Merc Water Pump

[jetwrench]

Hey guys, I hope someone out there can help me with this one. I am new to the motors over 5 HP and have just bought a 35 HP merc. I need to replace the water pump impeller (impellers?). Can anyone give me a walk through of what is involved? I can't seem to locate a manual for this motor, unless I order it from the web, and I don't feel like waiting to get the boat on the water!

I would appreciate any help you guys can offer!

[TONGA]

should be pretty strait forward but before we get started what year is the engine?

[Joe_G]

I just put an impeller in my old Merc outboard Sunday, and much to my surprise, it was fairly easy and it worked! So I may be able to help also. I bought a Mercury Outboard shop manual for 10 bucks at Discount Marine. It covers outboards from 3.9 to 135 HP.
Clymer Publications B719. Like Tonga says, what year is your motor? I can e-mail you the whole procedure if you like.........

[jetwrench]

Thanks guys, the motor is either a 88 or 89. Serial number 6580652. I appreciate the help! I am sure it is pretty straightforward, but just want to make sure I don't mess anything up!

[WALLDADY]

I have changed impellers on my 9.8 Merc. a few times . If you go to the Boat Shop for your parts , give them the serial # , they will look it up on the microfish . That way you will know all of the info neccissary . My boat shop gave me a printed out break down / blowup , of the entire lower unit , FREE . A manual is a very good investment if you intend to do your own repairs and maintanance. If you use your boat in the winter , like for Winter Steelies , an extra impeller and the nec. tools in the tool box , can and prob. will, some day , save a trip . They are easily changed and can be done , with the boat on the trailer , in the parking lot .


Good Luck and Safe Trips ........ Walldady .

[SalmonSlayer]

How often do impellars need to be replaced? How do you know when to replace them? I have a 1991 88 horse Johnson outboard. I don't think they have ever been replaced...should I?

Could this be the problem causing my engine temp warning buzzer to go off sporatically? Usually it goes off near the launch, then I disconnect the buzzer and after a while of trolling connect it again and it is not buzzing anymore.

Thanks,

ben

[WALLDADY]

Salmonslayer , I dont know if there is a time table for replacement . The hole on your motor where the water squirts out is what I use . The way I understand it is , the water squirting out is excess from your water pump . if its squirting hard then your water pump is working well . if its dribbling them you prob. either got something plugging the hole , or its time for a waterpump . And Im not sure about your alarms .


Good Luck and Safe Trips ...... Walldady

[1fife]

try this hope it helps

http://www.bassboatcentral.com/sttips.htm

also and issue of bass and walleye boats showed how also-do a search and find that issue(not sure which one)

[TONGA]

Jetwrench did Joe send you the procedure? if not let me know?

[jetwrench]

Tonga, check your PM's

[TONGA]

Jetwrench did you get it out?

[The Whale]

Salmonslayer, I'd be a little concerned over disabeling my overtemp warning indicator, for whatever reason. There is typically a reason for this going off, could you be "cooking" your motor a bit each time out ? Hope not. May wish to investigate that cooling issue/warning buzzer issue before trouble comes !


Whale :) :cool:

[SalmonSlayer]

Whale,

Thanks for the concern. I would worry more about it, but by the time I get to the pierheads from the launch in St. Joe I hook the buzzer up again and it is not going off anymore. For this reason, I'm thinking it is the impellar just not pushing enough water through the system...although the stream out of the motor seems to be strong. Either way, I'm going to replace that impellar and go from there. It has been 7 years at least on that impellar...launching from the dirty st joe river and trolling a lot in the river plume by the pierheads.

[jetwrench]

Tonga, no luck yet. I am afriad I am going to damage the cast metal shroud by pounding on it too hard. I completely covered the area with some penetrating oil and am going to let it sit for a couple of days and see what happens then. I am starting to get frustrated seeing all the boats on the lake everytime I drive by!!!

[TONGA]

are you sure you have everything unhooked? it should not come out that hard,,I would think a few light taps on a Block of wood should free it up!

[Joe_G]

Hang loose Jetwrench,,,,,I'm gonna type up the procedure for you
now and send it to you via PM. There's a hidden bolt underneath a plastic plug.............

[Joe_G]

Jetwrwench, I added some more tips & tricks in a PM I sent you,
but here's the basic procedure in a nutshell......

Here's what the shop manual says for a 35 HP Merc...................

Step 1: Remove the 2 hex nuts holding the gearcase to the leading edge of the drive shaft housing.

