2001 Merc 50 was overheating # idle, new water pump now worse

[Trader Vick]

My Merc is new to me (2 months) a 2001 Mercury 50 hp 4-stroke, non-efi (has carburetors), 4 cyl serial 0T229967, SMALL Foot gear ratip is 1.83:1 (so Not a big foot) , , had been mostly fine, except recently at idle and very low speed, alarm horn under dash started coming on once on while so would shut down immediately and let cool down, start up and all OK. tell tale was peeing at all times. No temp gauge in dash. Stated happening more often, bought water pump kit,46-812966A11 replaced impeller, (old impeller vanes stiff stayed bent after removal, and had dry rubber stress cracks but no pieces missing. replaced impeller top housing and water tube seal on top of pump (while apart flushed with hose from bottom water intakes up and from pump inlet down, lots of flow. re-installed lower unit and tested. Now not peeing at all low rpm, does pee some at higher rpm, horn alarm comes on every time now, in 2-3 min. have to shut off. Removed unit again checked , inverted impeller changed direction of splines and re-installed, same exact result. new parts seem a good fit impeller snug. Need suggestions what may be cause, what to check, what to try etc.
Signed
Baffled in Bonita.

 

[MH Hawker]

Re: 2001 Merc 50 was overheating # idle, new water pump now worse

thermostat or salt build up has clogged the cooling system.

 

[CharlieB]

Re: 2001 Merc 50 was overheating # idle, new water pump now worse

thermostat or salt build up has clogged the cooling system.

Exactly!

Once exit passages begin to restrict exit flow, cooling reduces.

You need to either disassemble the exhaust side and begin manually cleaning out water passages or get the motor into a barrell where you can start running a high mixture of de-salting chemical.

Personally, I would order the exhaust gaskets.

 

[Trader Vick]

Re: 2001 Merc 50 was overheating # idle, new water pump now worse

Exactly!

Once exit passages begin to restrict exit flow, cooling reduces.

You need to either disassemble the exhaust side and begin manually cleaning out water passages or get the motor into a barrell where you can start running a high mixture of de-salting chemical.

Personally, I would order the exhaust gaskets.

Ok replaced thermostat, Mild green corrosion, no salt corrosion,(was a fresh water boat use for last 12 years, only been in salt water a few times since it was just brought down form Wisconsin). anyone have a link to the manual pages to do that job? I have jet to get the manual. (BTW which publisher makes the best manual /)

 

[carholme]

Re: 2001 Merc 50 was overheating # idle, new water pump now worse

Your s/n comes up as:

MERCURY - ( 50 H.P. (2001 ))
Serial No: 0T229967 Model No: 1F51412YD

Parts List for model 1F51412YD:

40/50/60 (4 CYL.) CARB(4-STROKE) - Mercury, Mercruiser, Force, etc. Parts Lookup

The manual you require is P/N: 90-858896

See my PM to you in Notifications at the top of the page.

Gerry

 

[MH Hawker]

Re: 2001 Merc 50 was overheating # idle, new water pump now worse

Then I would give it a test run at this point before going deeper into, a bad thermostat will cause all sorts of heating problems.

 

[Jeep Man]

Re: 2001 Merc 50 was overheating # idle, new water pump now worse

Hey TV. PM sent

 

[Trader Vick]

Re: 2001 Merc 50 was overheating @ idle, new water pump now worse

Re: 2001 Merc 50 was overheating @ idle, new water pump now worse


OK, replaced thermostat, and while thermostat was out, put lower unit back on, and started boat in the water.
RESULT:at idle no water flow out pee hole, no water flow out thermostat opening either, increase RPM gradually, did not start seeing water out of thermostat opening until 1800 rpm, same with pee hole.

Seemed like water not getting up to engine very well.

So, removed lower unit AGAin,and removed thermostat, hooked hose to pee hole threaded-socket and flushed, also ran water up water tube until it came out of thermostat hole and pee hole. Put lower unit back on, same RESULT.

Note: I did buy the whole assembly, kit,(46-812966A11) plate housing and all. the only thing I could not do was to replace the bottom plate, (it is in very smooth condition) and that is because I can't figure out how to get the shift shaft connector off. It seems to need to come off to lift off the plate. Any suggestions?

 

[tazrig]

Re: 2001 Merc 50 was overheating # idle, new water pump now worse

Vick, Here is a link to an OEM PDF manual for your bigfoot:

Boatinfo - Mercury Service Manual for 40-45-50-bigfoot

 

[Trader Vick]

Re: 2001 Merc 50 was overheating # idle, new water pump now worse

Thanks Taz, how can I be sure mine is a big foot? It does not have side anodes, but I heard they came out later, the cavitation plate seems kinda big,so I think so, but here are some pictures.

