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Boating => Shallow Water River Boats and Jet Boats.. => Topic started by: gaspergou on January 26, 2013, 05:37:55 PM

Title: jet pump woes
Post by: gaspergou on January 26, 2013, 05:37:55 PM
...so I pulled the jet pump off my outboard; three of the five bolts that hold the bottom of the lower gear case housing on had come loose, so that while under power, water would squirt of of the gear case connection (just above where the jet pump attaches). One of the bolts was stripped out, so I drilled and tapped the socket. That's tight now, but I now can't get the damn pump to reseat.

Any thoughts or suggestions?

Title: Re: jet pump woes
Post by: gaspergou on January 26, 2013, 06:25:11 PM
Disregard previous. I had apparently neglected to cuss enough to scare the living shit out of the motor, the dog, the neighbors, and possibly folks in the next county over. After solving this issue, cracking a beer, and trying again, the pump slid right into place.

Title: Re: jet pump woes
Post by: jarrod white on January 26, 2013, 07:07:08 PM
Nice , all problems solved at once
Title: Re: jet pump woes
Post by: Glenn Hawkins on January 26, 2013, 08:09:29 PM
Sounds like many of my projects. ;)
Title: Re: jet pump woes
Post by: MikeA on January 26, 2013, 09:06:25 PM
Any crawdads in there?
Title: Re: jet pump woes
Post by: gaspergou on January 26, 2013, 09:12:19 PM
Nope! ;) 

though I was surprised by just how good of shape the impeller was in...
Title: Re: jet pump woes
Post by: MikeA on January 26, 2013, 09:21:54 PM
Some folks like crawfish etouffee. I prefer crawfish puree.  ;D
Title: Re: jet pump woes
Post by: jladdsmith on January 26, 2013, 11:56:25 PM
This was a good thread. Woe's you, not me this time.
Title: jet pump woes
Post by: Steve H on January 27, 2013, 09:20:52 AM
Nice work Dave. Sounds like my style of project.
Title: Re: jet pump woes
Post by: gaspergou on March 19, 2013, 03:56:04 PM
And without a happy ending.

So... I have a Mariner 20/25 jet. It's been great, until I got a batch of bad gas last fall and dosed it several times with carb cleaners trying to solve the rough idle and starting difficulties without resorting to a full carb teardown and cleaning.

While messing with that, I noticed that one of the five bolts that holds the jet pump to the motor had stripped out and the pump did not fit flush (water would squirt out of the gap between motor and pump while running), so I pulled the pump off, drilled and rethreaded the socket and fixed that problem. I water tested it -- it was peeing when I started it up, but the pump must have stopped after I turned away. I didn't realize it until I noticed a funny smell about a minute later -- I immediately shut it down and paddled the ~75 yards back to the ramp.

I just did a compression test and got 95/90, which makes me think I toasted the powerhead. Has anyone had a rebuild done on a similar-sized jet? What kind of price range should I expect?  If it's too bad I might try looking for another motor to drop my existing jet pump onto... but since its an older motor that might be tough.

Thoughts? Opinions? 


 
Title: Re: jet pump woes
Post by: MikeA on March 19, 2013, 04:16:37 PM
What should the compression be? 90/95 doesn't sound that bad to me.
Title: Re: jet pump woes
Post by: gaspergou on March 19, 2013, 04:42:35 PM
125-150 says the service manual.
Title: Re: jet pump woes
Post by: MikeA on March 19, 2013, 05:46:17 PM
Run the piss out of it.
Title: Re: jet pump woes
Post by: lawnman on March 19, 2013, 07:53:34 PM
It all depends on what happened?  When you pulled the spark plugs did it have any medal on the electrodes?  You could have blown a head gasket (best case senerio) warped the head, worn out the rings, burnt the exhaust valves.  All are pretty easy to diagnose if your handy with engines.
Title: Re: jet pump woes
Post by: lawnman on March 19, 2013, 08:00:21 PM
Depending on how mechanically inclined you are I would at least pull the head off an inspect the damage.  It's not rocket science and the only tool you will need that you may not have would be a torque wrench.  Once the head is off you can easily see if the cylinders are scored or other problems.  How long do you think it ran hot?
Title: Re: jet pump woes
Post by: jarrod white on March 19, 2013, 08:02:55 PM
replace water pump and new plugs and run the piss out of it.... I would say much more than that and I would be on the hunt for a new motor. I have done the rebuild on the older motors before and it never seems to end very well. My .02

                JW

If you decide you want to tear it down, bring it with you next time you are down.. I have a shop and all tools if you don't
Title: Re: jet pump woes
Post by: jladdsmith on March 19, 2013, 08:03:18 PM
Dave,

I've had a lot of bad luck with outboards.  Cooked bottom cylinder, blown powerpacks and on and on.  Literally thousands of dollars later, I can admit now that my folly was in hiring a shadetree mechanic.  We've since parted company.

Like you, I tried to do a lot of work myself- most all of that work was successful, but it was simple stuff that any idiot could do with the right tools. 

I've replaced every electrical component in my Johnson 40, according to Maxrules, SELOC and whatever other resources are out there.  Just disgusted thinking about it so I'm going to quit now. 

The worst part is the general shit-nature of a ruined trip.  Women, buddies, fish- whatever.  And the whole time knowing that you've just been screwed out of money, and that you really tried to give everybody a good trip.

Rant over.

I'm going to buy a new motor with a warranty.  There are a lot of guys who get decades of good service out of an older motor.  Just didn't work out like that for me x 10.  What pisses me off so bad is that this Johnson is 20 years old, but less than 100 hours!  I'm the second owner, knew the first owner as a Grandad, and he was an engineer so followed everything to the letter.  I now use the piston as an ashtray. 

