www.iFourWinns.com

Not sure but you can look for OMC manuals on ebay....
Keep in mind also the 94-98s were part of the joint venture years with Volvo so these models (Volvo Cobra SX and OMC Cobra) were identical in those years. Meaning that a Volvo service manual should work for yours. Keep in mine that sometimes even if the boat is a '95 the engine package could be a '94.
I've seen both Volvo manuals and OMC manuals and in my humble opinion the OMC ones are much better written and more clear.

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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

Hello,
today i did a measurement of the block temperature by using the thermometer directly on the metal.
I compared it with the temperature which is shown on gauge. I could see, that the temperature was almost identical.

While idling, the temperature rises slowly to something between 145°F and 165°F. While planing the themperature decreases to 120°F - 130°F.


Now, all in all I think, the temp sender is the right one. But why does the temperature decreases while planing. The thermostate is brand new and the bypass is clean.

Actually the water temperature of the rhine river is between 65°F and 68°F.

Futhermore I recognize that the hose of the thermostate to the waterpump is realy hard.
Is that normal?

When you plane the boat, the increase in RPM greatly increases the volume of cold water being pumped through the engine and manifolds. So it can actually run a bit cooler on plane. In my boat with the 160 F thermostat, (with a new stat not one getting sticky) it idles at about 160, when planing it may stay there or a bit cooler. When I stop and go back to idle, it will go up to 175 or and after a minute or two of idling back to 160. When the thermostat is getting sticky, it will idle at about 130, then hit 160 on plane, but may drop back down to 130 again. Your river water is pretty cold. Here the salt water bay that I boat in is only a bit warmer, 73 degrees F.

The hard hose I'm not sure about....you mean when the engine is running? If so it should be firm because water is being pumped through at a high rate.

_________________
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

Meanwhile I have contacted my boatdealer and asked for an repair-appointment.
They know my problem and ordered already a new temp sender. Furthermore I told them the fact of the solid hose.
Currently I got no answer of them.

I'll wait.

Hello,
here's an update.
Today I removed my thermostate housing to clean it up once again.
And I've found some small parts of an impeller in the bypass.
I removed them and now the engine is runnig at a constant temperature.
Today I could'nt measure the temperature. After planing a long distance I can touch the engine and the exhausts for some time. So I think the temperature is not higher than round about 70°C to 80°C.

Next time I'll look at the impeller and a matching temp sender.
I'm glad that I found the problem.
Thank you for the nice posts and the constructive help.