I was thinking this morning - which is usually dangerous.


On an engine build, to save the bearings from the first time start, we use assembly lube in one form or another. This is basically a grease that will dissolve when oil flows through it, so that first run has full bearing lubrication and doesn't eat itself up even if it takes a while for the oil to flow.

On a jet, the only issue with running dry from what I can see, is the wear ring to impellor clearance (first time start - debris is an issue later). So what if I coated the wear ring with assy lube? I would obviously wash it out before the jet hit the water, BUT it would allow me to fire the new engine / new jet for the first time in my driveway without worrying about it being on the water.

Thoughts ? Other areas I would need to lube?

just take off the drive shaft, and run it as long as you want. the aluminum impeller grows  with rpm or so i was told by jim brock, if you are running tight clearances it will eventually eat it self

Sage advice !

Unfortunately for me, I have to pull the engine to get to the the driveshaft.

Usually there is something that needs to be tweeked on first fire up, I was trying to do that in my driveway then go straight to water. The AL isn't going to grow that much with RPM, however it will grow quite a bit with heat. The pumps would eat themselves up in the water too if it was only about RPM. The water carries away all the heat.

In thinking about that, the assy lube probably would allow me a few minutes of run time, but probably not much more because clearances would still start shrinking with the heat generated, it would just give a little more time before destruction starts.

The intake line does put water to the jet, and seeing where it is, there would be some splash (though not much, it's on the wrong side of the ring) for lube, and the water would carry away heat.

The combo of assy lube and water may be enough to do a few minute test fire with a new pump without damage I'm theorizing. Once the pump has some time on it and the clearances are bigger, that would be more time you can run it assuming you clear the debris out.

 Ive heard you can do it with two hoses , one for the motor and one feeding water to the pump, cabletied to the intake great / loader ( dont let the impeller eat the hose !! ) ?  Any opinions on this idea ? 

The hose on my motor that runs between the motor and pumps has a disconnect in the middle. I hook a hose "t" to it. One goes to the motor, one goes to the pump. I have done this for years without problems. I know other people here have other opinions about doing this.