8N builds rpm's very slowly

Thad in AR. · May 11, 2013

I just got an 8N that had set. The motor was locked. I poured atf/acetone in the cylinders and it was free the next morning. I changed points plugs rotor and complete carb kit and started it. It will idle very slow and when you hit the throttle it doesn"t cough or spit but it builds rpm"s very slow. I removed the throttle linkage and ran it by hand and got the same results.It has a slight miss at low rpm and the air/fuel mix screw doesn"t change anything at all open or closed or inbetween. The power jet screw does work. I didn"t change plug wires yet. The longer I let it run the better it got but the next morning it was just like when I first started it. I let it run for 30 minutes at half throttle. I"m thinking stuck/weak valves or timing/timing advance. any other ideas. 1952 with a side mount dist and a MS carb.

rustyfarmall · May 11, 2013

(quoted from post at 12:36:23 05/11/13) I just got an 8N that had set. The motor was locked. I poured atf/acetone in the cylinders and it was free the next morning. I changed points plugs rotor and complete carb kit and started it. It will idle very slow and when you hit the throttle it doesn"t cough or spit but it builds rpm"s very slow. I removed the throttle linkage and ran it by hand and got the same results.It has a slight miss at low rpm and the air/fuel mix screw doesn"t change anything at all open or closed or inbetween. The power jet screw does work. I didn"t change plug wires yet. The longer I let it run the better it got but the next morning it was just like when I first started it. I let it run for 30 minutes at half throttle. I"m thinking stuck/weak valves or timing/timing advance. any other ideas. 1952 with a side mount dist and a MS carb.

Ignition timing might be way off (too slow), but could also be sticking, leaking valves.

billy boy2 · May 11, 2013

Is it hitting on all 4? Pull on plug wire at a time, starting the engine each time. If one is dead, it will sound no different without that plug firing. Way too rich will cause this too,but usually black smokes til it gets some rpms up.

souNdguy · May 11, 2013

make sure she is banigng on all 4 and then pulling a wire down the row makes about the same difference for each.

next. see what a lil choke does when you goose carb.

never hurts to check timing and compression...

Thad in AR. · May 11, 2013

The choke doesn"t help fact is it makes it worse.

8N builds rpm's very slowly

Thad in AR.

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rustyfarmall

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billy boy2

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souNdguy

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Thad in AR.

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