Overheating 1998 Four Winns 454-Vovlo

[drhughes]

My 1998 Four Winns Horizon 240 has a Chevy 454 Big Block engine and a Volvo outdrive. It runs fine at 2000 RPMs but overheats gradually at anything faster.<br /><br />I have had a local mechanic replace the manifolds, risers, thermostat and engine pump... did not fix the problem. He pulled the heads off and thought they looked clean. <br /><br />He is stumped and the closest Four Winns dealer is three hours away. Any ideas on what I should do to test further.<br /><br />Thanks in advance for any suggestions!

 

[Haut Medoc]

Re: Overheating 1998 Four Winns 454-Vovlo

Is it fwc or raw water cooled?

 

[Don S]

Re: Overheating 1998 Four Winns 454-Vovlo

You mentioned your mechanic changed the "Engine Pump". Was that the raw water pump or the engine circulation pump.<br />You probably need to replace at least the impeller in the raw water pump. The circulation pump (what the auto industry calls a water pump) usually isn't the cause for marine overheats.

 

[drhughes]

Re: Overheating 1998 Four Winns 454-Vovlo

I believe it is raw water cooled....draws water from the lake...<br /><br />My mechanic replaced the engine pump.... he pulled apart the impeller and thought it looked ok...<br /><br />Based on a review of recent posts is it possible that it is:

 

[drhughes]

Re: Overheating 1998 Four Winns 454-Vovlo

Is it possible it is:

 

[drhughes]

Re: Overheating 1998 Four Winns 454-Vovlo

Is is possible it is 1. Old Hoses, 2. Pump liner, pump housing, or other impeller leak, or 3. Temp Sensor / Sender.... should I just replace the impeller (even though he says it looks ok - since they should be replaced every year)

 

[drhughes]

Re: Overheating 1998 Four Winns 454-Vovlo

Thanks, Don - I just talked with my mechanic and we are planning to replace the sea pump.... anything else we should check / replace at the same time?

 

[Jilly - 5]

Re: Overheating 1998 Four Winns 454-Vovlo

Check all hoses for softness, especially those on pump intake side. Pumps don't just circulate water passively. They suck hard, causing weak hoses to collapse, constricting water flow.

 

[Jilly - 5]

Re: Overheating 1998 Four Winns 454-Vovlo

Jilly-5 again. Best to check hoses during a quick run-up to WOT. Takes two people.

 

[drhughes]

Re: Overheating 1998 Four Winns 454-Vovlo

Thanks - Jilly 5....I will check those out David