Took my dad's jet sled with a 90/60 Mercury jet out last Sunday and managed to suck up some rocks into the intake. The grates are all bent, so it allowed some golf ball sized rocks to get in. One of the rocks lodged in the impeller area, which prevented the motor from turning over, so I took the grate off the bottom and put a crescent wrench on the main nut and turned it until the rock popped loose. After getting all the rocks out of the motor, I noticed it's only got about half the "get up and go" it had before. The impeller blades are noticebly dull and dinged up. Not sure what they looked like before the rocks were sucked up. The housing around the impeller(s) is/are noticeably grooved.

I'm thinking I should take the impeller(s) off and file the edges and put them back on. Are the impeller edges most likely the problem, or is there something else I should be concerned with? Thanks for any help!

Straighten the grates and file the edges from the inside of the blades and not the outside. Careful to not overfile too.

Or get a new 4-blade stainless steel impeller and new liner and you should be golden.

Yep, the liner might need to be replaced too if it's really beat up. Also, you can adjust the spacing between the impeller and the liner by moving the spacer washers up or down. You can check the outboardjets site for guidelines.

Been there done that. What cobble said.Good luck,


SZ

1. Take the lower housing off.

2. find something to use, with a hammer, to drive the "pin" out that holds the grates in. I used a big nail, that I ground the point down.

3. Straighten the grates.....I've done the filing bit, that Cobble Crusier mentioned.

4. If liner, has lot's of "grooves"......get new one.

5. Make sure you count the number of spacers, if you take impeller off, write the number down......so many on top, so many on bottom.

6. If the edge of the impeller is chipped and looks like it would be filed, do so.....I found this for you....

http://www.outboardjets.com/pdfs/IMPELLERSHARPENING.pdf

http://www.outboardrepairs.com/topics/005416.html

7. If any big chips.......buy new......Stainless steel is the way to go....many new motors now have the stainless steel impeller, right from the factory. Choice is either a 3 or 4 blade, impeller, in general a 4 blade....more get up and go but less top end.

Good luck........I have a feeler guage that is 8 -10" long, that makes it easy to check spacing of impeller to liner. Too much space, poor performance......... to little, engine might not start at all, to tight or if could wear a groove in the liner....right away.

Liners are $40+ ...... impellers ...... spendie!!!!!!!

Thank you, DrifterWA. Lots of good information. I'll be working on this this weekend and I'll post a report of how everything turned out.
Thanks again!!

#8 Tell Dad sorry

LOL

Dad was there when I sucked up the rocks.... he helped remove the foot and pull rocks out....

We're learning together....

Also, if you are really unlucky, the shaft and seals could be hosed too. If, after you fix the impeller, lining, and grate vanes the motor still has lost some giddiup, you might notice a strong vibration. If that happens, big bucks may be required. Good luck!

I personally wouldn't put a SS impeller on a 90/65... especially if it's a 4 stroke. You can google search the reasons why.

Take the impeller to Three Rivers and have them sharpen it for you. Get a new liner while you're there too. Shim it correctly and you should be good to go.

Sucked many rocks over the years... But when you describe "half" power, does the boat still get up on plane?

I once hit hard, sucking rocks and after cleaning it out I had about "quarter-half" power. Took it in to find I had screwed the computer up, about a $600 fix...

I've had my shaft shear off, but that just randomly happened when out fishing one day, that's about $800. Just chalked that one up to wear and tear over the years...

I can't imagine you fried your liner or dinged your impeller up too much from a few rocks... Although the grates are there for a reason, some bent grates aren't going to diminish power much. I ran mine for years with warped grates....

Does it appear to have about a credit card width space between the liner and impeller? If not, shim the impeller to where you have that proper gap.... Big problem with those smaller motors if that gap is much larger you lose proper suction... Personally, I think this sounds like your problem. The bigger motors are more forgiving, you don't notice that lack of power as much.... When you get down to two shims left on the bottom of the impeller, that's when I'd suggest a new liner...

Sharpening the impeller is easy, many step-by-step instruction guides on the internet...

Keith

You might have a couple of small rocks caught between the exhaust liner and the wall. Look at the back of the pump outlet. If you can see any small rocks caught between the exhaust liner and the outer housing, you've probably found about 90% of your problem. You can usually work them out with a pair of needlenose pliers.

I was reading this thread on break today and thought I would ask Glen Wooldridge. Here are his thoughts.........

alanmikkelsen- You are correct about rocks between the exhaust tube and housing.

The 4-blade works great with the 90/65. It doesn't lose any top end speed even with less RPM's which are sometimes confused with less speed. The 4-blade stainless is also better at getting a load up on plane. It stands up much better to rocks and wear.

As alreay stated, shim to .015 with a new liner if yours is badly groved.

Glen

Good to know Danny... thanks!

I think I see a SS impeller in my future on my 90/65.

Glen's pretty soft spoken till you get him talking about jet boats.

