Temp gauge problem?! Four Winns Horizon 192 CB - 1995

ach1982 · **Joined:** Tue Jun 10, 2014 7:01 am **Posts:** 80

Hello,
I'm am a owner of a FW Horizon 192CB, model year '95. The engine is an OMC Cobra 4.3 GL and I have a problem with the temp gauge.
This gauge does'nt show the right temperature.
While running the boat, the gauge shows the lowest temperature. After stopping the machine, the temperature will rise slowly.
The engine and both exhausts are really warm (not hot), even while driving. I would say, that they have the same temperature. So I am convinced, that the thermostate is working.

Initially I replaced the thermostate (160°F, fresh water). The result was, that the engine and both exhausts are warm but the temperature gauge does not show any temperature while running the engine. It was the same result like before.

My next step was the replacement of the temp sender. I ordered the part with the number 3852029 - I think, now it's a volvo penta sender. The same should be the Sierra 18-5898 sender. This part number was mentioned in the parts-cataloque for OMC Cobra parts.

The result of this replacement was, that the gauge now will show 130°F permanent while running the engine, when i stop, the temperature will rise slowly to 150°F. But when I have installed the 160°F thermostate, the gauge has to show 160°F permanent while running ?!
Between both replacement steps I short the wire of the temp gauge to ground, to test the gauge. It works! It shows the max temp.

Now I do not know, what could be the problem. Is it the gauge, the engine, the whole cooling system, the temp sender. I'm desperate!

I have some questions:
- Does anybody of you had/has the same problem? Is there a solution?
- Do I need a special temp sender for my Four Winns cockpit?

I need some help, in germany no dealer and no workshop in my surrounding can help me with my problem.

Finally, I would like to excuse me for my bad English. I come from Germany and this is my first post in this forum.

Best regards

ach1982

Borchik · **Posted:** Tue Jun 10, 2014 9:11 am

The engine will not necessarily run at 160 just because you have that thermostat in there. Sea water temp has a lot of influence on what your internal engine temp will be. Whenever I am diagnosing cooling problems I always check temps on certain areas of the block with an infrared heat gun to double check what the gauge tells me.

rpengr · **Posted:** Tue Jun 10, 2014 10:19 am

There is always some water bypassing the thermostat even when it is closed, so you will usually run lower than 160 unless you are running hard for a while. Where are you from...how cold is your lake water?

Cap'n Morgan · **Posted:** Tue Jun 10, 2014 10:55 am

rpengr wrote:

Where are you from...how cold is your lake water?

ach1982 wrote:

I need some help, in germany no dealer and no workshop in my surrounding can help me with my problem.
Finally, I would like to excuse me for my bad English. I come from Germany and this is my first post in this forum.

LouC · **Posted:** Tue Jun 10, 2014 11:14 am

Get an IR temp gun and take a reading of the intake manifold right under the thermostat housing, this temp will be with 10* of the gauge temp if all is well. Mine runs at 160-165, the reading I get from the manifold is 150-155.
If its really low, all it takes is a bit or rust or sand and it will keep the stat from closing. It will then read 100-120 at idle and low speeds and will not hit 160 till you run on plane.
Also if debris cloggs the by pass in the Thermo housing you can also get cool running.
The thermostats not closing has been a chronic problem here in salt water.

ach1982 · **Joined:** Tue Jun 10, 2014 7:01 am **Posts:** 80

Hi,
thank you for your fast response.
I'm from germany. I live in the surrounding of Frankfurt/Main and I drive my boat in the Rhine-River.

The water temperture is round about 18°C to 20°C.

But I think my delaration in my post is a bit wrong.
With my first temp sender the gauge will show no temperature at all.
With the second one, I mentioned before, the temperature gauge will show 120°F to 130°F when I start the ignition.

When I stop the engine, the gauge temperature will rise up slowly.

Is there a correlation between the ground connection of the gauge and the engine while running?
My test with the temp sender wire to ground is fine...

ach1982 · **Joined:** Tue Jun 10, 2014 7:01 am **Posts:** 80

LouC wrote:

Also if debris cloggs the by pass in the Thermo housing you can also get cool running.

I thought if the bypass is blocked, the engine gets too hot.

ric · **Posted:** Tue Jun 10, 2014 2:07 pm

Being a 1992 boat there's a very good chance the gauge is bad.

ach1982 · **Joined:** Tue Jun 10, 2014 7:01 am **Posts:** 80

ric wrote:

Being a 1992 boat there's a very good chance the gauge is bad.

Why 1992?
Is there a special problem?

The `92 Model has other instruments.

ach1982 · **Joined:** Tue Jun 10, 2014 7:01 am **Posts:** 80

does anybody know, if my temp sender matches to the gauge/engine?

ric · **Posted:** Tue Jun 10, 2014 2:41 pm

To be quite honest, for anything original to the boat that's electrical to still be working after 20 years is a miracle. You can get a new gauge kit for around $150 usd. I had to replace the gauges on my 2000 Horizon 180, half were dead.
http://faria-instruments.com/products.p ... e=2_boxSet

LouC · **Posted:** Tue Jun 10, 2014 3:42 pm

well....my boat has 26 year old Medallion gauges....has been in a salt water environment as long as I have owned it, probably before (we're talking at least 15 years) and all the gauges work.
OK back to the problem....
when you say...it goes up to 120-130 when you switch on the ignition, is that after running the engine right before, or is that with a cold, not run engine? Because if you have not run it and it goes to 120-130 when you switch on the ignition, something is wrong for sure either with the gauge, wiring, or sending unit....
If you have just run it, then that's probably normal, but its still running too cool. Mine has always run between 160-175 at the most, and that 175 is after coming off plane, it will cool down to 165 soon after. I have had to replace thermostats at least 5-6 times over the 12 years I have run this boat for this same exact problem. But when I've changed them, the temperature goes right back to normal. The gauge and sending unit on the engine, are both original, 26 years old.
Looking at the back side of the gauge, are the terminals free of corrosion, are the connections tight? If you wiggle them with the key on, and someone watching the gauge, does the reading change?

Keep in mind for the gauge to read properly it needs:
12V power from the ignition switch
a signal (resistance) from the sending unit
a ground path
if any one of these are corroded, with high resistance, it can cause problems.

When you replaced the sender, did you use sealer on it or anything on the threads? If so it may disrupt the ground path for the sending unit.
I'd take a look at the bypass passage and in fact all the passages in the thermostat housing, make sure none are clogged. Run a coat hanger wire through all of them.

ric · **Posted:** Tue Jun 10, 2014 9:32 pm

They work, but are they accurate? That's the question.

ach1982 · **Joined:** Tue Jun 10, 2014 7:01 am **Posts:** 80

does anybody know, if my temp sender (VP 3852029) matches to the gauge/engine?
My dealer told me, that this sender substitutes the original OMC with the same number. It should also be equivalent with the sierra 18-5898 he said.

This weekend I'll open the thermostate housing to clean up the probably clogged bypass.
Furthermore I'll check the wire from the sensor to the plug in the cockpit.

Cap'n Morgan · **Posted:** Wed Jun 11, 2014 8:54 am

ach1982 wrote:

does anybody know, if my temp sender (VP 3852029) matches to the gauge/engine?
My dealer told me, that this sender substitutes the original OMC with the same number. It should also be equivalent with the sierra 18-5898 he said.

It will "match" as long as your gauge functions properly.
Your dealer is correct.

www.iFourWinns.com

Temp gauge problem?! Four Winns Horizon 192 CB - 1995

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