Step 2: Remove the hex locknut from the center bottom of the
anti-cavitation plate. (That should be in a recessed depression accessible only with a socket wrench). If the prop's in the way, you may have to remove the prop.....

Step 3: Pry the plastic plug from the rear of the driveshaft housing. See figure 4. (Too bad you can't see figure 4!)
Unbolt and remove the water pickup or trim tab.

Step 4: Remove the bolt from the water pickup or trim tab recess.

Step 5: Separate the the gearcase from the drive shaft housing.

Step 6: Remove the 2 small nuts on the plastic water pump cover to gain access to the impeller.

When reassembling, put a bit of grease on the top of those long shafts.

[jetwrench]

Thanks guys. I will check for the hidden bolt tomorrow when I get home from work. Gee, you would think that after working on commercial airliners for a decade I would be able to figure out a simple outboard! ;)

[Joe_G]

Well jetwrench,,,,,How'd it go? More than once I've started a repair and ended up
taking it in to the shop.......Hope you had better luck!!!

[SalmonSlayer]

Jetwrench-

I just took my lower unit off last night! I had to unhook the shift lever from the linkage up by the motor. I found this out by consulting a repair manual. It was kinda confusing as to why I needed to take that off, but it was clear once I had the lower unit off! :rolleyes: At first I didn't remove this and I could slide the lower unit down a little, but it would hang up on the shift lever rod. Once I wiggled it around and saw what it was catching on, I knew why it needed to be disconnected.

Is your lower unit seperating at all from the housing? If not, you have another bolt to remove. There is one bolt under the trim tab that is not visible unless you remove the trim tab. Be certain to mark the location of the trim tab relative to the housing for reassembly. Then there is one other bolt I believe in that same area that is to be removed (visible before removing the trim tab). Then the two bolts per side on the underside of the fins. If you are still having problems Monday, I can scan my manual for you and send it. My manual is for 1991-1994 2HP-300HP Evenruide/Johnson motors. So there may be some differences, but probably similarities too.

Good luck!

[jetwrench]

Slayer,


the lower unit will drop down about 1/4 to 1/2 an inch before it hangs up. I can wiggle the shift linkage around so I am sure it is not hung up on that (yet). I know I should take this thing ot the dealer, but I can't let it defeat me!!!!!

[SalmonSlayer]

did you disconnect the shift lever from the linkage arm? There is an arm WAY down under the motor that needs to be disconnected. It is a long shaft that goes up through the lower unit from the gearcase. If you cannot find it, have someone move the shifter/throttle back and forth while you watch the motor to see what moves. Look for the thing most under the motor in the center...usually the hardest to see also. I will bring my book in tomorrow and send ya some info. It will slide right out easily once everything is unhooked properly.

[SalmonSlayer]

did ya get it yet? Do you still need those instructions?

[Jumbo]

My 2000,125 Mer. ,was out 6-13, in the am.and pm,with no problems,6-14, 06:00hrs. going to hit it again, start motor, notice it's not squirting water, shut it down, did it again, no water, kept mtr. in up posistion over night, i didn't lower it down, in past when lowering motor in water, water squirted out the discharge port, it didn't this time, no alarm sounded, shut down again, used soft wire off of 2oz. bottom bouncer, to clear the obstruction out of the line, what was the cause of the obstruction??? any ideas??, oh yes, when it was cleared there was a loud hiss, then followed by some warm,not hot water, which then cooled down to cool water, think we saved my it, then fished for 5 hrs. with no problems, lesson-have check list (mental) of things of operation/safty items, before leaving the dock, hopes this too will save someone some miss fourtune, thanks for the time~~~><>~~Jumbo~~~><>..!!

[SalmonSlayer]

I've heard of weeds collecting and clogging up the lines...but that is in VERY weedy lakes. Just a word of caution: when clearing the obstruction, be extra careful not to jam it in too hard! You could poke a hole in the line! Use some stout weed wacker line that will bend with the bends in the lines. Also, over time the lines will become weak and more susceptible to puncturing if you use a hanger or the sort. Good idea with the bottom bouncer jumbo! I cannot say what the hisss you heard might have been...other than built up water pressure by the pump...this would indicate a pump that is working great with a clogged water line.

[Jumbo]

Thank you for the reply, and the tip, on the plastic line to match the I.D. of the water line, there are made of rubber,which will rot eventually, something too keep a eye out for when the motor cover is off, had the boat out both day of the weekend, not a problem, so the moral of the story, pay attention, or, pay BIG $$ BUCKS, ouch!!:o thank you again, Fish Safe, Boat wise, and catch dem eye's~~><>~~~~><>.. Jumbo..:cool: