Run'n that jet out of the water

On those days when you just want to here that big V8 idle and echo through the neighberhood or just to make sure everything is good for that lake run a thought comes to mind... Can a jet run out of the water? If so for how many minutes? I seen in past forums guys say to connect a garden hose to the engine to keep it cool but how about tht jet??? AntRant

I've been told to never run the jet out of water. I've only fired mine out of water for a second or two, just to be sure it'll fire once I get to the water. I've been told that running the pump dry can cause many problems:wear ring damage, burnt bearings and bushings, burnt packing rings and seals. I'm sure some of the other guys can give you more specific details on why not to do it.
My advice: Don't do it!
Hope this helps.
John

NEVER RUN YOUR JET OUT OF THE WATER if you don't have to. If you need to run it, first thing I would suggest if possible is to remove the u-joint between the jet and the motor. Then you can run your motor, rev it, do whatever and not have to worry about hurting your pump. If you can't do that, and you just want to idle the motor for a minute, then take a garden hose and put it through the nozzle of the jet until it's just inside the bowl veins (about an inch) Turn the water on full and you should see water running out of the intake and out of the nozzle. Go ahead and start the motor, but do not rev it. Again, try to avoid running a pump out of the water even if you do the garden hose route. Best case is to disconnect the pump from the motor. Good Luck, I hope this helps.
HBjet
[This message has been edited by HBjet (edited November 22, 2001).]

Excuse me for being a little contrary in my opinion here, but what exactly is going to happen? The front end is lubed by a grease fitting. The wear ring does not contact the spinning impeller. The tail bearing runs in an oil bath. Not knowing any better, I have run both a Berkeley and a Jacuzzi on the trailer for an hour or more, and nothing happened at all. The tail bearing area and the front gland got slightly warm, no different than any other spinning shaft with bearings and seals. The boat works fine, so what's the worry?

I'm with Jim on this one...................
I've run my American Turbine at idle for extended periods of time and the Jacuzzi befor that with no problems as well!
I wouldn'r rev 'er up or hold RPMs for any length of time, but a few BLIPS of the throttle don't seem to matter either.
http://www.goldenplasma.f2s.com/foru...ifferent05.gif
Just my experience and opinion......
[This message has been edited by XClutchboy725 (edited November 22, 2001).]

About four months ago, I asked Greg Shoemaker the same question. His reply was never run it out of water for very long, but a minute or two when necessary probably won't do much harm. We didn't get into the specifics, because, as always he was very busy. DJ makes a valid point, but I always play it safe when in doubt. Fortunately for me, I live only twenty minutes from the lake. http://free.***boat.net/ubb/smile.gif

I'm confused.....I just picked up an Apollo with a Berkley A impeller and I was told by the guy it would be ok to run out of water. But not for extended periods of time because the motor doesn't have a radiator like a car if it is out of water. I mean the only thing I would need to do really is just start it up and wake the neighbors up get the oil warmed up a bit then change it. And so far just by going through this particular posting it's 50/50 if ya ask me. I'm not trying to put anyone down but does anyone know the truth?? Tell me, because I can handle the truth!!

The pros say don't. After they say don't, they say to plumb a "Y" fitting between the pump's motor outlet (on the inside of the boat unless you have a set back pump) and the motor. On each of these Y's, you should have a valve to control water flow. Hose should be on all the way. A small amount of water should be sent to the rear, going into the pump. More than a trickle, less than a full-on gush. The rest of the water should go to the motor. This is for a variety of reasons.
A) If you run through the transom headers, you will cook the flappers out of most of them by running them dry for any period. And, if painted or powder coated you will heat them up really fast and trash them. If you have OTT headers, it will not matter unless you get over 2000 rpms anyway, but see "B" why you should do it anyway.
B) Your engine needs to be cooled. This will cool your engine.
Two things regarding this.
1) NEVER turn a cold hose on a hot engine. You could crack the block immediately. Turn the hose on first to gauge flow. It should be coming out of your water outlet and the jet. (probably the grate, and a little out of the nozzle)
2) ALWAYS shut off the hose before you kill the engine (just before, not way before) This will prevent #1 from happening.
The pump is water-cooled and lubricated. The rear bearing is lubed, and I know the wear ring should not touch, but somehow it does and gets hot. I think that the water pressure around it keeps it from touching.
If you have an extraordinarily loose pump, I could see this not being an issue. A full race pump is set up really tight. Even starting it for a second could bring you to zero tolerance just because there is no load on the pump to pull the impeller into position.
Like HB jet said, the best move is to undo your u-joint. Just make sure you remove anything from your motor that could flop around and do damage.
Though expensive, and space consuming, this is one thing that a jetaway is really good for. You can release the union and do whatever to your motor, and disengage the jet completely in about two seconds. I will be getting one for the pickelfork for sure.

