I have an 85 hp 3 cylinder Force OB, 1986, Model 856x6m, S/N 3614.
The bottom cylinder will not fire at both idle or higher RPM. Upper cylinders run fine. I have tried the following with no success.
-changed / swapped plugs
- swapped carbs
- swapped coils
- Compression top to bottom 130, 125, 100 psi warm, with oil add psi 10 to all. Spec= 165 psi
-Lots of spark present
-Reed valves are good
-Replaced crank seals
-Replaced rings, old rings were binding and crusty at pins (all 3 pistons)
- new head gasket, old looked fine
-Inside the engine showed very little wear. Cross hatch intact in cylinders, no scratches. Carbon coated piston tops,
Compression with new rings 100, 100, 100
The only thing left I can think of is the CDI black box, but the is strong spark. could the timing be off? Timing is generated from the stator, which can't change, right? The stator looked good, no burn marks
Any ideas? or suggestions?
The bottom cylinder will not fire at both idle or higher RPM. Upper cylinders run fine. I have tried the following with no success.
-changed / swapped plugs
- swapped carbs
- swapped coils
- Compression top to bottom 130, 125, 100 psi warm, with oil add psi 10 to all. Spec= 165 psi
-Lots of spark present
-Reed valves are good
-Replaced crank seals
-Replaced rings, old rings were binding and crusty at pins (all 3 pistons)
- new head gasket, old looked fine
-Inside the engine showed very little wear. Cross hatch intact in cylinders, no scratches. Carbon coated piston tops,
Compression with new rings 100, 100, 100
The only thing left I can think of is the CDI black box, but the is strong spark. could the timing be off? Timing is generated from the stator, which can't change, right? The stator looked good, no burn marks
Any ideas? or suggestions?