New here w/ Ford 861

[Soundguy]

about the right time period.... gotta have that heat shield.. especially with ethanol gas...

 

[jeff pk]

Found some marks on the flywheel, but nothing like the manual. Looking back through the hole---top to bottom S (in a circle)-4-X-3-1. My guess was the S was TDC, and the X was were I set it at idle. Runs much better with new points and rotor too. Pretty much humming now, starts easier too. Need a heat shield. Thanks again soundguy!

Made this shield today---2 pieces of riveted aluminum, nice and reflective...

 

[Soundguy]

yep.. diffinately needed the heat shield...

 

[jeff pk]

Wasn't a lack of heat shield causing the surging. Just went to mow and after about an hour it started again---idled it down and let it rest, checked the tank and gas---cool, no boil. Seemed to stabilize a bit, so I finished mowing at reduced power. Still rough---but finished and brought it back, and it was moving between 900 and 1500 rpm when I shut it down. I'm going to rebuild the carb and check the linkages first, then get into the governor if it doesn't improve. Anyone know where I can get a rebuild kit for a Zenith 3 99 / 13877 / B6 NN A ?

 

[Soundguy]

did you try to apply some choke to it during the hunting?

ytmag likely has the rebuild kit you seek.

a zenith carb eh? not as user friendly or fuel economical as a MS.. but they generally work ok.

I've rebuilt a few, though prefer a ms. my 850 currently sports a zenith..

 

[jeff pk]

No, didn't apply the choke at the time. Just started it and it seems fine now---no surge and choke just makes it slow down. It only seems to happen after running for an hour or so. What does that tell you?

 

[Soundguy]

i doubt it is carb if it startsfine now.

when it runs rough, that's when you need to apply choke. if that helps it, it is either lean ( vacume or fuel obstruction.. or cracked manifold or bad gasket ).. or it is weak spark.

you can check spark easilly.. orange spark that won't jump 3/16 or 1/4" open air is bad. blue/whit that jumps 3/16 to 1/4 is fine.. think fuel...

 

[jeff pk]

Cracked manifold jumps out at me. When it happens there's a noise around the manifolds that sounds like it could be air blowing in or out. I noticed in another thread you had a propane trick to check for air leaks---would that work with a suspected cracked manifold?

 

[Soundguy]

possibly.. if it's an open to the outside crack...

 

[jeff pk]

Soundguy, went to check the spark, and noticed shocks coming off all the plug wires---not super strong just uncomfortable and a little scary. Is this normal or does it indicate a problem with the electrical system? I changed those plug wires when I rewired it. Finally shut it off and pulled #4 wire, added spare plug and started it. It didn't want to start on three cylinders, but got it to, checked spark, and it seemed weak not jumping 1/4 inch---more like 1/8 and SOME orange, though mostly whiteish...

Pulling choke doesn't seem to help when it stumbles, though it's hard for me to get it stumbling without mowing for an hour. Ran it for a while with the mower turning and the extra load brought on a couple surges...

Just did a spark test at night to see if there was any leaking spark---pulled the wires off the distributor and held them near the cap and the spark was long and vigorous. Noticed some spark on the wire coming into the coil during test. Not the wire between the coil and dist---the other one---the red wire coming from main harness.