running a jet out of water?

[jeepster21]

I need to do some tuning on my 454, and since there is no open water around I was wondering if I could run the jet pump out of the water. If I did run it i would have a hose spraying on the impeller and ware ring, and the motor woulnt be above idle. Right now I havent run it because it wont start and id like to get it started to. see if i got every thing set up right. it would only be like 10 min or less
Thanks

[speedboats]

depends on the type of pump you have. It really comes down to the rear bearing more than anything else, Hamilton Jet run a cutlass type rubber bearing that requires water lubrication else it'll chew itself instantly, Berkely, AmTurbine, Dominator etc run a cam type bearing that is either in an oil bath or greased, so running with no water in the pump is no problem.

Don't forget to run a hose for the engine coolant...

[Xerophobic]

Be careful running an AT pump dry, the front seal is a mechanical type and also can use some water lubrication. Flashing the motor may be ok but I wouldnt run it for minutes or anything.

Running a Hami dry is asking for wide eye's, dropped jaws and a whole lot of "what the hell is wrong with my/your boat?" lol

[jeepster21]

its a berkley 12jc pump. what about the seals in front of the impeller, do they need to be cooled at all? I heard those get hot and then leak but im not sure..
thanks

[Xerophobic]

Berks use a rope type seal which isnt as sensitive to heat buildup. I'd even fire a hose into the jet intake just to get a bit in there but if you're only talking about flashing on the trailer or running for 15-30 seconds I wouldn't stress too much about it.
For me as long as Im confortable running an engine without water is as long as I'd run the pump without it

cheers

[150aintenuff]

12JC;s are good for about 45 seconds without water the input shaft will melt the coating on the rope seal and require an adjustment after that to keep sealed up especially if flooging a motor to keep it running in tuning stages... i would atleast run a hose on it and keep it at idle if you do choose to run it for longer than a min..

[fasteddie]

Just pull the drive shaft and then the pump won't even come into play. Hook a hose to the motor and run it as long as you need too.

[150aintenuff]

most 12JC berkley installs had only a CVjoint coupler that requires removal of engine to remove... not like alot of hamilton installs that have a short jackshaft, and if he has a hose on the motor it can back flow and feed the pump enough water to lube and cool the shaft...

[jeepster21]

I had a buddy make me a drive shaft with a slip yoke since. i moved the motor ahead a few inches because of clearence problems, now i just unhook the drive shaft and run the motor. I removed the old cv set up so the total distance I moved the motor is like 4 or5 inches forward so it shoudnt affect weight distribution to much.

[fasteddie]

I would be concerned about the wear ring as well, unless someone has installed an oiler to lubricate it.

[Xerophobic]

I would be concerned about the wear ring as well, unless someone has installed an oiler to lubricate it.

An oiler for the wear ring?

The wear ring and impeller do not make contact with each other so Im always baffled by those who are concerned with these parts.

Please explain the oiler system you are referring to?

[fasteddie]

After I gaulded the wear ring to the impeller on our race pump years ago Don Bowers had built an oiler that was installed. We used this in the pump so that we could run it on the trailer. Once this was done we had never had another problem. Oiler was a simple reservoir with fitting into a drilled and tapped hole throught the housing and wear ring. Open the valve below the reservoir and gravity would let slight amount of oil drip in onto the impeller providing some lubrication between the wear ring and the impeller.

[KonaKustoms]

ring should not touch impeller, why oil it?

[speedboats]

where does the oil go afterwards? Just expelled to the environment?

Running and oil bath for the main bearing is real common, but as previously stated the longitudinal clearance to the wear ring should be about .040" for rec boating and perhaps as close as 0.015" - 0.020", but still should not touch. The only way it could thrust forrard is a worn thrust bearing. If you were using the boat for racing then I would suggest that this was the root cause for the gauling...

[fasteddie]

Yeah, I guess it just went right out onto the ground. This thing was only used when the motor was ran out of the water. It dripped such a small amount of oil between the wear ring and the impeller that it was never seen. Yes this was in our race pump. And yes the pump was set up very tight. Maybe I was fed a line of crap?? I am not a pump guy, but I had all the faith in the world for what Mr Don Bowers advised. I bought every gadget he suggested we run. After he did his magic on our pumps they sure seemed to run well. And I believe he had some of the fastest pumps in the country. The problem was eventually solved after the invention of the ratchet release. Just disengage the pump and run the motor as long as you desired.