127 oil film on motor

[Doc Brown]

Well, well, well, I guess I have egg on my face.

The good news:

Timing is set perfectly using the test light procedure I learned reading this forum.

The valve breather issue is solved and baffle plate is correctly installed.

The valves are properly adjusted and the exhaust valve was way out of spec.

The problem of it firing like crazy but not taking off on its own is solved but not by doing any of the above. More on that to follow.




The bad news:

I had ordered a new chinesium carb just to figure out the starting problem. I opened the carb up and neither choke shaft would work due to the way they pressed the plate on the end of the shaft. I pulled the shaft out of my old carb and it actually fit the new carb but not before I had to hunt for the tiny indent ball that fell out when I removed the shaft.

The throttle shaft had to be swapped out as well due to the way the threaded governor shaft coupling was set up. I could have made it work but it was easier to just use my old one if it was going to work. I did have to swap the the actual throttle plate out as my old one was too small for the new venturi.

Mental drum roll as I turned the gas on and allowed the bowl to fill up. Pulled the choke and turned it over and the same old crap! Fire like crazy but won't take off on its own! Frustration level goes to DEFCON 2. I put my test light on the coil ignition wire and turned the key and it lit up as it did before when I checked it.?! ¿©§

I put my meter on it and 12.7 volts. Spark, ignition power, gas, timing set right, valves adjusted, breather issue solved, all check. Out of curiosity or maybe because I'm a commercial, industrial electrical contractor I decided to hook up the test light again to the coil and turn the key it lights up. Turn the key to engage the starter and it stays lit up and the motor fires like crazy but won't stay running, release the key and scratch my head like Stan Laurel.

I then had a suspicion I wanted to confirm. I ran a wire into the bat + and stripped the end of it and turned the key to start and touched the wire to the ignition side of the coil and it fired right off immediately and stayed running! I pulled the wire off the coil and it died instantly.

So what was happening was the ignition switch would hold contact for maybe half a second after releasing the key from the starter engage position and then drop power to the coil instead of maintaining it. I'm a little embarrassed to admit this but if someone else can learn from my stupidity than I'm willing to swallow my pride and share with the forum. The key switch went bad and I have a new one inbound.

The silly thing is it was electrical the whole time and that's what I do for a living but I've learned some new things and tuned the 301 to where it should be. Thank you everyone for all your help and I appreciate it. I am buying a 169 so I look forward to the challenges that come with that.

[ol'George]

When one quits learning, they quit living.
Thanks for sharing, I'm sure it will help others

[West Valley G]

Well that's beauty. Think of all the cool stuff we learned here and now
you have a running tractor. Thanks for taking us along. Glad your running.

Ken

[jcubtroy]

Great story, alot of other tinkerers will benefit from the trips & slips. overthinking is the enemy, stay with basics of fuel & ignition and the world will turn.

[Doc Brown]

Originally Posted by ol'George

When one quits learning, they quit living.
Thanks for sharing, I'm sure it will help others

I hope it'll help someone in the future, thanks for the help.

Originally Posted by West Valley G

Well that's beauty. Think of all the cool stuff we learned here and now
you have a running tractor. Thanks for taking us along. Glad your running.

Ken

Thanks Ken.
There is something uniquely rewarding about solving problems and sticking with it even though it should have been easier to solve.

Originally Posted by jcubtroy

Great story, alot of other tinkerers will benefit from the trips & slips. overthinking is the enemy, stay with basics of fuel & ignition and the world will turn.

Yes sir, thanks for the input.



On an aside I have a question I would like to ask you all. I pulled the spark plug to help find TDC and looked in with a flashlight as I moved the shaft and I couldn't see the top of the piston? Nothing was moving up or down it was just a carbon coated surface. I have never seen that in a small engine before. I thought the piston is just below the plug hole? What am I missing?

[ol'George]

Your not missing anything, some engines have the spark plug hole over a valve,
so you will have to turn the engine over 2x before you see a valve move up /down.

[Doc Brown]

Originally Posted by ol'George

Your not missing anything, some engines have the spark plug hole over a valve,
so you will have to turn the engine over 2x before you see a valve move up /down.

Thanks George.

I was wondering about that so I kept turning the shaft and still didn't see any movement. I must have quit just before the valve popped up.

[ironman]

Does this help?

[Doc Brown]

Originally Posted by ironman

Does this help?

Awesome. Thanks Ironman that would explain it.

[ol'George]

As you can see none of the plug locations are over the piston.