Optimax norm temp

Tony Barber · 26 April 2005, 20:14

Hi,

Does anyone know the normal temp an optimax 150 should operate at idle and WOT?

I thought 2 new thermostats had cured my overheat at idle, however its back again!

Also, any tips for changing the impeller? Is it DIYable? I found a good thread on changing the impeller on a Yam. Any major differences?

Thanks,

Tony.

Tony Barber · 27 April 2005, 12:18

Hello

Searider · 27 April 2005, 13:09

Hi Tony,

Not sure of the correct running temperature but it must be in the owners manual somewhere - mine isn't to hand though. If you don't have one they can be downloaded from.

Changing the impeller looks simple but I always leave it to my dealer.

Not quite the answeres you were looking for perhaps - but at least a reply

Regards

brucehawsker · 27 April 2005, 14:41

I have had overheat warnings when crawling (2 knots - reading a manual or testing the radio) on the way down the Lymington River a couple of times - 70C ish. A quick shut down and a restart two mins later on one occasion, and a few more revs to get the water flowing on the other occasion, solved it...

Tony Barber · 27 April 2005, 14:52

Quote:

Originally Posted by Searider

Hi Tony,

Not sure of the correct running temperature but it must be in the owners manual somewhere - mine isn't to hand though. If you don't have one they can be downloaded from.

Changing the impeller looks simple but I always leave it to my dealer.

Not quite the answeres you were looking for perhaps - but at least a reply

Regards

Cheers Duncan.

I can't find the normal temp in the manual. I may get the dealer to change the impeller and just watch/help so that I can do it next time.

Tony.

Tony Barber · 27 April 2005, 14:53

Quote:

Originally Posted by brucehawsker

I have had overheat warnings when crawling (2 knots - reading a manual or testing the radio) on the way down the Lymington River a couple of times - 70C ish. A quick shut down and a restart two mins later on one occasion, and a few more revs to get the water flowing on the other occasion, solved it...

Hi Bruce,

My temp guage was showing 100c at WOT and climbing up to 170c at tickover. It seems to run OK at WOT still? The impeller is on order so hopefully that is it.

Thanks

Tony.

Searider · 27 April 2005, 15:30

Tony,

170C! - surely you mean 170F?

Duncan

Quote:

Originally Posted by Tony Barber

Hi Bruce,

My temp guage was showing 100c at WOT and climbing up to 170c at tickover. It seems to run OK at WOT still? The impeller is on order so hopefully that is it.

Thanks

Tony.

Paul F · 27 April 2005, 17:20

Tony
What is the block water pressure at idle ??
If you have lack of water flow do to worn impeller it would normally alarm under block pressure.
So it well may not be the impeller?
I know that doesnt help but if you have good block pressure at idle then the impeller sound as though it may be ok.
To change it is quite easy.PM me if you decide to change it
Paul

Tony Barber · 28 April 2005, 08:14

Quote:

Originally Posted by Paul F

Tony
What is the block water pressure at idle ??
If you have lack of water flow do to worn impeller it would normally alarm under block pressure.
So it well may not be the impeller?
I know that doesnt help but if you have good block pressure at idle then the impeller sound as though it may be ok.
To change it is quite easy.PM me if you decide to change it
Paul

Hi Paul,

I think the block presure was around 1.1 at idle. That is from memory. Unfortunatley my alarm buzzer is knackered so unsure if it alarmed. I tend to rely on the guardian system, which did not kick in.

I find the problem with smartguages is that they alarm all of the bloody time!

Thanks for the offer of help.

Tony.

tim griffin · 28 April 2005, 08:18

Do you get an alarm up saying check Pitot

Tony Barber · 28 April 2005, 08:28

Quote:

Originally Posted by tim griffin

Do you get an alarm up saying check Pitot

No.

swginn · 28 April 2005, 10:06

Quote:

Originally Posted by tim griffin

Do you get an alarm up saying check Pitot

Surely that would be nothing to do with engine cooling. The Pitot is an engine speed sensor.

Figures of 170C are worrying and I would question their accuracy. Surely at 170C you would be doing a lot of damage to the engine and the engine guardian would kick in. I would think it might be a Smartcraft problem or a temp sensor problem.

