No experience with this engine, so just tossing out some ideas -
Has the pump been refilled recently? If so, what was used to fill it? Is there a chance the pump motor is struggling trying to pump whatever is in the reservoir because it's too thick?
It sounds like the pump is pulling a lot of power and over heating. If that's true, that big amperage draw is popping a thermal breaker (auto reset circuit breaker) which cools off and allows for another cycle. That breaker could be internal to the pump motor or located somewhere in the engine's electronics.
You might be up for a replacement motor, likely due to it having overheated itself due to that defective switch. If you're real handy, you may be able to remove the tilt motor, and disassemble it for a good cleaning, paying particular attention to the commutator and brush holders. I've been able to save a LOT of motors this way....
Best of luck!