 

[carholme]

Re: 2001 Merc 50 was overheating # idle, new water pump now worse

Do you have a gear ratio sticker on the lower unit. Non Bigfoot is 1.83:1, Bigfoot is 2.31:1, the non bigfoot has a torpedo diameter of 3.44" while the bigfoot is 4.25".

You will see this in the service manual, Sec 6A/B.

Gerry

 

[tazrig]

Re: 2001 Merc 50 was overheating # idle, new water pump now worse

+1^^^ Vick I was going by your own identification in your first post.

 

[Trader Vick]

Re: 2001 Merc 50 was overheating # idle, new water pump now worse

I don't see any stickers of any kind on the lower unit, but torpedo diameter measures just under 3 1/2, so the 3.44" must be it, with a gear ratio of 1.83:1.
The Complete pump kit I was sold by my local auth. auth merc shop, is Quicksilver # 46-812966A11. Now I am going to go back and try and find if that is the right one !

 

[carholme]

Re: 2001 Merc 50 was overheating # idle, new water pump now worse

Should be OK with that. See the parts list under GEAR HOUSING (DRIVE SHAFT)(1.83:1 GEAR RATIO), last item on the page.

Gerry

 

[Trader Vick]

Re: 2001 Merc 50 was overheating # idle, new water pump now worse

Sorry Taz, My Bad, I just didn't know. My parts counter guy looked at my phone pics and said he thought he cavitation plate looked big, so he thought may be a big foot, but it's not.

 

[Fed]

Re: 2001 Merc 50 was overheating # idle, new water pump now worse

Is the key for the impeller in place?

 

[Trader Vick]

Re: 2001 Merc 50 was overheating # idle, new water pump now worse

OH YES, most definitely. Just installed the whole kit, from lower seal to upper housing, followed merc manual to the letter too. Getting ready to put in on in shortly, and see what happens. will check water feed pipe for blockages 1st, will then test run, if not peeing or cooling, will check water pressure at power head, if good, will start looking at exhaust leaking in to water path entering engine.

 

[Trader Vick]

Re: 2001 Merc 50 was overheating # idle, new water pump now worse

still trouble, same as it was, engine not getting enough water,wondering if new upper pump seal that was in the kit, 2 quick pics below and a link with more detail pics too...

https://www.dropbox.com/s/8h1s5lzs5fg19ti/water%20pump%20seal%2C%20and%20water%20tube.zip

(white tube with black insert, about 2") is not right somehow...

Well I did replace all. The big, sorta cone shaped lower seal set,, (pry out with screwdriver),base plate and all the gaskets, impeller, key, top housing, top seal, and every gasket and washer. Followed the merc manual to the letter too, including turning drive shaft clockwise, forward,while lowered top pump housing so vanes are in correct forward way. T-Stat brand new too. Re- install and test on boat, in water, still trouble. Removed side cowlings on engine and checked feed tube visually and for any issues. From side of engine, I could see water pushing out from what appeared to be just below the bend in feed tube, as if top pump seal was not in place, or too short, or 'something" Removed Lower Unit, slipped cut garden hose on to feed tube, and water flowed very well. Reduced hose pressure, a lot, to be more like the water pump,started engine, warmed up fine, peeing well, and temp was good, ran fine,for 10 min. no evidence of exhaust pushing down water tube. how long is thata seal tube supposed to be on top of the pump, maybe mines wrong? Too short?

 

[CharlieB]

Re: 2001 Merc 50 was overheating # idle, new water pump now worse

Do you still have the original pump?

Look inside the upper tube, there should have been a rubber 'seal' that the water transfer tube sealed against as the gearcase was raised into position.

I suspect your new pump is not sealing against the water transfer tube, allowing water to spill and not pumping up into the motor.

 

[Trader Vick]

Re: 2001 Merc 50 was overheating # idle, new water pump now worse

You nailed it.
I have the original pump, bot NOT the original Coupler Tube seal,(fell off the dock during removal,in to the silt, I used SCUBA to try and find it (Sunday, stores closed),

I am sure now, it was longer.The kit should have had both lengths of coupler tube seals, but kit was old stock on dealer parts shelf, (plastic bag unsealed when I got it, I suspect the longer had been robbed from the kit for a repair), only shorter one in there, but, I did not know, nor discover until Saturday, the possibility a 2nd one. Turns out The one I need is 859770-1 WATER TUBE SEAL, GLM Part Number: 85182; Mercury Part Number: 859770-1. It is longer.Amazon.com: WATER TUBE SEAL, 4-Stroke | GLM Part Number: 85182; Mercury Part Number: 859770-1: Automotive

If anyone knows of a Florida dealer who can send out today for one day delivery, (so I can go out on Christmas) please post !! (Meanwhile I am going out to Naples, this AM, to try and find one local .