Tell Tale woes from down under !!

hundee r1 · Jan 26, 2016

Hi again guys. Been at least 18 months since my last query and Im happy to report my Force has been going great here down under, probably done 30-40 odd hrs on it since my rebuild with the help of this forum.

During routine maintenance I changed out the impella about a month ago. It had been working fine up until then, after re assembly it seemed to pump water no worries. Turned the motor off and a couple days latter, prior to going out for a fish, fired it up and all off a sudden my tell tale didnt show anything!!
Quickly turned the motor off, disassembled the pump housing, where I found nothing strange. Re assembled, fired back up, tell tale showed a stream again...
Went fishing, tell tale showed a stream all day.
1 month later, start boat, tell tale working, go fishing, tell tale worked all day until nearing my return and noticed its barely a trickle.

The 2 holes in the mid leg still show plenty of water and I havent over heated the motor, but for the life of me I cant figure out why all off a sudden Im having an intermittent tell tale stream!!

The tell tale comes from the plug at the top of the cylinder head, the impella was swapped out using OEM quicksilver.
I didnt do any of the gaskets or housings, Im wondering what to look for when I pull it all down again!!

Its a 1992 90hp, has the stainless steel sleave inside the plastic housing, only thing Im double taking is that someone at some stage over tightened the plastic water pump housing and it has a slight crack around one of the bolt holes. Its not thru the plastic into the inside, plus it has the stainless steel insert right? Not to mention, its always been like this, but the tell tale has only just started playing up, maybe the crack has got worse.

Ill post pix upon disassembly

GA_Boater · Jan 26, 2016

Was the impeller missing any pieces or chunks when you changed it a month ago?

hundee r1 · Jan 26, 2016

Nope
was just routine maintenance

GA_Boater · Jan 26, 2016

The tell tale hose like to be a bug house some times. Run a piece of wire through the hose. If there is a blockage, that may dislodge it.

Otherwise - tear down pics of the impeller housing.

hundee r1 · Jan 26, 2016

Yeh, I blew back thru the tell tale hose once on dry land and it made minimal difference when re checked on muff's. Disassembly is in order me thinks

hundee r1 · Jan 26, 2016

Can I also ask, Frank posted a great thread a few years back in relation to the water outlets on our Force motors and what they all mean in relation to the flow thru the motor.
Anybody have a quick link for it? May help me understand the issue a bit more.

tommarvin · Jan 26, 2016

I would push a large wire or weed eater line all the way through the tell tale hose.You can't blow hard enough. If this doesn't fix it.
I think you have a blockage in the water tube, remove lower unit rum a large wire up water tube to clear it out. Or it's still in the water pump housing.

Are you sure you have the correct impeller. Free factory service manuals at www boatinfo.no/lib/library.html. Force and Chrysler are in the OTHER tab at bottom Find your motor, find the water pump

There is some kind of blockage that's random, when whatever is in there gets in the right position. It's just a guess. Tell us what it was, when you find it..

hundee r1 · Jan 26, 2016

I took my old one to the boat place and they matched it. The Water pump kit I'm looking at buying is this:

http://www.ebay.com/itm/NIB-Force-8...ash=item463f0e3b37:g:qzwAAOSwstxVEFcP&vxp=mtr

But with the Aussie $$$ being so poor, its an expensive guess.

First thing I will do is run the motor at home with the tell tall hose disconnected.
Next step will be to take the leg off and run a hose up the intake and see what happens.
All else failing, disassembly of the pump and post pix on here before purchasing a new kit.

As for updating the forum, with every thread I've had on here, I've always closed it out with the outcome, will be no different this time!!

jerryjerry05 · Jan 27, 2016

IF??? your impeller worked it's probably not the wrong one.
Most of the exhaust and water exits through the snout.
The 2 holes on the back are for the pressure release system.
You can have very little to no water or a bunch of water coming through the holes.
Depending on how clogged the system is.
Try back flushing with a hose.
I've never seen the Force impeller used in another application. It was used from 89-94
Test the overheat system.

Frank Acampora · Jan 27, 2016

Assuming you have a pisser fitting at the top of the head, remove the hose and then remove the pisser fitting. Clean out the fitting. Remember: If you have the fitting screwed into the back of the thermostat housing until the thermostat opens you will get very little to no water out of the pisser.

Water flow is from the water pump up to the center of the match plate. From there it makes a 90 degree turn and travels to the edge of the match plate where there is a square 1/2 inch pipe plug. As an aside, I have heard that that plug can be removed. I have never been able to remove it.