1. New liner
2. New impeller
3. Beg forgiveness.

Liner? I thought it was called a wear sleeve?

Anyhow, it might very well be a case of "death by a thousand cuts." All of the aforementioned issues do affect performance (grooved/worn wear sleeve, dull/damaged impeller, bent intake grates), to what extent depends on the nature and significance of the damage. You might also have a look at the bottom of your hull, especially if you have a tunnel hull as dents and deformation can affect performance as well. I'd be willing to bet a new wear sleeve and straightened intake grate fins will sort you out.

The glacial silt in a lot of the rivers in AK does a number on both aluminum impellers and wear sleeves. If you put more than about 100 hours on your jet boat in silty rivers, you can expect aluminum impellers and wear sleeves to last about two seasons before performance very notably starts dropping off.

"liner" is Outboard Jets, San Leandro, CA nomenclature.

Aha.

What do those guys know anyhow.

Half power might be inaccurate, probably has 80% of it's "pre-rock sucking incident" power. It gets up on plane, but doesn't have the high end speed. Like 15 mph instead of 25 mph....

Nicked up impeller, liner worn, replace and shim, get back to us.

Heres a pic of the bottom of the foot. We tried straightening the grates with pliers, but couldn't do a very good job.

[img]http://i897.photobucket.com/albums/ac180/Audball0770/footgrating.jpg?t=1355688063[/img]


There's a rod holding the grates in that we tried pounding out with a nail, but it wouldn't budge. Maybe I just needed to hit it harder, but I didn't want to break something....

http://i897.photobucket.com/albums/ac180/Audball0770/footcloseup.jpg?t=1355688072

Here's the impeller....couldn't figure out how to loosen the main nut holding the impeller on.... didn't know which way it's threaded, and was afreaid of breaking off a bolt....

[img]http://i897.photobucket.com/albums/ac180/Audball0770/impellercloseup.jpg?t=1355688072[/img]

Tried deburring the edge of the impeller...difficult to do while it's still on the motor...

[img]http://i897.photobucket.com/albums/ac180/Audball0770/Impellerverycloseup.jpg?t=1355688080[/img]

Here's the liner (wear ring)..... has some pretty deep grooves in it...

[img:left]http://i897.photobucket.com/albums/ac180/Audball0770/wearringgrooves.jpg?t=1355688088[/img]

And finally, here's a view looking into the pump nozzle....looks to be clear of rocks....

[img]http://i897.photobucket.com/albums/ac180/Audball0770/exhaustport.jpg?t=1355688063[/img]

1. You just can't straighten the "grates", without having them off/out of the shoe. Then you can use a vise or just hammer them straight.


2. Drive pin out......bigger hammer, it will drive out......might have to have something "about same size as the pin".....nail always worked for me........try find one side, then the other....it will come out!!!!!

3. Jam a piece of wood, next to the impeller......I have a closed end wench that fits this nut........Righty tighty.....lefty loosey

4. Can't do, impeller, while in boat.....has to be out......

5. NEW LINER ..... doesn't look good to me..........BUT I've seen them worse.......and I don't even work in the business.

6. Hey....good news "the nozzle looks good"...and the impeller looks like it can be made to work. I lucked out, at a garage sale years ago....got 4 or 5 big files and 4 big wenches 7/8 - 1 1/2.....they have saved my butt many times over the years.

Wish I lived closer....I'd help out...

If a outboard marine shop....had all the parts.....and the person doing the work....stays "on task"....whole process....less than a hour.


No one likes to spend $$$$$$$$ but sometimes "for piece of mind" new parts are just nice.

Ohhhh one last thing.....get an extra "lock washer".....the one with the ears/tabs on it............doesn't cost much, sooner or later...you'll break a tab off.......

Good luck.......

Go Seahawks !!!!!!!

Should have bought all the makings for spinners.....I might have gone for a drive.........lol.....just kidding....

Yep! XACTLY what drifter said.

Thanks to all for your help. I am the dad/owner of boat/guy who helped Audball suck up the rocks. We will follow your advice and let you know how it turns out. We WILL get it fixed, even with loss of cash; not sure i could get by without the jet.

Good point, I've been in that situation myself Drifter!!

Roger66:

I'm like you......need to have "jet".....while I still bank fish, in the summer, the vast majority of my fishing, September 16 to March, is in jet boat water.

New liner, filed impeller, grease everything, make sure on the .015 spacing. That cost would be less than $100.00

Cost goes up, if new Stainless Impeller, or if shaft in bent, or if a shop does the work. You might want to call the good folks at Wooldridge, they have a vast amount of knowledge on jets/ and impellers.

Good luck !!!!!!!

