www.iFourWinns.com

I was wondering if anyone knew what the normal operating temp range is on a 1992 Horizon 190. I have the owners manual, but all it states is to not run it if the temperature seems high. As This boat is pretty new to me, I have no idea what the range is.
Thanks for any help!

What engine does your 190 have and what temp are you running at?

It has a V8 5.0L OMC cobra.

I seem to be running around 200F.

I have a 5.0 also and it runs a 195 degree thermostat so that temp sounds about right.

Ross

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1999 200 Horizon

Thats a load off my mind. Thank you.

If those boats were closed cooled, that temp would still be a little high, but if they are raw water cooled (no heat exchanger) they are definitly too hot. A raw water cooled OMC or later Volvo usually comes with a 160 thermostat. When the cooling system is working properly, these engines will run at 160-175 normally. 180 and hotter and you have to start checking for problems, like impeller, ex risers+manifolds. My 19 year old V-6 will run right at 160 all day long.

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88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

I checked the impeller and it looks fine almost new looking. Now I will have to figure out how to check the risers+manifolds.

Is this a fresh or salt water boat? If fresh the manifolds/risers can last a long time but eventually corrosion can catch up with them. A quick test is to warm the motor up and rest your hand (carefully) on top of the riser on each side, they should be warm but not uncomfortably hot. After running it at normal speeds, they may be a little warmer but again not really hot to the touch. Salt water the manifolds/risers only last about 5 seasons. IF they are hot you have to remove the risers and inspect for clogging of the cooling passages. At that age it's possible.
Other possible causes: sticky thermo that does not open all the way
loose water pump belt
Impeller housing gasked not properly installed, allowing it to pull in air
Wear plates in impeller worn
Debris in water intake line such as seaweed, eel grass or even parts of a past impeller that started to come apart.

The reason they have to run cooler than a car engine is because it is an "open" or non pressurized system, so water will boil at 212 but you can get localized boiling even when your temp guage is reading 200. The pressurized syetem cars and some boats uses with a 15 lb cap prevents boiling until about 265*F or so.

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88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

It is a fresh water boat. I will check the thermostat (most likely replace just because). I'll do the quick test you spelled out for me and see how hot it is to the touch. Thanks for all the info!

If you do change the thermostat, make sure to use an OE one not a car one and note that it is retained in the housing by a rubber ring. This can be crudded up with rust and you may barely be able to tell that's what's holding it in there. You pry the ring out with a small thin screwdriver. Be careful removing the housing bolts esp if they have not been removed in a long time. I didn't have any trouble getting mine out even with salt water use. For parts you can go to an Evinrude/Johnson dealer, they get the parts from Bombardier which now owns Evinrude/Johnson.
With the risers, if you do remove them check for clogging and also corrosion of the surface where the gasket sits, if that is very rotted I'd change them. The parts are not cheap but if the manifold rots through you will get water ingestion in the engine which will trash it.
Good luck and glad to be of help.

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88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

Bdalton, you might as well change that impeller out, too. I know you said you checked it, but for the very low cost (along with the fact that you are already going to have it apart) you might as well replace it. Could be a problem with it that isn't visible to the naked eye.

Barefooter, are you sure that the thermostat is actually a 195-degree thermostat? I've never heard of one that high, but by no means am I the god of engines. Just doesn't sound right, especially given LouC's correct statement about the pure water boiling at a little over 200 degrees. I think I'd get that system checked out, and get a much cooler thermostat if it really is rated for that temp.

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Paul
2007 Four Winns Horizon 220
Mercruiser 350 Mag MPI w/ Bravo III Drive
2004 Ford Explorer Limited (V8-AWD)
Pomme de Terre Lake (Southwest Missouri)

Well, I found out the thermostat was corroded and not opening up all the way. I have replaced it and now the boat runs at a cool 150. Thanks for all the help!