Crawford151
New User
I have a 1964 MF35 with what I believe to be a Continental Z134 (4 cylinder), engine. The problem I'm having is after running the tractor for awhile (30 minutes to 1 hour), the engine begins to backfire through the exhaust and loses power. The backfires at first are barely noticeable "pops" coming from the exhaust. However, after that starts, when I shut the tractor off I get a burst of flame coming from the exhaust. Also, when I was bush hogging (a pasture with 12"-18" tall grass), before the engine started "popping", the engine would get bogged down (a 500-600 RPM drop), several times during each pass. But after the "popping" started, the engine would bog down with a 700-1000 RPM drop, and never climb back up to the RPM I had started with. However, previous seasons, the tractor would do the same field without any decrease in power, regardless of how high the grass was.
Over the winter I performed the following to the tractor:
1. Complete fluid exchange (oil, hydraulic fluid, coolant);
2. Replaced the hydraulic pump;
3. Rebuilt the carburetor, (not sure if my settings are now correct);
4. Replaced a missing spring on the governor and adjusted it;
5. Replaced the friction pad on the throttle;
6. Installed a "tee" in the fuel line with a return back to the tank, (someone had told me the engine was vapor locking, and this would cure it);
7. Replaced the clutch, pressure plate and throw-out bearing;
8. Installed a high-temp coil;
9. Full tuneup (plugs, condenser, wires, points, rotor & cap);
10. Replaced the speedometer cable;
11. Replaced the oil pressure line; and
12. Adjusted the valves.
Anyway, I would really appreciate any help with this problem. The only thing I can think of is the carburetor setting is too rich and fuel is building up in the exhaust manifold. But I need a second opinion, even it's to only tell me how to properly adjust the carburetor.
Thanks for taking the time to read this post and I look forward to your input.
Over the winter I performed the following to the tractor:
1. Complete fluid exchange (oil, hydraulic fluid, coolant);
2. Replaced the hydraulic pump;
3. Rebuilt the carburetor, (not sure if my settings are now correct);
4. Replaced a missing spring on the governor and adjusted it;
5. Replaced the friction pad on the throttle;
6. Installed a "tee" in the fuel line with a return back to the tank, (someone had told me the engine was vapor locking, and this would cure it);
7. Replaced the clutch, pressure plate and throw-out bearing;
8. Installed a high-temp coil;
9. Full tuneup (plugs, condenser, wires, points, rotor & cap);
10. Replaced the speedometer cable;
11. Replaced the oil pressure line; and
12. Adjusted the valves.
Anyway, I would really appreciate any help with this problem. The only thing I can think of is the carburetor setting is too rich and fuel is building up in the exhaust manifold. But I need a second opinion, even it's to only tell me how to properly adjust the carburetor.
Thanks for taking the time to read this post and I look forward to your input.