Gettin Warm

[fidel]

I got a 12ft tinny with a 25hp johnson (circa 1992)

Took it out towing some mates on a knewwboard on weekend - a fair bit of load (well a lot of load) for a good couple of hours.

Afterwards I noticed that it was pumping out hot water on idle, but once i gave it some throttle it was luke warm water.

I was under the impression that when an impeller dies - it pumps out hotter water the harder the engine is working?

Any ideas anyone?

[hairyweasel]

Are you getting a good volume of water or a poor flow?

[noname]

johnno's and evinrudes do have a tennancy to run hot, well hotter than some other makes,merc's run very warm then cool, due to the thermostat opening and closing, even the tell tale will slow right down at times, yammies run cool all the time. if you've got a good stream of water comming out from the tell tail, thats a good thing, as i think you are aware of, but if your concerned, check the thermostat. but don't cut the guts out of it and put it back together, replace it, as it will cause damage to the rings if it runs to cold. but in saying this, checked a mates boat which was pumping some water out the tt but not much and was running hot, the impeller was placed in the wrong way after being checked from what i can gather. i'm not a prick all the time. good luck with it.

rob

[wesfish]

fidel wrote:

I got a 12ft tinny with a 25hp johnson (circa 1992)

Took it out towing some mates on a knewwboard on weekend - a fair bit of load (well a lot of load) for a good couple of hours.

Afterwards I noticed that it was pumping out hot water on idle, but once i gave it some throttle it was luke warm water.

I was under the impression that when an impeller dies - it pumps out hotter water the harder the engine is working?

Any ideas anyone?

when the impellar goes it stops pumping water , i say it was due to the load pressure from towing behind it , or you did not have the right oil mixture which causes friction and make it run hotter.my 25 yammy runs alot warmer when towing the tube with the kids on it , its just under load!!! if there is water pumping out nicely then dont worry to much \..

[bootyinblue]

Yea the strength of the water flow is more indicative of whether the impeller is on the way out. Sure it will run a bit hotter if there is not enough water circulating, so it would depends on how well its piddling!

[fidel]

Its pumpin out a crap load of water!!!!

I think I realised the problem - apparently my brother didn't add any oil when we put 10L in at the servo! IDIOT!!!

[werewolf]

fidel wrote:

Its pumpin out a crap load of water!!!!

I think I realised the problem - apparently my brother didn't add any oil when we put 10L in at the servo! IDIOT!!!

That certainly wouldn't help as per what Wes said...

Not that I know much about outboards (okay, I don't know anything), but as far as the water being "cooler" at high RPM, wouldn't there be a great water flow at higher RPM, and due to to greater flow rate, the water coming back out would actually be a bit cooler as there is less time to transfer the heat from the engine?

[bootyinblue]

fidel wrote:

Its pumpin out a crap load of water!!!!

I think I realised the problem - apparently my brother didn't add any oil when we put 10L in at the servo! IDIOT!!!

Ohhh dear..... time to put a bit extra oil in the next tank and run it at slow to medium revs for quite a while, but vary the revs all the time. Dont just sit on 1/4 throttle.

I ALWAYS put oil oil in stuff before the petrol. No oil to put in, then no petrol goes in!