3W 85 Twin Cylinder With Unusual Problem.
02-22-2017, 08:10 PM
#1
3W 85 Twin Cylinder With Unusual Problem.
I got a 3W 85 Twin Cylinder With an Unusual Problem.
I am bench running it. I just rebuilt the carburetor. The problem was exactly the same before the carb rebuild.
It will start easily when cold after I choke it, but within about 20 to 30 seconds begins to sputter and one cylinder stops running. The one cylinder will fire intermittently and then stop. It runs for about 10 seconds more with only one side firing and then quit. I cannot get it to start after that.
I have checked the ignition and both plugs fire nicely. The ignition battery is charged. I have tried multiple variations in needle settings but the problem remains the same.
Fuel tank is brand new and flows free without bubbles in the line. Fuel tank is fine.
Any ideas?
I am bench running it. I just rebuilt the carburetor. The problem was exactly the same before the carb rebuild.
It will start easily when cold after I choke it, but within about 20 to 30 seconds begins to sputter and one cylinder stops running. The one cylinder will fire intermittently and then stop. It runs for about 10 seconds more with only one side firing and then quit. I cannot get it to start after that.
I have checked the ignition and both plugs fire nicely. The ignition battery is charged. I have tried multiple variations in needle settings but the problem remains the same.
Fuel tank is brand new and flows free without bubbles in the line. Fuel tank is fine.
Any ideas?
02-23-2017, 06:15 AM
#2
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Just thinking out loud. Does your crankshaft move forward and aft when running? If it does I wonder if maybe the hall sensor is not picking up the signal to command the spark plug to fire. I would also check the mounting bracket to ensure it is tight as well and not moving due to vibrations etc.
if all all else is tight and good another thing to check is the spark plug boots and ensure they are seated correctly. Also make sure the spark plugs are not "as equipped" plugs. If the plugs are good and the gaps are good also if the hall sensor is tight and no other issues are found, I would suspect the ignition module may be breaking down internally. As a last resort you might just send it in to 3W or just decide to give it to me I have a Ziroli that is crying for one. Haha
good luck.
Glenn
if all all else is tight and good another thing to check is the spark plug boots and ensure they are seated correctly. Also make sure the spark plugs are not "as equipped" plugs. If the plugs are good and the gaps are good also if the hall sensor is tight and no other issues are found, I would suspect the ignition module may be breaking down internally. As a last resort you might just send it in to 3W or just decide to give it to me I have a Ziroli that is crying for one. Haha
good luck.
Glenn
02-23-2017, 07:36 AM
#3
I suspect the ignition too. I am going to swap it out with a DA-100 module I have. If that works then we will know. The plugs are CM-6 and look good. I also checked the reeds and they both look good and sealed and still flexible.
Last edited by Cashpoboy; 02-23-2017 at 07:46 AM.
02-23-2017, 08:14 AM
#4
If swaping the ignition does not help , I would look at the carb isolator to check for loosenes ,cracks or leaking seal /gasket . Sounds like it may losing it's ability to pump fuel due to possible air leak .
02-23-2017, 08:17 AM
#5
Have you checked the cylinder to crankcase gaskets? maybe you are loosing base compression after the short runs. How long after the engine quits will it be before it will start again? After it quits, are the spark plugs dry or wet or sooty when you remove them? good luck.
02-23-2017, 08:31 AM
#6
It thought about that too. I am going to change ignition module first, then try another carb, then will look for leaks. One thing at a time and try to isolate this booger. When it first runs, it sounds great like it is good to go and then the sputtering starts. It is an older engine so it could very well be seals. It may be a few days before I can run through the list of possibles. I will keep you all posted as I try each one.
02-23-2017, 09:31 PM
#8
My Feedback: (10)
99% Ignition is bad... been there with 3w before. IF you ignition battery is good, the next thing to do is swap the plug wires. If the dead cylinder moves with the ignition lead you rule out a lot of other stuff. As i recall the old style 3w pickup will drive a da ignition - cant remember but i think the wiring order for the sensor needs changed in the plug..
Last edited by 2walla; 02-23-2017 at 09:40 PM.
04-08-2017, 01:55 PM
#10
OK, tried to swap with DA ignition and could not get a spark. Not sure if I had it wired correctly. Anyhow, I put the old ignition back on the engine and started it. It runs and sounds great for about 5-10 seconds and then one side stops firing and then it quits. After it quits, I cannot get a sputter out of it. Is is flooded maybe?
Frustrating as all get out. I have the carb screws out 1.5 to 2.5 turns each. Is this too much?
Maybe it is flooding. I will try to screw them down to just barely open and see what happens. If the carb is starving, then I can prime the carb and if it continues to fire, I will know it is a mixture issue. Also, one more thing. I am running it upside down with the carb facing up. Is this a concern?
Frustrating as all get out. I have the carb screws out 1.5 to 2.5 turns each. Is this too much?
Maybe it is flooding. I will try to screw them down to just barely open and see what happens. If the carb is starving, then I can prime the carb and if it continues to fire, I will know it is a mixture issue. Also, one more thing. I am running it upside down with the carb facing up. Is this a concern?
