1986 30 ft Sea Ray twin 350 heating problem

[Nev'r Enuff]

I own a 1986 Sea Ray Sundance with a heating up problem we have exhausted our intellengence!!! When the RPM is below 1000 and over 4300 it heats up. When I run at 700 rpm's the heat gauge will climb up real fast, as soon as I bring the throttle up to 1100 it starts to cool down. I've rep[laced the water pump, new water pickup hose and removed the thermostat (which is now replaced since it still overheated). Anyone else ever see this problem. I'm looking at the power steering cooler and any other place Zebra mussles could be plugging the waterway!! The boat just came out of the water yesterday so its time to tear it apart. Any suggestions please..

 

[Don S]

Re: 1986 30 ft Sea Ray twin 350 heating problem

I've rep[laced the water pump,

Which water pump? Many call the circ pump a water pump, hopefully you are talking about the raw water pump in the outdrive ???????

 

[chiefalen]

Re: 1986 30 ft Sea Ray twin 350 heating problem

Impeller in the out drive, when changed last? That would be the first thing i would do.

Risers on that motor looked at,changed last? Second place i would look.

That boat have flappers. It could have fallen off blocking the exhaust. Third place i would look when the riser is off.

And yes any heat exchanger needs to be cleaned out every couple of years they are known to get blocked up.

 

[Nev'r Enuff]

Re: 1986 30 ft Sea Ray twin 350 heating problem

Impeller in the out drive, when changed last? That would be the first thing i would do.

Risers on that motor looked at,changed last? Second place i would look.

That boat have flappers. It could have fallen off blocking the exhaust. Third place i would look when the riser is off.

And yes any heat exchanger needs to be cleaned out every couple of years they are known to get blocked up.

Chiefalen the first thing is I did change the whole water pump assembly in the spring, now I will take the risers off and also check the flappers. Thanks for the advise. While the manifold is off I will take the power steering cooler off and check.

 

[Polar_Bus]

Re: 1986 30 ft Sea Ray twin 350 heating problem

One other comment, you mentioned you "removed" the thermostat as a course of action to overheating. NEVER completely remove a thermostat. This acually festers inconsistant cooling flow and can generate steam pockets, ultimately causing abrupt overheating, or rapid cool downs. GM engines need a thermostat to slightly create a restriction to keep flow consistant.

 

[rodbolt]

Re: 1986 30 ft Sea Ray twin 350 heating problem

over the years SeaRay has made V drives,inline inboard and a few sterndrive models in the 30Ft range.
first we need to know what setup YOU have as we cannot see it, my magic wand is broke and DonS lost his Crystal ball .
next we need to know if it has freshwater cooling,if so full or half system, sea water strainers,closed cooling,clutch oil,engine oil and any powersteering oil coolers.

 

[Nev'r Enuff]

Re: 1986 30 ft Sea Ray twin 350 heating problem

over the years SeaRay has made V drives,inline inboard and a few sterndrive models in the 30Ft range.
first we need to know what setup YOU have as we cannot see it, my magic wand is broke and DonS lost his Crystal ball .
next we need to know if it has freshwater cooling,if so full or half system, sea water strainers,closed cooling,clutch oil,engine oil and any powersteering oil coolers.

Yes it is a outdrive boat with no closed cooling system. Always fresh water(Lake St Clair). This has been an issue for 3 summers and now I have it at home and will start to diagnose. Any help will be appreciated.