Ok,
Today we got the nut off that holds the impeller on (thank you DrifterWA ). Took off several washers. Now, I'm wondering if we need a puller or similiar tool to take the impeller off. I pulled on it as hard as I could and it wouldn't budge. There seems to be something wedged next to the shaft...does that come out somehow?
Here's a pic of what I"m talking about....
[img]http://i897.photobucket.com/albums/ac180/Audball0770/impellerhubcloseup.jpg?t=1356230291[/img]

[img]http://i897.photobucket.com/albums/ac180/Audball0770/impellerwideangle.jpg?t=1356230295[/img]

Also I put Liquid Wrench on the pins holding the grates on the foot, and used a bigger hammer and a heavy punch, but still couldn't budge the pins. Can't imagine I need to use a sledge hammer.?... Any help appreciated. Thanks

That thing is called the key. It keeps the impeller from spinning on the shaft.
Do you have 2 pry bars? They don't have to be big ones... just the typical 16" ers you can get at Home Depot.

Heat the center of the impeller with a propane torch. You don't have to get it real hot and I wouldn't because there's a plastic insert inside it. Place the 2 prybars across from each other and pry both sides simultaneously. The Impeller should come right off.

When this is all said and done, you'll have learned "lot's" .

If that impeller is that tight, then I hope there isn't a bigger problem.

I like the "tap, tap", that Chuck S. mentioned.....might even need more "tap, taps"......

When you start putting stuff back together, grease everything.


Wow....to not getting the pins out.....did you try from both sides?????? I never had any problems on the Yamaha or the Mercury I had......maybe someone else can help out???

Thank you 4Salt, DrifterWA and Chuck S !

Plan now is to buy a new liner (wear ring) and a puller , or couple of pry bars. Heat the impeller shaft and pry off the impeller...

Still not too sure about the grates. I put Liquid Wrench in the holes and let it soak for half an hour then pounded pretty damn hard with a fairly heavy hammer with no luck. Thinking about taking it to a pro to have them get the pins out....

We want to do as much of this as we can ourselves, mainly so we learn how to do it in the future.

Thanks again for all your help guys, I really appreciate it....
Dave

hit it like it owes you a dollar.

Don't worry about the grates just bend them the best you can. Just work on the liners and washers. Rocks don't ready grove the liner most of the time. It's the tork in the shaft and the blades bend and rub the liner a little not much you can do about it just part of the game. Don't get me wrong gravel bars and jets motors are not a good mix.

be careful because even with a propane torch you can melt the impeller Aluminum) unless it is stainless or steel composite.

The little plastic liner for the impeller/shaft likely will need to be replaced due to the corrosion that is holding it on the shaft. Keys are also cheap.

Use anti-seize when putting back on.

Also a little heat on the pin channel should help at both ends of the foot. Or heat it warmer than you can place your hand on and let cool or cool with a garden hose as sometimes this will break the corrosion.

Use no bigger than a 4 lb hammer and a good long pin punch

With how bent your intake/grate fins are, I wouldn't be surprised if they are helping to lock those pins into place. If you can't tap, tap, friggin TAP them out, you might have to sawzall the badly bent fins out to take some pressure off the retention pins.



Be careful that you don't crack the foot if you really start wailing on them, new fins are cheap, a new foot, not so much.

This is a great thread! I have seen fins that bent before and not cause that much reduction in power. Thinking Coley might be right about them holding the pins in. Might be able to pry on them some and get to ease up on the pressure? Anyway if ya get the the new ones the saw out method would be great. I am wondering if the pin itself could be pranged in some way. Might be good to get a new straight one just in case.

I would like to see the impeller and clearance to the liner and liner condition. Loss of power can also be caused there. Those fins are most likely holding the pins in place and are not going to be nice about moving.

+1

Not to mention, larger gaps between them means bigger rocks into the pump next time you hit gravel.

All this hassle with the grates......and getting the pins out....I wonder if there isn't a "used 90/65" lower unit just sitting around somewhere. Might be worth a few phone calls, just to get a price.

I'm real good at spending other peoples money.......but some times its just worth it, to buy good used or new.

Doesn't take much, to cut down the water intake, and thus performance....I'm sure 90% of jet boaters will tell you, what happens to power/performance...when you get 1 or 2 leafs or grass hung in the grates.

Great idea!

You wouldn't even have to replace the lower unit. You could just buy a new shoe if it came to that. I'd try bending the grates back as close as you can and then try the pins.

Sorry....shoe = lower unit, in a jet pump.

Merry Christmas......

Was surfing the net......found the following: Good information..

http://www.fishwithjd.com/2010/05/19/5-tips-to-help-improve-your-outboard-jets-performance/

I bent my fins up pretty badly last year and it was a beotch to get the pins out. I had actually compressed the hole the pin goes through and bent the pins somewhat and that coupled with the pressure of the bent fins had them stuck fast.

I spent a bunch of time straightening and wiggling the fins until they loosened up some and weren't presuring the pins so much. I then found a drill bit the same diameter as the pin and opened the holes back up a bit. Eventually, I manged to free up one of the pins and once one side was loose the other pin came out as well.

I think I used up my yearly allotment of expletives on that job.