Spurious overheat alarm? 50hp 1999 4 stroke

[kiwiflya]

Hi fellow suzuki/evinrude people.

I have been having a alarm issue.

I have a Evinrude 50hp which i understand is a Suzuki rebranded. Model E50PL4EES.

I can motor at say 4000rpm for half an hour, idle for the next half an hour then when i go to steam home i get a HOT alarm. Aural, light on dash and SLOW mode thanks to the computer.

The alarm seems to occur at higher revs but is intermittent. Its is very frustrating as you can understand and i have reservations about taking the boat out now.

To my knowledge the motor doesnt appear to overheat, i have been able to put my hand on both the cylinder side and the exhaust side without too much of an issue.

Work done includes Both sensors replaced (CHT and Exhaust Manifold), Complete waterpump, baseplate and housing.


Love to hear any suggestions. I am already $800 OUT OF pocket and i am no closer to solving the issue, ie i am back to where i started after that spend.

Anyone had similar?

I am kinda thinking it is that grommet problem that i have read about here up under the power head.

Cheers i advance for any help or suggestions offered.

 

[kiwiflya]

Re: Spurious overheat alarm? 50hp 1999 4 stroke

Have solved my problem

Hi guys, as far as i am concerned this sensor if a design fault of its era.
The new suzuki's dont have the exhaust manifold sensor.

I chased this problem myself till the cows came home spending close to $1000

I left the old sensor in the block but connected a new sensor to the wires from the computer (ecu) and just tucked it away.

I did this after computer diagnostics assured me that is was the gradient alarm that was going off. (had clocked up 38 gradient alarms)

Then i attached a multimeter to the sensor that was still in the block.

I monitor that sensor that way but will soon remove the monitoring once satisfied with the set up.

If the motor does get hot the CHT (cylinder head temp sensor) will go off anyways.

Hope this helps.

 

[99yam40]

Re: Spurious overheat alarm? 50hp 1999 4 stroke

Are you saying it is exhaust high temp it is seeing, or that it is a false temp spike?
Could there be a lean condition be happening causing the exhaust to over heat or too high of octane fuel being used(slower burning)?

 

[kiwiflya]

Re: Spurious overheat alarm? 50hp 1999 4 stroke

When i say exhaust manifold i am saying the water around the manifold so its not measuring exhaust gas or the like.

The fuel and air input is monitored so i cant really see how it could be burning lean. An inspection of the plugs will hopefully back this up. I have been monitoring the temperature via a multi meter. Resistance decreases with temp and i am happy with the values i am seeing. Not seeing any sudden spikes as would be expected with what the alarm and sensor are designed for.

I guess the fact that this feature has been dropped on the later models is testament to this being an extra piece of monitoring that isnt really required nor beneficial. In my case we cant rule out that the ECU is not performing correctly in response to the sensors input. Saying that im not wanting to replace the entire ECU when i have a work around such as this.

Be great if Suzuki/Evinrude came out with a directive or some advice on this though.

My mechanic was ready to pull the head. Good riddens to the gradient alarm.

If all else fails the Cylinder head temp alarm will save me, fingers crossed.

p.s my service man, a different mechanic to the one i took the boat too with this problem saw no evidence of running lean.

Hope this helps other in my situation chasing stupid alarms.

 

[kiwiflya]

Re: Spurious overheat alarm? 50hp 1999 4 stroke

Oh so to answer the question, the alarm was being triggered by an apparent temp spike over a too short a period of time. (values set out by suzuki). ie gradient alarm