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2006 150 hp opti

S

Steve Hawes

New member
I have twin 150 opti's. At idle both at 58 degree C. At 3000 revs plus both at 35 degree C. At around 2000 revs one motor rises to 50 to 60 degree C and alarm goes off. The water discharge seems to be more from the motor that is alarming.
Should the first option be to change impellor?
As a moored boat, has anybody removed a leg when boat "floating".

thanks

Steve H
 
Hello Steve.

First off do you have a manual?

There is no reason you couldn't drop the lower unit with the boat in the water - at least no mechanical reason that I can think of.

You state you have good "tell-tale" flow from the motor that is alarming. Despite that you could have either a blockage in the water channels, a bad thermostat or a bad poppet valve on that motor.

The tell tale on an Opti ONLY tells you if the water pump is operating and cooling water is getting to the air compressor.

An Opti's cooling system is somewhat different from most other outboards out there.

The lower end is the same but when the water gets to the top of the tube at the base of the power head it is split off into three distinctly different channels.

One feeds over to the air compressor (to cool it) and then out through the tell-tale.

A second feeds a (heat exchanger) which cools the fuel which is recirculated from the fuel rails.

The third stream is fed through the jackets and channels to cool the powerhead itself.

So you can have a perfect tell tale stream but not be getting cooling water to the powerhead - one of the drawbacks of this particular cooling system.

The temperature is monitored by three sensors - one at the compressor and one on each bank of the powerhead.

The powerhead temp is controlled (below about 1500-1800 rpms) by the thermostats and by the poppet above that rpm.

Given you are getting an overheat and alarm at 2000 (that corrects itself at 3000), my first guess would be a poppet that is on it's way out.

And since that is a fairly inexpensive fix so that is where I would start...
 
Hi again Galamb,

As I am in Perth Western Australia and its a long weekend, I cannot source a manual.

These poppet valves - where are they? and how many are there?

I think I may have located two of, and one thermostat, but not 100%
They seem to be on the fuel block or whatever it is called.

thanks again

Steve H
 
Steve,

The poppet valve is at the bottom center starboard side of the block, follow the hose from the top center behind the flywheel down past the heads and under the block towards to the front.
 
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