[donald roth]

“Ghost” pieces of impeller can hide in the raw water works, and even on the pump intake side.  <br />Have you looked inside the heat exchanger?  Broken off zincs can block flow there, and while there check the condition of the tubes.                                       Go through the entire raw water circuit from intake fitting to exhaust mixer.

[donald roth]

Have you considered that you may be overpropped?  <br />Fuel burn seems high for a low hp B motor, and black smoke is another indicator.  

1 user thanked author for this post.

browntw.79

[donald roth]

Recommended coolant change interval is 3 years.

Your motor looks like it has been running on water for a while.

Heat exchanger leaking?

[donald roth]

Plumbing supply houses carry a T handle torque wrench for just this purpose.  It is designed for use on no hub fittings, and I don’t know what the preset torque setting is, but it has served me well in my boats engine room, my cars and trucks, as well as plumbing applications.

1 user thanked author for this post.

Steve Lewis

[donald roth]

Food grade silicone spray is a great corrosion inhibitor.  It does not leave a sticky coating when it dries.

[donald roth]

You absolutely need a 24 volt alternator in a 24 volt system.                           Check the alternator output first to verify what it’s putting out vs what is stamped on the plate.

 

 

[donald roth]

There’s a second turbo gasket under the blank on top of the exhaust manifold that can be easily overlooked.  A pressure test would have shown it.

[donald roth]

I’d be worried about that loose motor mount, old swollen hoses, and crushed up air filter as well.

 

[donald roth]

Metal in the return lines are probably debris that were in the lines when the system was installed.  If the HP pump was spitting metal, there would be other obvious symptoms.  If the debris were coming from the tanks, your filtration system has failed miserably, but those debris couldn’t pass through the pump without causing damages anyway.

 

[donald roth]

Are you filling crankcase with correct amount of oil?  Dipstick marks can be misleading.  I think there’s an article about that in the “Tips” section.

 

[donald roth]

Pressure test transmission oil cooler before you start throwing dollars at the fuel system.

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Blair Bugher

[donald roth]

If there’s not enough water from the dock faucet, you’ll first see the hose collapse.  This doesn’t mean it’s not passing water though. Just that it’s drawing a suction.  It helps to use a large diameter hose and don’t choke the flow with small valves and fittings.  I’ve been flushing my motors like that for many years,  have never had any problems with impellers.  Leaving the seacock open insures no problems, like someone shutting off the hose, or hose kinking.  One thing to look at is possibly changing your HE zinc to aluminum, as it will be parked pickled in fresh water most of the time.

 

[donald roth]

You’re likely overpropped, but hunting in the dark without proper data.   You’ll need accurate rpm, egt, and boost pressure numbers.  <br />A peek at the exhaust side of the turbos would be my very first move.

 

 

 

[donald roth]

Any time someone have to replace a turbo, I’ve got to ask why it failed?   Your problem likely goes beyond sealant choice.  Turbos are very simple, and should provide many thousands of hours service without problems, provided that they are correctly installed, particularly in relation to exhaust geometry.  

 

[donald roth]

In first post you said, “Installed new turbo”  —Why?   Turbos don’t just go bad for no reason!<br />The answer could be key to your problem.

 

[donald roth]

You could drill and tap the fiberglass tube behind the gland to accept a water feed fitting.

Id recommend to remove the unknown packing and reinstall with a high quality product according to Tony’s Tips instructions.

Polishing up the shaft where it goes through the packing might help too.

 

 

[donald roth]

Have a look at the raw water pump impellers.  Just a couple of blades missing could cause problems at high speeds, and not at slow.

Leftover impeller bits from previous impellers may still be loose in the raw water system.

Next look for hoses that may be kinked, delaminated, or are collapsing under high suction.

Raw water and exhaust routing are necessarily different on P and S engines, make sure that all is kosher there too, especially on the side with the longer runs.

 

[donald roth]

Seaboard markets a water flow alarm that’s pretty generic, it has pipe threads to install into a tee across the flow.  Most installations I’ve seen are located in the area just past the raw water pump, but I prefer to place it at the end of the raw water path, just before the wet elbow.  In this position it will indicate any faults in the entire raw system (blown hoses etc) as well as water pump function and intake restriction.  The housing is plastic, so mount it in a protected position.  I broke one right off while removing an impeller!  I made a long 360* loop in the hose between the heat exchanger and wet elbow with the sensor mounted in the low apex of the loop.   This also helped eliminate false alarm chirps created when small amounts of air entered the intake.

 

 

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Lew

[donald roth]

I replace the impeller annually, call it cheap insurance.                                         <br />Some guys replace every other year, some others when it shows signs of wear, but I don’t know anybody that will run one for 5 years.                                         Its a moving part, it flexes with every rotation, wear is normal and expected!

 

 

[donald roth]

Have you cleaned the tanks?  Thats where the crud is coming from, your efforts will be futile until the tanks are clean, or you install a filtration system that has a high enough capacity to accomplish that, and a water separator. 

[Author]

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