Mercury 3.3 pumps little water and other issue

slawosz

slawosz

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Hi,
my Mercury 3.3 telltale water flow is very limited - only drops of water are coming off, it used to be solid stream. It happened recently, as I used it just few time for like 500 yards tender commute. I might hit ground with it - mud, gravel and so on - maybe it got stucked in waterways?

I was flushing it yesterday (in small bucket), and I noticed it spits water through 2 small holes in front, few inches above propeller shaft.
There is not a lot resources on the web, especially no repair manual, but I read some horror stories about resembling gear linkage - in case I would need to change impeller.
If I will lift from the water and there is water coming off the engine - is it sign it works fine?
In worst case, how long I can have engine running before there will be any trouble?

There is second thing that happened yesterday - when starting for flushing I heard loud thud - though it was bucket cracking - turns out it was rubber cover of inspection hole that was blown away - I wonder how come there was pressure to make it happen?

Besides, engine works fine, starts almost immediately, and is stable on low revs.
 
It could just be the telltale that is bunged up. Try poking a thin piece of wire into the hole and see if this cures it - it only takes a few salt crystals to stop the flow. Worth trying before taking more complicated steps!
 
Those rubber gear link covers fly off all the time. I have lost three or four. Last time I bought an aftermarket one on eBay for less than an original Mercury part and it has stayed on ever since. The aftermarket one was a much tighter fit in the hole. I don't know why they come off, but suspect it is some kind of 'backfire' that pressurizes the exhaust.
 
slawosz said:
Hi,
my Mercury 3.3 telltale water flow is very limited - only drops of water are coming off, it used to be solid stream. It happened recently, as I used it just few time for like 500 yards tender commute. I might hit ground with it - mud, gravel and so on - maybe it got stucked in waterways?

I was flushing it yesterday (in small bucket), and I noticed it spits water through 2 small holes in front, few inches above propeller shaft.
There is not a lot resources on the web, especially no repair manual, but I read some horror stories about resembling gear linkage - in case I would need to change impeller.
If I will lift from the water and there is water coming off the engine - is it sign it works fine?
In worst case, how long I can have engine running before there will be any trouble?

There is second thing that happened yesterday - when starting for flushing I heard loud thud - though it was bucket cracking - turns out it was rubber cover of inspection hole that was blown away - I wonder how come there was pressure to make it happen?

Besides, engine works fine, starts almost immediately, and is stable on low revs.
Click to expand...

As suggested check that the telltale itself is not blocked. If it is actually overheating in use then the water passages may be blocked as Vyv suggests or it may need a new water pump impeller.

Here is the Service manual http://www.boatinfo.no/lib/mercury/manuals/22-25-3-33.html#/0

A small bucket is no good for flushing. The water must be deep enough cover the water pump ( on top of the gear case in all engines with a neutral gear position although often " behind" the prop in modern fixed drive engines. Insufficient water depth combined with the turbulence cased by the exhaust gases may be the cause of your lack of water flow.

Cannot explain the sudden expulsion of the rubber plug . A back fire of unburnt fuel and air in the exhaust perhaps ????
 
Last edited:
Thanks for answers. This forum is excellent!
I am thinking about using guitar string, will give a try.

VicS said:
A small bucket is no good for flushing. The water must be deep enough cover the water pump ( on top of the gear case in all engines with a neutral gear position although often " behind" the prop in modern fixed drive engines. Insufficient water depth combined with the turbulence cased by the exhaust gases may be the cause of your lack of water flow.
Click to expand...

Water is deep enough to cover all holes and engine is tilted so all holes are submerged. The think is its small boat and I need to carry entire water on my tender, so the smaller bucket the better. I was thinking about making something for close fit, but haven't manage find time...
 
slawosz said:
Thanks for answers. This forum is excellent!
I am thinking about using guitar string, will give a try.



Water is deep enough to cover all holes and engine is tilted so all holes are submerged. The think is its small boat and I need to carry entire water on my tender, so the smaller bucket the better. I was thinking about making something for close fit, but haven't manage find time...
Click to expand...

The water pump should be submerged. This means that the water should be deep enough to be well above the gearcase to driveshaft housing, (( by a couple of inches is the usual recommendation ) This is unlikely to be the case with a "small bucket"....
 
VicS said:
Hve you seen the link to the service manual which I added to #5?
Click to expand...
Yes. It is great!

VicS said:
The water pump should be submerged. This means that the water should be deep enough to be well above the gearcase to driveshaft housing, (( by a couple of inches is the usual recommendation ) This is unlikely to be the case with a "small bucket"....
Click to expand...
Well, relatively small - the one that is used with mop, holds around 2 gallons of water.
 
I had a similar issue with my mariner 3.3HP, the telltale pipe was just dripping. I used a piece of galvanised garden wire I had (from b&q), which was perfect size. To clean I removed the pipe and cleaned then the connector, it looked like salt deposits on the wire. After that it was a steady stream of water.

Also I used a plastic large waste bin which was a perfect height to clamp the drive onto using a piece of wood as a support.
 
Just adding to the previous replies: It is not the amount of water coming from the telltale that is important. It is not the main passage for cooling water and the cooling may work properly even if this hole is totally blocked. The real indication of the condition of the pump and the main water passages is the water temperature. Check it while the motor is on full power. If it is cool enough to tolerate it by a bare hand, you have nothing to worry about. Just try to clear the passage when convenient. If the temperature is close to boiling point, your cooling system needs service urgently otherwise a damage to the motor may result.
 
Thank you!

jiris said:
Just adding to the previous replies: It is not the amount of water coming from the telltale that is important. It is not the main passage for cooling water and the cooling may work properly even if this hole is totally blocked. The real indication of the condition of the pump and the main water passages is the water temperature. Check it while the motor is on full power. If it is cool enough to tolerate it by a bare hand, you have nothing to worry about. Just try to clear the passage when convenient. If the temperature is close to boiling point, your cooling system needs service urgently otherwise a damage to the motor may result.
Click to expand...

Thanks, will check this.

vyv_cox said:
Not an option for many people. Carrying a container that rolls up for stowage is very convenient, allowing the outboard to be flushed quickly and easily.
Click to expand...

Unfortunately, its my case. Ideally, I want to do everything on board. I live in flat and my shed is balcony and car trunk. It does not make my wife happy ;) I am going to try dry bag as water container, its cheaper than fender. Although I am still looking for better solution, maybe over winter I will do custom made with GRP.
 
slawosz said:
Unfortunately, its my case. Ideally, I want to do everything on board. I live in flat and my shed is balcony and car trunk. It does not make my wife happy ;) I am going to try dry bag as water container, its cheaper than fender. Although I am still looking for better solution, maybe over winter I will do custom made with GRP.
Click to expand...

Keep checking the boatyard skips, burst or leaking fenders are often to be found. I flushed my outboard with my cut off fender this morning, very quick and easy.
 
I tried wire in my Mercury 2.2 but no luck. What worked was a small drill bit rotated by hand. Took quite a while.
 
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