a P/N AC c87 plugs. Quote
HydroTek Posted July 4 Posted July 4 D15Y champion is what goes in there Looks like carbon fouling on those plugs -- loose flaky carbon that would mean running way too rich Can you post a vid of this engine idling ? -- have to post to youtube -- then post the link here Quote
supermechanic Posted July 4 Posted July 4 Weak spark will cause misfire and fouling. Snappy blue spark is what we are looking for. You should be able to pull the coil lead out of the tower while running and get about 3/4 inch-long spark to the wire. Orangish, wispy spark that blows out at maybe 3/8 of an inch is just enough to get the engine running, put a load on it and it falls flat on its face. 1 Quote
hardknocks Posted July 4 Author Posted July 4 yes i will take a video shortly. and upload. so use D15Y plugs or AC c87 Quote
hardknocks Posted July 4 Author Posted July 4 43 minutes ago, HydroTek said: D15Y champion is what goes in there Looks like carbon fouling on those plugs -- loose flaky carbon that would mean running way too rich Can you post a vid of this engine idling ? -- have to post to youtube -- then post the link here i cant get but 4 champion plugs today but they have NGK 2910. whats your thoughts Quote
supermechanic Posted July 4 Posted July 4 Autolite 386 work also. If the parts man only has ngk's, run them. Difference between brands is not as important as the difference between carbon fouled and new. Quote
Chester5732 Posted July 4 Posted July 4 11 minutes ago, hardknocks said: i cant get but 4 champion plugs today but they have NGK 2910. whats your thoughts In my experience, anything other than Champion. I could never get more than a day from them. I switched to AC and get years of service. Quote
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