Tell-tale :]

Tim M · 06 May 2004, 19:29

Our club rescue boat tell-tale got blocked up the other day, so I unblocked it. We have a new guy who has just started driving the rescue boat, and whilst I was unblocking it he commented that it didn't really matter if water stopped coming out of the hole, as it was just an indication that water was going through the system, and that rest (majority) of the cooling water came out somewhere else (like the exhast).
I was under the impression that all the cooling water came out of the hole.....
Please confirm (or otherwise) my theory.

Louise · 06 May 2004, 19:34

Quote:

Originally Posted by timofengland

I was under the impression that all the cooling water came out of the hole.....
Please confirm (or otherwise) my theory.

I don't think ALL the cooling water exits via the tell tale - I think this is just an indicator that the water is circulating around the system correctly. Many marine engines eject cooling water into the exhaust system at some point. As far as I know outboards do this.

ashbypower · 06 May 2004, 19:40

Tim OE The tell tale is just that, an indication that the water pump is working. Most of the cooling water exits via the exhaust. However its good practice to keep the tell tale clear, if the pump packed up this would be the first indication.

Brian

Tim M · 06 May 2004, 19:45

I C. So really, when water stops coming out it's not the end of the world; I have always had visions of my engine blowing up after a few minutes!

swginn · 06 May 2004, 19:48

Quote:

he commented that it didn't really matter if water stopped coming out of the hole, as it was just an indication that water was going through the system, and that rest (majority) of the cooling water came out somewhere else (like the exhast).

The only problem with this theory is how do you know that the tell tail is blocked and not that the cooling system has failed or the intake is blocked, causing serious damage.

I always carry a narrow piece of wire onboard to unblock the tell tail, in case it ever happens.

Daniel · 06 May 2004, 19:49

Something else i learnt last year is that some (Smaller mariners - a 6hp in my case) have a thermostatic tell-tail. What this means is that it is not always working, infact it does not come out for some time (when the engine is warm) and even when in use if the engine is running too cool it will stop for a bit! What a stupid idea... but i did feel silly taking it to the repair shop only to be told this!!!

timboli · 06 May 2004, 19:58

Maybe that is something to do with why on an old evinrude 15 I have(doesnt get used much),water exits the back upto half throttle but stops after this,I did take it to an evinrude dealer with this as a problem when I first got it but didnt really get a clear answer as to why this happens except that they thought it was working OK.
It has never overheated yet but I have never used it at high engine speed for more then 5 minutes.

Hightower · 06 May 2004, 20:07

Daniel, obviously the tell-tale is after the thermostatic control valve. What a stupid design. Should have been before it and the water comming out would have kept the water moving through the Impeller.

Paul F · 06 May 2004, 21:52

Daniel is right some of the merc/mar. do have the tale tale coming off of the thermostat housing and when it opens it allows greater flow through the tale tale,dumping some of the hot water.Not the best of designs. Still on the bigger lumps at least you have the warning horn to alert you or smartcraft etc of overheat.

Bajan · 07 May 2004, 13:14

Tim!
I would definitely put a lot of importance on the tell-tale! It is your one surefire way of knowing if your engine is overheating and about to give up the ghost. It could be the difference between you rectifying a relatively simple issue like a piece of grit in the passage and having to replace your engine that's just overheated to the point of no return.

tim griffin · 07 May 2004, 14:55

TIM
CARRY AROUND A METRE OF STRIMMER WIRE (PLASTIC) to unblock the tell tale .regards tim
www.griffmarineservices.co.uk

Mark Halliday · 07 May 2004, 15:45

Quote:

Originally Posted by tim griffin

TIM
CARRY AROUND A METRE OF STRIMMER WIRE (PLASTIC) to unblock the tell tale .regards tim
www.griffmarineservices.co.uk

Sometimes the simplest things...........
I'm off to the shed now.

aligator · 07 May 2004, 23:06

Hi Tim
I always thought the the telltale was just that, an indication of a problem if it stopped running. after all when first starting the engine you look for the spurt of water.
ask your new driver how long he was prepared to run the engine with no water coming out, if you consider it the same as the oil light on a car you cant go far wrong. Just how far down the road do you go with the light on.
Alistair