Originally posted by DetroitJim:
Excuse me for being a little contrary in my opinion here, but what exactly is going to happen? The front end is lubed by a grease fitting. The wear ring does not contact the spinning impeller. The tail bearing runs in an oil bath. Not knowing any better, I have run both a Berkeley and a Jacuzzi on the trailer for an hour or more, and nothing happened at all. The tail bearing area and the front gland got slightly warm, no different than any other spinning shaft with bearings and seals. The boat works fine, so what's the worry?
Well, I'm definitely not the authority on the subject but I'll point out a couple of areas that might be of concern. First is the warmth you feel on the front bearing and gland area. Yes it doesn't seem to get too warm, but remember that the packing material is designed to be cooled by water forced into the packing by the pressure in the intake. Without that water, you could cook the packing and be looking at a leak or worse.
The second issue has to do with a couple of things but basically it relates to the impeller and wear ring. If you look at your jet, there is quite a bit of un-suspended area on the input shaft. The reason the design doesn't need another bearing in the middle is because when the boat is in the watter the impeller ballances itself with the water that it loads. Without that water you will incur torsional loading on the shaft and depending on your impeller/wear ring clearance, you could end up torqing the impeller into the wear ring on the side of the pump that falls in the direction of the shaft rotation. This would be done by reving the motor out of the water. The last issue is the balancing of the impeller(or lack thereof) and the front and rear bearings. Since the impeller is not ballanced it can setup odd wear patterns for the bearing surfaces on the shaft when run out of the water. Once again, the impeller needs to be under load to balance itself While this probably wouldnt happen after one quick 2 minute out of water situation at idle, it can happen.
The bottom line is that if you spend time and or money to ensure that your tolerances are tight inside the pump, you're probably not going to risk ruining the work that has been done over running the boat dry. If you do have to run it out of water, make sure you dont do the 0-5000 RPM drill on it as you're sure to cause problems in the long run.
Just my $.02,
Chris

Now as for disconnecting it completely from the u-joint going to the impeller I'm guess it's just like removing a driveshaft from a RWD vehicle am I not correct? Do you also have to make marks on the u-join and where it connects so it lines up like it did before you removed it, is there some kind of balance as for weights?

I have a 455 with H2O injected headers. To be on the safe side, I installed a gate valve
between the water outlet and the pressure/T-valve. This way I can control the amount of water to the headers. I put it at the front of the engine so it and the throttle can be controlled easily at the same time. I'm in the habit of disconecting my pump if planning any long "dry" runs. At the same time you can hand spin your impeller and feel
for any thing weird.{bearing noise,slop}

I also have a t handle valve for water for my water injected bassett headers pretty interesting stuff. What is the purpose of having water injected headers anyway?

I have to agree with Flat Broke. When I jacked my pump up at Havasu (sucked rocks) and took it to Greg Shoemaker, the shaft was twisted, so that had to be replaced. When Greg was showing me the shaft, (the boats, not his) he told me that it looked as if the boat had been started on the trailer too many times as there were scoring marks on the shaft. -DD out

we have a short winter here in texas, so I never do anything to winterize the boat except drain the water out of the block in case i forget and leave the garage open too long on a sub-freezeing day. So to keep the fuel from going bad in the carb I start the boat for about 15 to 30 seconds every week or so. Been doing this for 20 years spred out over 7 differant jetboats and never had any trouble or damage. And its 100 miles to the closest lake, so I start it before leaving for the lake for a few seconds, BUT, if I,m going to run the motor any longer than that I'll uncouple the motor from the pump, hook up the water hose and you can run the motor all day(or till the cops show up).
There might be a small risk doing this, but who wants to get to the lake with a boat that wont start?

I use to do the same thing run the motor on the trailer periodically just to keep it from setting up during the winter. But if you talk to some of the pump guys across the U.S. they will tell you never to start it dry especially if you have a pump set up extremely tight. Because this just throws out all the tolerances you worked for to make it that way. Yeah it might not hurt the pump but you are loseing the tolerances you set up for and then loseing effeciency. If you run alot of valve spring press periodically during the winter I roll my motor over with a ratchet to keep the springs from setting is the same position all winter. But this is just my opinion there are many more out there. Later

whewwww scoring marks on the shaft thats not good!

Look, a pump was designed and made to run in the water, not on a trailer, dry. There is no reason to run a pump out of the water. If you really just want to hear the motor run because your missing the water, disconnect the pump and rev away on the motor all you want.
HBjet

When I got my pump back from MPD, I was told to never run it dry. Especialy because I have a Jacuzzi WJ which uses a polymer/plastic wear ring unlike the Berks and AT/Dom, etc which are stainless if I remember right.