Next the water travels up through the match plate and up the front of the exhaust water jacket. At the top it is diverted down over the stainless plate. Somehow it also gets to the rear exhaust water jacket--I forget how. After passing through the exhaust jacket It passes from the jacket into the cylinder jacket where it is diverted around all cylinders and then up to the thermostat.

The thermostat has a small notch in the frame to pass a small amount of water. This notch should be oriented up. This notch ensures that at all times a small amount of water is passing through the exhaust and cylinder jackets. This prevents overheating during normal operation with the thermostat closed. It will not be enough water to prevent overheating if the thermostat malfunctions. This water also ensures that (again) under normal operating conditions the stainless plate is not overheated and burned through by exhaust gases.

Once the thermostat opens, cooling water is passed down the head and again enters the match plate. Most water is dumped into the space between the exhaust downtube and midleg casting. This keeps the exhaust downtube cool. There is a groove on the underside of the match plate which travels around to the side of the exhaust downtube. This groove also carries water for the same reason. If you seal the match plate to the midleg casting with silicone do it sparingly so as to not block this groove. Old Chrysler engines actually used a gasket here but by the 1970s this was discontinued.

The exhaust downtube has a flange near the bottom that seals against a flange in the midleg casting with a soft gasket. There are usually several holes in the midleg flange but some may be plugged and some may have white plastic tubes held in them (depending upon engine year and design.) These meter the water lost to the exhaust. Meanwhile, during normal; operation water builds up around the exhaust downtube and fills the midleg, exiting through the two exhaust relief holes in the back of the engine. Because of the drain holes and low water flow, on MOST Force and Chrysler engines it takes a while on muffs for water to exit the idle relief holes. As long as water is exiting the exhaust in decent quantity at the beginning of operations on muffs, the engine is getting cooling water. Remember though that most garden hoses and muffs can not deliver the volume of water that the pump is designed to deliver at high RPM-- Another reason to not run high RPM on muffs.

Thus: Exhaust relief holes have two functions 1. Release of back pressure when the engine is idling and sitting low in the water, allowing a more reliable idle.
2. Maintaining a full water volume around the exhaust downtube, keeping both it and the midleg casting cool.

Personally I don't believe in adding a pisser to Force engines. None of my engines have one with only one exception and none run worse for it. I did run my 150 into a sandbar and clogged up the water tube and possibly some of the water passages. The tube was so packed that I needed to run an extra long drill bit up it to open it.To visually show that I had cleaned the blockage from water passages, I did add a pisser. However, I never look at it anymore.

Jiggz · Jan 27, 2016

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This is cooling water flow for a 4 cylinder. See if this helps. Note the t-stat having two water flow paths as described by Frank.

Frank Acampora · Jan 27, 2016

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Several photos showing the match plate downtube and midleg. DANG--Double post with one extra photo on this one. Mods: How can I delete #12?

tommarvin · Jan 27, 2016

All I can add after that thesis , you can buy the rubber impeller only. We have a Force 125 and our impeller cost 13 bucks,at iboats.com

Remove lower unit, remove t-stat, pour water in t-stat opening does it drain out water tube fast?

GA_Boater · Jan 27, 2016

Got rid of post #12, Frank.

hundee r1 · Jan 27, 2016

Thanx a heap guys, without this forum Id be much poorer and even more frustrated.

Thanks Frank for re explaining the water circulation, the 2 holes have a nice waterfall of water at idle , both in the water and on muffs, at cruise, it turns into a spray.
Again, I don?t think the motor is missing out on cool water nor has it over heated, I just suspect the efficiency is down just enough to render the tell tale useless and I like the visual check of having it working.
Jerry, I tested the overheat buzzer when I rebuilt the motor, it worked and I haven?t heard it since, will check again just to be sure. Just pull it out of the head and put a lighter near it if I recall?

I will pull the lower leg tonite, take fitting out of the thermo housing for the tell tale and put a hose up the water pipe to the motor both with and without the thermostat fitted.
I vaguely recall when I rebuilt the motor double taking the thermostat install, but its worked perfectly for 30 odd hrs , its only since replacing the impella under routine maintenance that I?ve found it?s become intermittent.
I didn?t disturb any of the gaskets in the lower housing when swapping out the impella and the stainless steel plate and housing looked fine. Like I said, its only the crack in the plastic housing that has be concerned, and why I?m contemplating getting a complete kit.
But having a close look at how it works, the plastic housing is just there to hold down the stainless steel one and somewhere for the water pipe to slide into.
Even then , it has a relief hole of sorts in the top of it?
Lastly, I will post pix tonite when I pull it apart again, but the small square section seal, that goes outside the plastic water pump housing doesn?t it? Under the drive shaft to cushion the shaft hitting the housing if something was too long?

