www.iFourWinns.com

Sigh.

This happened one time last year as well. Cruising along about 4000 rpm. Temp jumps from middle of the gauge (175) to far right within seconds.

This time the engine actually shut down to idle on it's own. So, I'm think it's not a defective gauge. Once I went back to idle the temp dropped RAPIDLY. Within 30 seconds, back to the left side of the gauge.

Cruised on, no further issues all day yesterday or today.

Over the winter I replaced the thermostat, belt, did a complete tune up, etc.

Any suggestions on what to check? Possible that the water wasn't being sucked in through the outdrive at the speed I was cruising (30 mph)?

Craig C.

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2003 Vista 248, VP 5.0 GXi-C, DP

A momentary overheat like that could be the result of debris clogging or getting sucked into the water intakes...plastic bags...kelp/seaweed...eel grass....etc...but if it happens on a consistent basis...it may be time to go through the cooling system...in order for these to cool properly lots of water has to get in (impeller...thermostat...) and out (manifolds/risers). One good way to trouble shoot is to follow the manual's procedures. I don't have a Volvo but in my OMC manual there is a test for when you have the boat in the water...to make sure the impeller is pumping enough water...that's where I would start...it's got to shoot a column of water up to a certain height...might just take a look at the impeller, housing and wear plate. The thermostat you did already...
With the engine idling after warm up check the temp of the risers...they should be warm but not so hot that you can't put your hand on them...then after a run...check again...they may be a bit hotter but if they are really hot you might have clogging in one side or the other...a good infared thermometer test gun from Radio Shack is a great diagnost tool...you can check the temp of the thermo housing...risers...etc without touching anything.

If the impeller has not been done in the last 2 years I'd look at that first...I do mine once a year and have never had a heating problem...we have barnacales here and I have to take the impeller out of the drive to flush the little barnacles out of the water intakes (easier than splitting the upper and lower) and I put in a new one and then keep the old ones for spares. The OMC Cobra has a nice easy to service impeller on the rear of the upper gear housing..under a plastic cover...

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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!
Have Vista 238 1999. Returning home some nights from a cruise, pulling in at low rpms the temp gauge shot up and set of alarm when I put on my spot light. Kept doing it. Let it go until next spring and made sure battery cables were hooked up to the batteries as good as you can do. Problem went away!
Cap't Zero

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CAPTAIN ZERO

That is... very strange. I have a hard time rationalizing a cause-effect relationship between a poor battery connection and engine temperature. Did you by any chance change the water pump impeller over the winter as well?

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Martin
04 268 Vista - Knot Again
08 Boston Whaler 130 Sport - Double Good
Previous Boat:
97 278 Vista - Buoy Howdy

If it's the VDO cluster on the boat, maybe it's a ground/ power supply issue and the spotlamp causes a voltage drop; they can be a bit tempremantal/ sensitive to connection quality and voltage!

Graham

That would make sense, an erroneous reading and not an actual overheat situation. thanks

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Martin
04 268 Vista - Knot Again
08 Boston Whaler 130 Sport - Double Good
Previous Boat:
97 278 Vista - Buoy Howdy

this has happened to me twice, both times after running into sandy conditions. when running, one riser was hot to the touch. i have sucessfully fixed this both times by removing the drain plugs in the back of the manifold and using the flushing hose.

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republicans, working hard so you dont have to.

It sounds like you are ingesting sand into the cooling system. Just how shallow is the water? If you have ingested sand then a new water pump impeller would be a good idea.

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Martin
04 268 Vista - Knot Again
08 Boston Whaler 130 Sport - Double Good
Previous Boat:
97 278 Vista - Buoy Howdy