My Opti can run hot at idle when running for long periods or when motoring very slowly. She's never run hotter than 70C though, and with a quick blip of the throttle this drops dramatically. I would also check that your cooling passages are clear as salt deposits can build up and restrict cooling of the block.

TIM · 28 April 2005, 14:17

Quote:

Originally Posted by tim griffin

Do you get an alarm up saying check Pitot

which menu or Guage is the contol to turn off the pitot tube , as our set up runs on a paddle wheel?????

swginn · 28 April 2005, 15:50

Quote:

Originally Posted by TIM

which menu or Guage is the contol to turn off the pitot tube , as our set up runs on a paddle wheel?????

You need the Cal2 screen;

Hold Mode and Troll+ for 10 seconds on the Tacho to access the screen. The second menu will be for the Pitot, select No to turn it off.

Just to let you know that using the paddle wheel only will result in inaccurate figures at high speed. The Pitot is more accurate at high speed.

Our setup uses both the paddle & pitot and is very accurate (compared with GPS). I think we've got the transition speed between paddle and pitot sensors set to around 15 kts.

HTH!!

tim griffin · 28 April 2005, 16:25

Well i could be wrong as i am no engineer , but me mate Lee Fairweather told me that the wee small hole for the pitot is also the cooler for the compressor . I do know that when i get check pitot come up, my engine is very hot , so i turn off the engine this creates a backflush of sorts restart the engine and watch the temp fall so far its worked out aok . And as Lee knows his engines i have taken his advice on board . I might also add that this usualy occurs when we have a lot of weed around .I am getting the engine serviced next week so i will ask .

TIM · 28 April 2005, 22:15

Quote:

Originally Posted by swginn

You need the Cal2 screen;

Hold Mode and Troll+ for 10 seconds on the Tacho to access the screen. The second menu will be for the Pitot, select No to turn it off.

Just to let you know that using the paddle wheel only will result in inaccurate figures at high speed. The Pitot is more accurate at high speed.

Our setup uses both the paddle & pitot and is very accurate (compared with GPS). I think we've got the transition speed between paddle and pitot sensors set to around 15 kts.

HTH!!

I had asumed that with the paddle wheel that the pitot was not used .... everytime we go out we get 'Check Pitot' I had thought that We were getting this warining because the Pitot wasnt in use .....How do I check this? . If it is connected, or in use ... what could be the problem?????

swginn · 29 April 2005, 08:57

Well the paddle wheel is supposed to be used in conjunction with the pitot, that's why there is a screen in the Calibration2 menu to set the transition speed at which the speed stops being read from the paddle and starts reading from the pitot.

The pitot should be located in the leg of the engine behind a small intake hole at the front of the lower section of the leg. If you are getting alarms saying "check pitot" then it is in use. The problem could be that the intake hole is blocked or something could be stuck in the pitot tube.

Tim Griffin, that is interesting, what you say about the compressor. Seems a bit of a design flaw that such a small hole that is prone to getting blocked is used to cool the compressor. I would appreciate it if you could get more details from Lee on this??

TIM · 29 April 2005, 10:33

thanks I will check it out over the weekend

tim griffin · 29 April 2005, 12:09

Quote:

Originally Posted by swginn

Tim Griffin, that is interesting, what you say about the compressor. Seems a bit of a design flaw that such a small hole that is prone to getting blocked is used to cool the compressor. I would appreciate it if you could get more details from Lee on this??

Nope i was wrong nothing to do with the Pitot hole , the compressor is cooled via the leg as is the engine where it then branches off to the compressor and exits via the tell tale. There is a small grill that can / does get blocked especialy this time of year when there is weed about. HE RECKONS that when i get check Pitot up i have a blockage in the leg and pitot hole (HIGH TEMP) by switching off the engine i am causing a backflush of sorts and this clears it, the only way he could tell what was causing the engine to keep overheating was to get it on the computer.

swginn · 29 April 2005, 14:34

Thanks, that makes sense alright, most of the time if I pick up weed it blocks the pitot first but can block the intake also.