I am having a great deal of trouble keeping spark plugs in my A-4 from getting fouled. I can only use a set from two to four weeks before the engine runs rough or only on two or three cylinders or quits altogether. When I replace the plugs the motor runs fine again !
Thus far I have replaced the points with a set if Ignito's from MMI, replaced the Distributor cap, replaced the plug wires, replaced the coil with IR type that I have always used, and had the carbuerator professionally rebuilt by Vosbury. The gas line has two filters, the latter of which is the polishing filter from MMI.
I have checked the compression on all cylinders and they show 115-120 psi. across the entire four cylinders !!!!. Three separate people , including a pro have reset the timing, and none has had to move it more than a degree.
Oil pressure is 45-50 psi at startup, and starting is very good, and drops to about 30-35 under way when warm. Maximum RPM is no more than 1800 at top speed and the wiring has been checked and rechecked to assure us that the wires are not crossed or missplaced.
This has been a rather verbiose description of the malady but frankly I'm at my wits end ! Anyone have any other suggestions, or thoughts that we or I haven't had as to the cause of the fouling.?
As far as backpressure from the exhaust, a water-lift system was recently installed by Conklin marine but the problem preceded that work. Also I believe that the airgap in the water line to the exhaust should negate any backpressure interference.
Thus far I have replaced the points with a set if Ignito's from MMI, replaced the Distributor cap, replaced the plug wires, replaced the coil with IR type that I have always used, and had the carbuerator professionally rebuilt by Vosbury. The gas line has two filters, the latter of which is the polishing filter from MMI.
I have checked the compression on all cylinders and they show 115-120 psi. across the entire four cylinders !!!!. Three separate people , including a pro have reset the timing, and none has had to move it more than a degree.
Oil pressure is 45-50 psi at startup, and starting is very good, and drops to about 30-35 under way when warm. Maximum RPM is no more than 1800 at top speed and the wiring has been checked and rechecked to assure us that the wires are not crossed or missplaced.
This has been a rather verbiose description of the malady but frankly I'm at my wits end ! Anyone have any other suggestions, or thoughts that we or I haven't had as to the cause of the fouling.?
As far as backpressure from the exhaust, a water-lift system was recently installed by Conklin marine but the problem preceded that work. Also I believe that the airgap in the water line to the exhaust should negate any backpressure interference.
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