You can spend 1200.00 and buy a Jet-Away from Duane Oblander in wichita kansas at Hi-Tech performance. Works great if ya have to do out of water tuning on a blower motor or other HP engines!
Always be sure ya have a water supplied to the engine block. I have a "T" right after the pressure releif valve where I hool up a water hose just before I fire mine up to work on it at home b4 we go to the lake--if ya do this in the winter months--be sure ya drain the block again and drain the headers--or CRACK!

crzyhotrod, whats a Jet-Away??

http://hi-techperformance.com/images/IMAGE12.JPG
[This message has been edited by PC Rat (edited December 29, 2001).]

Great safety device.
http://i2ff.com/nascar/rank.php?id=986360
[This message has been edited by LS55 (edited December 30, 2001).]

pcrat, I still don't get it....

That is a picture of a unit that connects on the drive line allowing you to "disconnect" the drive line this way when you run your engine you wont be spinning your pump!
Jesse

Wish I had a jettaway.
SJ

I agree with froggy on what he said. I have my cooling system plummed with a "y" fitting so you can hook a garden hose. The water goes into the jet right where the impellor and wear ring are to keep it cool and also to the engine for cooling. If you don't have this fitting I think running pump dry the wear ring and impellor will heat up. I'm curious how you guys that don't disconnect the drive shaft and say not to run the pump out of water set your engine timming? I have a small plate I can take off to lube u-joints but It would take all day and alot of nuckle busting trying to disconnect the drive shaft just to fire it up. I say if you have this fitting for garden hose your save to run it. just my 5 cents worth. http://free.***boat.net/ubb/smile.gif

forget about the pump. Just fire that baby up and wrap the throttle to your hearts content. I wish we were neighbors so we can put a brick on the gas pedal have some beers and listen to the sweet sound of big block for about an hour or so. Although you wouldn't want me to wheel over my Boston Whaler and show you some real exhaust notes.

Originally posted by DOHARA:
I'm curious how you guys that don't disconnect the drive shaft and say not to run the pump out of water set your engine timming? I have a small plate I can take off to lube u-joints but It would take all day and alot of nuckle busting trying to disconnect the drive shaft just to fire it up. I say if you have this fitting for garden hose your save to run it. just my 5 cents worth. http://free.***boat.net/ubb/smile.gif
Well if you really must know. I installed the engine without the driveline for break in and base timing setup. After all of that was done, I pulled the mill, hooked up the driveline and droped it back in. The rest of the tuning was done on the water. If it was something I didn't want to tackle afloat, I pulled the boat into the parking lot and roasted like a pig while I fixed the problem. Drop the boat back in the water to test it out. Just pack up all of the tools you can think of and make sure you have some help. Sure its a pain in the ass, but a complete blueprint job isn't cheap. My.02
Chris

i wouldnt do it i learned from an impeller change about 5 years ago damage cnn occur fast.now i disconnect the driveline takes about 5 min.

Ok I am gonna bite on this one, I run my salt water cooled motor in the Great South Bay and the Atlantic Ocean, I have the fresh water inlet set up with the t-fitting and the 2 valves, as per my conversation with the guys at CP performance . Its the only way I can run my motor for 10 minutes to flush out that nasty salt !!, So which is worse ? run on the trailer or not??

There's much controversy about this topic.This is long so stay with me...Here's my view on it.The rear of the shaft is in an oil bath,(certain makes),the front fo the shaft has a lubed bearing.Now the packing seals or ropes do need water to cool and lube them so the shaft won't become scored...UNLESS...ya use GFO fiber packing there a dark grey graphite type of braded rope that a good friend of mine turned me onto years ago (about 5-6) this is a virtually dripless setup!And I don't see a mark on the shaft. Anyhow and as far as the Impallar to wear ring clearance,It seems to me it dosent matter if ya have .001 thou. or .035 thou.....clearance is clearance, unless your bowl bearings are so shot your shaft is sagging! I've just taken my pump apart this past month,the clearance's are exactly the same,.020 Imp to wear ring shoulder,and.010 per side of Imp. to wear ring,nothing has changed...And I'am one who dose run my motor out of the water for the (shortest)amount of time.With water from a garden hose.Sorry for the long reply,but I feel that ya can do more damage to the Imp.+ wear ring by useing reverse to pull yourself off a beach,something I NEVER do,but yes I wash down the inside of the pump to remove any grit from towing the boat home and hook up a hose to it and make sure the damm thing starts before I leave the house on my 20 mile trip to the water.It works for me.Wheeew that was the longest post for me.

i have a berkly jet in my boat and love to hear that engine rumble when im at home. Ever since i messed my pump up by wearing out the wear ring and the housing around it buy running it out of the water i have never ran it out of the water again. the pump was just built befor that not even 7 hours on the pump yet. i even used to run a garden hose to the pump around the wear ring area. i would never even rase the RPM on the engine. I wouldent chance it!!! just run it at the lake were it belongs. lates