I have a jet boat whats the deal on starting on the driveway,,I hear never do it or its ok for a minute or two..or disconnect the u joint...and use the water hookup for the motor..What seal wears out when you do that...???So Can you Or cant YOU..I t really sucks not to be able to toon your boat on the driveway...I have a water hook up for the motor..but my u-joint doesnt push back far enought to get it out...WTF

Sometimes it's impossible to disconnect the driveline with 3 point, or sometimes even 4 point, mounting systems. A lot depends on which driveline you have as well. If theres a PTO adaptor used on the flywheel, usually you can. Especially on 4 point engine mount systems, and sometimes on 3 point systems (I could on Moo, it had a huge access hole in the bellhousing with a body plug in it you just popped out).

We all say "don't run it without it disconnected", but then we all have and do. What it really damages is the wear ring on the impeller and burns the front seal packing. Best solution I ever heard, and use often, is three garden hoses when you cannot disconnect. One to the motor, barely open, really, then two more basically wide open, one stuffed up the rock grate and one up the nozzle. Be prepared to make a mess.........

Ray

Ok im sorry but totally disagree with you guys. First off if your impeller is rubbing on the wear ring you have bigger issues. Correctly set up there is .25 wear ring to impeller clearance. I dont know why people make such a big deal about this. If your run your jet for more the 10 mins on the trailer i would run a second hose down the clean out and thats it. The packings are the only thing that can be hurt because they can make the shaft hot and burn the packings. The only other on to watch out for is if you have water lubed bowl bushings. If you berk still runs oil in the bowl (or grease) than run it.
Matt

Be careful.....The Berkeley type pumps rely on pump thrust to keep the shaft symmetrical to the pump housing, running the pump without this thrust (angular contact double row ball bearing) can cause impeller interference with the wear ring.

Been doing this since the early 80's and have owned more jets than I care to admit to....

Totally depends how the pump is built, I use an RV holding tank clean out wand tie wrapped to the loader (can't get my hand hole cover off). But with a stainless impeller and snug wear ring and snug fitting stuffer, I really don't do it.....Often... It makes a lot of noise and sounds, well, expensive.

Number one thing to do is to spray the intake out with a high pressure water hose to clear any debris that could be in the pump, this could potentially clear small rocks/dirt from the wear ring area and saving you some grief. The intake of the pump is like a street sweeper while going down dirty/rocky roads....I used to use a place mat (like for a kid at the dinner table) duct taped to the intake on long road trips on the race boat, you should see the faces when I pull a 16"X20" picture of Elmo off the bottom of the boat....


GT

Can't speak from personal experience but growing up I use to help my grandfather work on his. Everytime he would change something on the engine we would pull it and to pull the engine out of his boat it only took around an hour or so. Then it was off to the shop to have it dyno tuned. They would get dead on then fatten it up a bit and back in the boat. About a day worth of screwing around and It was about $200 for the tune. Never had engine problems on the water.

SoCalPsd-Corey