Frank Acampora · Jan 27, 2016

The diagrams and manuals I have don't show the exact placement of the square "hose washer" seal. If you look closely you will see a gap between the plastic housing and the stainless cup just the size of that seal. However, I have never seen one there. They always seem to be above the water pump. I can't see where it does any good because there are two water relief slots in the top of the plastic housing. The shaft joining collar is located on the splines by an internal circlip so it can not work down to touch the pump. In fact, because of the spline length it simply won't work down. So: What does this seal do? IDK! Maybe it is a slinger meant to throw water and dirt away from the shaft. I replace them where I find them, around the drive shaft and above the water pump. I would certainly appreciate finding a factory stock lower unit so I could see the correct placement.

I just had a thought--and thinking gets me into trouble LOL. That drive shaft and gear arrangement has the thrust upwards and that is why there is the threaded ring to hold the bearing down in the casting. During running the taper of the gear teeth forces the pinion upwards into correct gear lash clearance. There is nothing to keep the drive shaft from dropping with the engine stopped and allowing the pinion to rest with zero lash. The impeller is slip fit on the shaft and the Mercury drive pin is vertical in a slot. The washer may be there to hold the shaft up when the engine is not running thereby prolonging gear life.

hundee r1 · Jan 27, 2016

Yes, you speak a lot of sense Frank as per usual. I too noticed that circlip inside the joiner and figured no clash would ever occur between it and the pump housing. Bizarre!!

hundee r1 · Jan 28, 2016

Ok, so its late night here atm, so Ill try and be brief but upload lots of pix and vids.
Started it on the muffs and took quick vids, one at idle, and one at fast idle , 2000rpm plenty of water coming out from the 2 holes and the snout? and the tell tale aswell.
Last time I had it running it was barely a trickle from the tell tale. That was at the ramp during wash down,on the muffs and after a 15min blast back from my fishing spot (bare with me).

Firstly, pulled the tell tale off and as suspected its not blocked.
Next the thermostat housing came off, revealing nothing jammed or blocked and other than some slight corrosion aiding passage of water pre-thermo opening, it all looks fine to me. Thermo stat opened instantly in a boiling cup of water.
I then pulled the over heat sensor out of the head and started heating it with a lighter. With the ignition on, I then put it back in the head and the alarm sounded at my controls for a while till it cooled down.
I then dropped the lower leg and inspected the water intake, then put a running hose into it.
Water started coming out from the leg weep holes, then from the missing thermostat housing. When I blocked the opening with my hand, a 6" gyser shot up from the tell tale fitting. Couldn't tell how much would've come from the snout, as the hose wasn't a proper seal on the intake tube.
So next I dis-assembled the water pump.
Again, impella looks brand new,(it is) stainless steel housing and plate look fine and the gaskets are intact but still attached to eitehr side of the stainless steel plate.

I had a good look at the pre-mentioned hairline cracks in the housing, I still consider the one around the bolt hole non significant since its the stainless steel housing that the impella runs in.
But, what I did notice this time around is a hairline crack running vertically in the part of the housing that the water intake tube sits in!!
Its barely noticeable in real life, but is all the way thru, its the mark on the right in the pic, the mark on the left is just a scrub mark. Its tiny and I cant see daylight thru it, but I think this is causing some inefficiency in the system.
Enough for when the motor is up to temp, with a wide open thermo stat, the point highest in the system is left with marginal flow, the tell tale!!
Could explain why when I first launch or start the boat after sitting idle for a while, the tell tale flows, once warm, it trickles....

So, my plan, is to price a new housing locally, I'm hoping its shared on Mercs, will make it more affordable, else my dealer has quoted me $160AU for the whole kit.
I was considering having a go at repairing the cracks carefully from the out side of the housing with some high quality epoxy. Maybe just go for a run along the coast instead of open ocean and see if it fixes it before ordering a new housing....

I will upload links to my host site once they upload...

jerryjerry05 · Jan 28, 2016

The 125 takes a different impeller than the 92/90.
The 125/85 pump housing was pot metal the 92 housing had a stainless insert and a different impeller.

Top of the pump housing, is the seal there?
Small hairline cracks shouldn't be a problem.
Worried? fil them with silicone.

The housing was used from 89-94 then they used Mercury(sorry)

To find out what your part will work on: boatsdotnet Parts diagrams
Go to the Mercury tab and the second set of motors.
Open the Force one.
Then find the year and then any 90hp will work(unless you have the serial#)
Find the part and open that up.
Scroll down and it shows what years and applications that part fits.

hundee r1 · Jan 28, 2016

Tell Tale woes from down under !!

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