Trojan Boat Forum

i was driving my 1982 33ft carver twin 440's yesterday and on one engine the risers got real hot up on plain??? (but not the block) so i got that little heat gun out and checked them while the wife got her back up on plain, and what i found was >>
the 1" hose inlet hose for my raw water was collapsed just before the raw water pump.. now it would really collapse at 2800rpm's
at 1800rpms not so bad..
i'm thinking this is what is wrong ???
just a bad hose or what do you all think?

A collapsed hose is definately not a good thing and should be replaced. Is it just aged or the wrong type of hose? The proper hose will not collapse. Do you have fresh water cooling (closed system with heat exchanger and antifreeze) or raw water cooling?

just an old hose that is going to get a brand new one today. the engine is not raw water cooled ,, it is closed

If memory serves me, in your application, the engine heat exchanger is the first to benefit from the raw water. After drawing heat from there, warmer water then flows to the oil coolers, manifolds, then elbows. Any decrease in volume will affect the cooling system's ability to remove heat further down the circuit. Hope the easy fix solves the issue.

as to hoses thay do collaps we use 4" and 5" marine wire wound supper flex on hydrolic elevators pump units 1.5' long suction line from tank to pump avg life is 5 years then the inner wall collaps another example the flex line on your brakes on any moter vech will over time will do the same the inner ligning will seperate from expansion then without the preasure it will callaps and your caliper or wheel cly will not retract when you take your foot off the petel (when in dought chang it out)

You need to use a good grade marine hose with wire in it , nothing you will find at most auto part stores will work . marine exhust hose works good.

I also agree about the hose but just for giggles you might take a dive or pull the boat to check the raw water intake grates on the bottom of the boat to make sure they haven't been mashed in, covered with 10 coats of bottom paint or plugged up with plastic or garbage. I have experienced all of these and they had the same symptoms as what you discribe. It may not be any of these but it's better to check than to starve an engine.

can you believe this we all agree on this .... change with a good grade marine wire backed hose and clean your scoops out and run her.

The entire sea water flow path needs to be checked periodically. No question a sea water intake hose has to be the marine non-collapsing wire wound type. Wowzer 52 is right about the grate..I've also seen grates covered over with barnacles, and I had a through hull fitting with some kind of hard deposit in it that looked like calcium that had closed off all but 1/4 inch of the opening. If you have a problem, take it all apart and look through it!