Leaking Thermostat

[Nautical]

Heat retention would be my thought as well.In a confined area the vst would tend to retain heat. However poly olefins are used extensively in many intricate fuel pumps etc.So its do able. Yamaha had some bad cups prob due to formula issues.You are prob correct..heat retention..good thought.

[DennisG01]

Interesting conversation. Just to throw out another thought... "plastic" intake manifolds have been used successfully on automobiles for quite a while, now, and they run hotter than marine engines. I think the important thing here is the TYPE of plastic being used. What we typically think of as "plastic"... no, not a good idea. But if we think more terms of a "composite" structure, then that might be a very viable alternative.

[boscoe99]

Interesting conversation. Just to throw out another thought... "plastic" intake manifolds have been used successfully on automobiles for quite a while, now, and they run hotter than marine engines. I think the important thing here is the TYPE of plastic being used. What we typically think of as "plastic"... no, not a good idea. But if we think more terms of a "composite" structure, then that might be a very viable alternative.

Yes, there is plastic and then there is plastic.

One is a plastic bag that falls apart before I can get home with just a loaf of bread in it.

One is a plastic container, say holding a GPS, that takes all but a sawzall to get it open. Packaging from hell I say.

A fiberglass boat is a plastic boat. OK to boat in a plastic boat but God forbid that a plastic throughhull is used in a plastic boat.

Air liners that we fly around in at 500 plus knots, in thunderstorms and hail, are being made more and more of plastics.

I long for the day when there is just one fuel pump in a plastic tank in the boat. The hell with the VST, aluminum or plastic. Now will a plastic VST cause the fuel to be hotter or cooler? Results are not always what they are assumed to be. Plastic might be cooler if engine heat is prevented from getting in. Or, aluminum might be cooler if it allows fuel heat to be radiated out.

I like how threads morph from one subject to another. Keeps us thinking.

Oh, remember the movie The Graduate? Dustin Hoffman being seduced by Mrs Robinson. The future is in plastics.

[Nautical]

Yes, one in the tank is ideal.. The reason I think this is not so is because outboard engine is a product unto itself.Made to fit many boats of different manufacture. In order to avoid confusion outboard manufacturers cannot dictate to the boat manufacturers what fuel pump to use. For example GM makes a car exclusively from top to bottom . Boat manufacturers buy engines from another corporate source not knowing what will propel it . In other words outboards are made universal to all boats ..that is why I believe they are self contained and do not want to deal with an external component they have no control over.Yes outboard engine manufacturers do own boat companies and that is a bit of an oxymoron.I once had a Yamaha hull powered by a mercury optimax inboard power plant. The manual was very specific where Yamaha ended its warranty and where mercury started theirs.It was at the fuel line .