overheat at high speed 1985 force 85 hp

[rafael]

have a 1985 force 85 hp at high speed no water comes out of exhaust and engine overheat new water pump kit and new termostat and still same problem

 

[12Footer]

Re: overheat at high speed 1985 force 85 hp

So far, you haven't wasted any time or money. Those are the primary causes, and only last a couple years anyway, so changing them was a prudent move.<br />Try back-flushing the block with water pressure from the garden hose. It's hard to gett all areas of the system this way,so dissasembly will probably be needed.<br />There may be the pieces of the old impeller,or other obstruction in the cooling circuit...Buy a head gasket, and a set of exaust port plate gaskets, and inspect the water jacket.<br />It's a good idea to do this anyway on most outboards with many hours on them,esspecially,if said engine has seen a lot of salt water use.<br />Salt allways crystalizes in the water jacket. It can't be prevented, only diminished by frequent flushing and products such as "Salt-Away". <br />It may be "due" for a tear-down/ Look-see.

 

[oldboat1]

Re: overheat at high speed 1985 force 85 hp

12footer has it right. You might also test to see if water is getting up to the head by removing the the thermostat and leaving the cover off. You should see a good amount of water either by backflushing or cranking the engine.<br /><br />I'm curious about the issue of overheating at high speed only. Maybe it's a problem specific to your model, but it's kind of counterintuitive. If the waterpump is working well at idle, it should be pumping a much larger volume when the impeller is spinning much faster. Are you sure the engine is overheating at high speed? Similarly, are you sure it's operating at the correct temp at idle, and that water is being pumped? It's possible that the pump assembly isn't quite right -- impeller not secured by key, or housing not airtight on the wearplate.

 

[jimdi@localnet.com]

Re: overheat at high speed 1985 force 85 hp

It sounds like a obstruction or restriction. It high rpm's the water pressure may be forcing the obstruction in tighter - when rpms go down the obstruction opens up to allow water through.