Getting sick again.  Better luck with whatever you decide. 

Damn.




Title: Re: jet pump woes
Post by: MikeA on March 19, 2013, 09:52:04 PM
There are few things in life I hate worse than an unreliable outboard. Run it till it blows, then go to the bank if you have to and slap a new one on and your good for a long time. An outboard is what makes Dave, Dave. Splurge on yourself.
Title: Re: jet pump woes
Post by: grumpy on March 20, 2013, 07:31:12 AM
replace water pump and new plugs and run the piss out of it....                 JW


Upstream at that ;)
Title: Re: jet pump woes
Post by: bee on March 20, 2013, 05:19:36 PM
I am afraid to even look at my impeller.  Some pf the literature talks about how easy it is to refile thr front edge of your impeller.  Scares me to even take the thing off even though i have all the replcement or duplicate keys and pieces to put it back. Thrown a lot of gravel out the back of that pump.
Title: Re: jet pump woes
Post by: MikeA on March 20, 2013, 05:38:00 PM
I am afraid to even look at my impeller.  Some pf the literature talks about how easy it is to refile thr front edge of your impeller.  Scares me to even take the thing off even though i have all the replcement or duplicate keys and pieces to put it back. Thrown a lot of gravel out the back of that pump.
It's easy. I've had an issue where mine blew a seal where the grease goes in (be gentle pumping grease into these things when it's cold out). I had to completely disassemble the pump to get to the seal. It's really not a big deal at all. Take photos and notes as you pull it apart.  Every year I remove the grates and file them sharp like a knife, then sharpen the impeller. It helps alot. I'll be glad to help you with it if you want to tackle it sometime.
Title: Re: jet pump woes
Post by: Dub on March 20, 2013, 07:36:54 PM
Why don't you drive down here and help me patch up my boat?  :P Just kidding......But it's good to know you are a jet boat mechanic.
Title: Re: jet pump woes
Post by: MikeA on March 20, 2013, 07:49:35 PM
I can do that too. You got two spots the size of a quater,, we could fix that up in about 10 min. Then I can take you out and show you how to run the boat.
Title: Re: jet pump woes
Post by: David L. Darnell on March 20, 2013, 09:04:47 PM
what motor did you go with Dub ?
Title: Re: jet pump woes
Post by: Dub on March 20, 2013, 09:24:36 PM
I can do that too. You got two spots the size of a quater,, we could fix that up in about 10 min. Then I can take you out and show you how to run the boat.

And one 4 foot long gash that took the gel coat off. It's about 1" wide by 4' long. Anyway I'll have her up and running by monday if Line-X can fit me in. Im fix'n the fiberglass and then the line-X goes on. Yeah....I think I found the lower limits of draft. There is a lot to learn about a Jet and the river or water levels (lack there of) the boat is really assume it's the captain that needs work.

David, I got a 25hp Jet mercury. It's factory jet.
Title: Re: jet pump woes
Post by: David L. Darnell on March 20, 2013, 09:28:15 PM
I had a 25hp 4 stroker on the metal boat I just sold, did good but as my wife said why have a 25 when they make a 40, curious to see how the 40 does on the Supreme, they do great with 25's.

With the 40, I can get in it when I need to and throttle back and run almost as fast as wide open with less fuel.
Title: Re: jet pump woes
Post by: Dub on March 20, 2013, 10:22:22 PM
I bet the 40 will be great. Ill have to hit you up for a ride sometime.
Title: Re: jet pump woes
Post by: MikeA on March 21, 2013, 06:06:51 AM
I can do that too. You got two spots the size of a quater,, we could fix that up in about 10 min. Then I can take you out and show you how to run the boat.

And one 4 foot long gash that took the gel coat off. It's about 1" wide by 4' long. Anyway I'll have her up and running by monday if Line-X can fit me in. Im fix'n the fiberglass and then the line-X goes on. Yeah....I think I found the lower limits of draft. There is a lot to learn about a Jet and the river or water levels (lack there of) the boat is really assume it's the captain that needs work.

David, I got a 25hp Jet mercury. It's factory jet.

If your gonna line x it you don't have to fix anything. You might want to spend some time getting to know the boat in a safer location though... I won't say I told you so, but I told you so.
Title: Re: jet pump woes
Post by: bee on March 21, 2013, 07:02:55 AM
Thanks for offer Mike.  Might call someday.  What is approximate labor time frame to take it off and refile grate and peller??   

Also what curious what you folks use for grease guns. I have been putting the very expensive merc factory grease.  Smaller grease tubes aee about four inches long -+ and less than two inches in diameter.  My current gun is designed makes it very difficult toload the tubes ?  What brand small grease guns are you guys using??
Title: Re: jet pump woes
Post by: MikeA on March 21, 2013, 07:37:53 AM
That job takes a couple hours. If they are bent you can hammer them back flat on a vise. Then sharpen them on a grinder. Pretty easy job.

I just use a standard grease gun and waterproof grease. It's recommended that you  use a tube and force the grease in by hand. This would have prevented blowing the seal on mine.
Title: Re: jet pump woes
Post by: Bfish on March 21, 2013, 08:28:13 AM
This use to be free (might be a hard copy out there somewhere) and is helpful:
http://shop.backwoodsanglertv.com/30-Minute-Preventive-Maintenance-For-Your-Jet-Boat-Motor-30-minute-pm.htm

Outboard Jets recommends the jiffy hand held for lubing:
http://www.outboardjets.com/faqs.php#10