I have just replaced the pump lines on my convertible and now I am having a problem with the pump motor. It will work for 5 seconds and then just shuts off. After about a minute it will work again. I do not know what is going on here. It seems like the pump isn't turning at the RPMs it should be. I hooked it up to a battery charger to see if it would work better. Still does the same thing. I just don't want to buy a new pump for $300. please help.