Need help! All systems perfect for 14 years. Changed filter sand for first time before opening pool. (My pool is located in an area that has very little debris entering the pool.) The old sand was very clean but thought it was time anyway. Sealed the center tube, added the new sand and all went well. (The new sand may have nothing to do with my current problems but thought I would mention.) Priming the pump for the first time was difficult...took much longer than normal. I noticed a dark bunch of gunk fly through the strainer basket and then priming started as normal. Everything was now working as it should, but slowly I began to have problems with the motor getting hot and then tripping the 20A circuit breaker. This continued on and off for a week or so. I decided it may be the gunk I saw in the strainer basket...maybe fouled the pump? I rebuilt the pump with all new parts and seals even though there was no sign of damage or excessive wear. Same problem with blown circuit breaker continued. No change in head pressure...always at 15-16 lbs. (It's a new pressure gauge.) No work had ever been done on the pump or the motor. Last resort, I replaced the motor. The new motor, just like the old motor sounds like a sewing machine and is running smoothly and quietly, but the circuit breaker continues to trip. Both the old motor and the new motor are drawing about 9.5 amps...tested with my clamp around meter. The motor says it should draw 7.6 amps on 220V. Any suggestions would be appreciated. Thanks in advance.