As you see, it often helps to ask the question in such a manor as would get you the answer you're looking for.
"How do I run a Jacuzzi 12yj jet equipped marine engine in my boat (river fishing boat, not PWC) in my driveway (on a trailer) without damaging either motor or jet?" That should eliminate most of the "trolls".
Now to the problem, not that I have the real solution, but I have some experience on jet boats, but I have destroyed a lot of good stuff in the last half century, so I do know of what I speak.

Lets start with some clarification:
Is it a Jacuzzi 12yj jet (neat) or a Jacuzzi 12yj jet Golden Eagle?
Does the marine engine get its coolant from the jet auxiliary water outlet?

What would I do? I'd remove the Impeller X Cut No. 4906 (1 of 10 different cuts)
and re assemble. Then T into the coolant line. Then, I'd probably discover that when I turned on the water, most of it went out the jet intake, so I'd block that and discover that most of it was going out the thrust nozzle so I'd block that (allowing some to flow so that everything is cool in the jet housing.

That could work, but remember "I have destroyed a lot of good stuff in the last half century" but I have also fixed a lot of broken stuff that "they" said couldn't be done (usually because I broke it first).

The first thing I would do is get the service manual or at least go to the local Jacuzzi authorized repair facility and ask what they do to get around this problem. Asking us, would show questionable reasoning abilities on your part. I mean really, would you trust the knowledge and advice of a news group when four out of five responses don't address the problem or just keep saying you cant do it?
Go slow and Good luck
Shawn

"R Mac" wrote in message news:TRJve.102800$El.64220@pd7tw1no...
| Does anybody know if its ok to run a Jacuzzi 12yj jet in the driveway to
| tune up the engine? Is there any seals that need to worry about running dry?
| If so is there a way to run water to the critical parts?
|
|

Mungo Bulge wrote:
As you see, it often helps to ask the question in such a manor as would get you the answer you're looking for.
"How do I run a Jacuzzi 12yj jet equipped marine engine in my boat (river fishing boat, not PWC) in my driveway (on a trailer) without damaging either motor or jet?" That should eliminate most of the "trolls".
Now to the problem, not that I have the real solution, but I have some experience on jet boats, but I have destroyed a lot of good stuff in the last half century, so I do know of what I speak.

Lets start with some clarification:
Is it a Jacuzzi 12yj jet (neat) or a Jacuzzi 12yj jet Golden Eagle?
Does the marine engine get its coolant from the jet auxiliary water outlet?

What would I do? I'd remove the Impeller X Cut No. 4906 (1 of 10 different cuts)
and re assemble. Then T into the coolant line. Then, I'd probably discover that when I turned on the water, most of it went out the jet intake, so I'd block that and discover that most of it was going out the thrust nozzle so I'd block that (allowing some to flow so that everything is cool in the jet housing.

That could work, but remember "I have destroyed a lot of good stuff in the last half century" but I have also fixed a lot of broken stuff that "they" said couldn't be done (usually because I broke it first).

The first thing I would do is get the service manual or at least go to the local Jacuzzi authorized repair facility and ask what they do to get around this problem. Asking us, would show questionable reasoning abilities on your part. I mean really, would you trust the knowledge and advice of a news group when four out of five responses don't address the problem or just keep saying you cant do it?
Go slow and Good luck
Shawn

"R Mac" wrote in message news:TRJve.102800$El.64220@pd7tw1no...
| Does anybody know if its ok to run a Jacuzzi 12yj jet in the driveway to
| tune up the engine? Is there any seals that need to worry about running dry?
| If so is there a way to run water to the critical parts?
|
|

Ok, Let's try this again...
Yes, it is OK to run, with a few caveats.

#1) Be sure you have greased the bowl, and thrust bearings, but then
you should be doing this every time it goes out anyway (easy to forget
that bowl bearing, ever priced a Jacuzzi shaft? 9-Bones+ IF you can
find one. Let's not burn that up by forgetting to grease the bloody
thing!)

2)be sure you have flushed any "road garbage" out of the impeller.
Remove inspection cover, and garden hose it out. The YJ is an axial
flow pump, and not too prone to road rocks eating up the wear ring, but
still a good idea. Anyone using a mixed flow impeller has more of a
problem with "road junk" getting into the intake. This is still a
problem when you first put the boat in the lake too, but the water can
quickly wash the debris away.

3) Engine cooling is drawn off the pump bowl, through a nipple fitting
on the Left side of the suction piece (as you look backwards from the
front) You should see a 3/4" hose coming off it. Get a garden hose
repair set (both the connectors) attach the female end toward the
ENGINE "T" fitting, the male on the pump bowl. I use the heavy-duty
style, that attach with real hose clamps, not the crimp-on wally-world
59 cent ones. To run the engine take the fitting apart, and attach your
garden hose to the engine side, turn on water, and start engine. Works
great!

Be sure to turn the water off when the engine is not running if you
have a thermostat installed (most do not have a thermostat.)

Also works to flush contaminated/salt water from engine.

It is a good idea to consider is to add a pressure regulator to the
line. Especially with Olds engines, the excessive water pressure leaks
past the gaskets and contaminates oil (causes milky looking oil). Car
engines like 14-35 PSI in their cooling systems, not the 100-150 PSI
developed in jet drives.

Hope this helps


Oh, yes, and don't forget to reattach, and tighten the connector before
putting the boat in the water... or you get a big, wet surprise.