232 Exhaust Temp Sensors

[ticerob19]

I need to replace both of these sensors on my 232 Limited, the only problem is parts are backordered everywhere until the end of August. The engines are in great mechanical condition, but from my understanding, the boat won't run without these sensors installed. I was wondering if there is anyway I can bypass the sensors so I can at least have my boat for the summer months. Please tell me there is a way to rig something up! I've attached the specific part number below. Thanks and happy boating.

 

[Beachbummer]

Disconnecting the sensor should fix your problem. The sensor is a thermoswitch, and when working correctly will make continuity at 94 to 100C and Break it again on the way down at 80 to 94.

By keeping the sensor disconnected and nothing attached you are simulating a "working" sensor in an engine that is NOT overheating, regardless of temperature.

 

[WREKS]

@ticerob19 If you have not tested the sensors, I would not replace them. You may have a clog in the cooling system.

 

[Beachbummer]

Sensors can be bench tested by placing the temp sending part in water on stove up to temperature and watching the continuity appear at the expected temp.

If you check them cold and they have continuity they need to be replaced.

We rarely hear of these sensors going bad, but it does happen. Cooling clogs are more common, and both at the same time seems a little suspect.

Testing the sensors is a very very good idea.

 

[WREKS]

If you check them cold and they have continuity they need to be replaced.

@Beachbummer Very helpful! Can be tested right at connector without removing engine/exhaust pipes.

 

[ticerob19]

Thanks for all the input. The problem has been diagnosed and it’s certain the sensors are shot beyond usability, like falling apart. Given this, can I run my boat if they’re not even there?

 

[WREKS]

@ticerob19 The sensors protect the engine.

 

[Beachbummer]

If you are certain the boat is running cool I would not have concerns. The same water cooling the engine cools the exhaust. If an issue came up the engine should also overheat. but you are assuming a greater risk that you break something if it does overheat.

Fair warning: I'm the guy that bypasses some safety measures and stays in the pool when the lightning is far away, and only you will suffer the consequences (and reap the benefits) of your actions. If I was you I'd bypass it, but it's your boat that will cook if it goes sideways.

 

[WREKS]

The same water cooling the engine cools the exhaust.

The water divides where the cylinder head meets manifolds: some goes straight to exhaust; some goes to the cylinder cooling water jackets. An Exhaust Thermoswitch and an Engine Thermoswitch. I would make sure engine is not overheating.

 

[Beachbummer]

Well, today I got an Exhaust overtemp signal in my Dash, a Flash of 5,3 with a flashing overtemp. Engine water temp as measured was OK, and engine did not falter or cut out. I heard no beeping or alarm. I was too chicken to stop engine in case it would not restart, as exhaust seemed to be the same fine temp as the other (to the touch), so I wonder if it was the sensor.... Will be doing more troubleshooting on the next outing, I will be placing another external temp sensor very near this one to monitor temp. We'll see. Let us know how yours goes.

 

[WREKS]

@Beachbummer So your original equipment overheat sensor(s) did not put the engine in limp mode but an auxiliary heat sensor registered an overheat? What does 5.3 mean?

 

[Beachbummer]

My added sensors did not register a problem, but the boat indicated engine code 53 and overheat light.

Upon more research this morning, 53 is Exhaust temp sensor malfunction, Accordingo the internet.

No limp mode, although it has gone into limp mode in the past with a "real" overheat.

 

[WREKS]

That leads me to think that an 'exhaust' overheat and an 'engine' overheat are processed differently by the ECU.

 

[Beachbummer]

I agree, i struggle on how there is a exhaust sensor malfunction vs. an overheat. Maybe an intermittent signal a few times? No idea, more exploration will be needed, but the boat is at the marina, so it will be next week for me.

 

[WREKS]

Looking at a Diagnosis Record from YDS, a sensor sends a code and engine hours when certain specifications are not met whereas the overheat warning registers only the engine hours when it switches to limp mode. In the particular record below, I had forgotten to connect the Pulser coil (Code 13) and engine would not start.

Diagnosis Record​	​	​	​
​	Total hours of operation​	89.7​	​
​	Code​	Item​	Occurred​
​	​	Overheat warning​	28.92​
​	13​	Pulser coil​	89.05​

 

[Beachbummer]

What the heck? No weep holes in my exhaust flange. There is a path for water via some hoses around it.

Looks like no holes from factory.

 

[Beachbummer]

Here is the water path

 

[WREKS]

No wonder you got a Code 53.

 

[buckbuck]

@Beachbummer I am pretty sure that is a CA engine that has catalytic convertors. I recall seeing that routing of cooling in my service manual. Just a heads up.

 

[Beachbummer]

Interesting, where would the cat be? I've never noticed them.