Direct Drive Pulling from Buffer Tank

In our setup, we are running a 35 gallon buffer tank to a suction hose that goes straight into pressure washer.

Everything I’ve read has said that direct drive shouldn’t be able to pull water, and needs to be fed, but the pump is directly pulling from the tank and seems to be at full GPM. I’ve triple checked the manual and it is a direct drive pump (it is a predator 4400 PSI 4.2 GPM system from harbor freight).

Is there a reason this might be working well for us? Has anyone else had this experience with the predator series?

I’ve seen countless posts about not being able to pull from buffer tank with only a direct drive because it spins too fast, and I want to make sure everything is up to standard. We are not opposed to switching to a belt driven pump, but will avoid it if it’s unnecessary.

I had a Honda/Cat direct drive setup for a year and attempted to draw from my 35gal leg tank.

While it did draw, it started making disturbing noises and I decided it was time to get a better machine. I think the pump spins too fast causing it to slightly cavitate which is not good for the pistons.

Do you think an inline pump between buffer tank and pressure washer could temporarily solve this problem until a full system upgrade is on the table?

We wouldn’t be opposed to upgrading just the pump within the next 1-2 months, but I am struggling to find a belt driven pump with similar PSI & GPM.

Any advice on a good pump, or what PSI/GPM we need to shoot for on a replacement would be greatly appreciated.

I tried using one of those Harbor Freight electric pumps but kept having issues finding an outlet. It did actually work however.

Man these have gone up, I paid $89 a few years ago.

You’d be better off getting a gearbox and appropriate pump or just selling what you have and slapping down the credit card.

Gotcha. Thanks for all the helpful information -
I really really appreciate it being this new to everything.

The engine is a predator 420cc. So this would essentially be all I need to switch to belt driven?

DD or BD dont determine that.
The pump determines wheather it can pull water or not

It doesn’t? Pretty much everything I’ve seen on the topic says belt driven pulls plenty and direct drive spins too fast so doesn’t pull adequately.

Do you know of a DD pump that could adequately pull 4.2 GPM from our tank?

Cause all if not most BD do. Some models dont., been years since i started out, dont remmember specific models.
Ask the manufacturer

Lol. Stick to food advice man.

Are u sayong that all belt drive pumps are made to suck in water?

Not at all.