1. Engine

Note: I insert records as I come across good advice in current email threads or as I get a chance to review the archives. For that reason all elements of the index are not populated. If any C470 owner does the research and sends me text for a record, I'll include that with attribution. ...Joe

1.2. Raw water system
1.2.1. Raw water pump
1.2.1.1 Raw water pump impeller
Problem: Changing the impeller.
Advice:
When you access the engine from the galley, below the stairs, if you have a mirror (available at auto stores and some hardware stores) that extends and that flexes at the mirror in three dimensions, you can set that at the aft end of the galley storage area below the companionway stairs and aim it at the cover of the raw water pump (impeller) compartment.  I also use a flashlight that has a head that can flex, but only in one dimension.  I am able to aim the flashlight toward the impeller compartment to provide enough light for me to see what I am doing in the mirror.  Still it is not easy.  You can also feel, without seeing, the screws to the impeller cover by reaching around with your right hand.
 
Once the impeller cover is off, I have found that the best tool with which to extract the impeller is a bent-nose pliers.  I grab one blade at a time and wiggle it out -- generally takes me at least an hour of this because the impeller does not want to come out without a fight.  Keep the A/C on high!  However, the impellers I have replaced have been totally in tact (dumb me???). If yours has some missing blades, it might be an easier job.  I have since bought an impeller puller for the next time.
 
By the way, you will probably want to find out where the broken impeller blades went -- usually to the heat exchanger -- and extract them as soon as possible so they don't go farther into the engine.  I have not taken off the heat exchanger on Nirvana, but when we did it at Larry Berlin's class, it did not seem all that bad a task.  If you have an engine manual, it helps because of the exploded views.  Larry Berlin recommended taking pictures of each step of whatever you're doing on the engine so you can see how it should look when it goes back together.
 
Maybe I'm just not adept, but I have also not had that easy a time inserting the new impeller.  Yes, I do cover it with petroleum jelly and pre-bend the blades with a zip tie.  However, it usually takes me several attempts to get it to go in.  Also, don't forget to put some petroleum jelly on the o-ring in the housing that the cover fits against -- best to replace it, too -- before securing the cover.
Owner: Van Bussman
Boat:
Date: 8 June 2008

Advice:
2 tricks I use that work.  1)  use a zip tie to compress the impeller to a small diameter with the rotation orientation correct.  As you install the impeller, the zip tie slides off.  2)  I use KY jelly to lube the impeller and housing because it is water soluble.  I also use speedseal.  It is a great product.
Owner: Robert Taylor
Boat: Vixen; 130
Date: 7 Nov 09

Problem:
Getting access to the raw water pump impeller.
Advice:
The raw water pump has a Speedseal and that makes an agonizing job into just one that is an exercise in contortions with a few "oh, darn's" thrown in.
Owner: Jim Wohlleber
Boat: BECKONING...; 76
Date: 20 Mardh 2009

Problem: Extracting the impeller in the raw water pump.
Advice:
The Jabsco impeller puller part number is 50070.
Owner: Robert Taylor
Boat: Vixen; 130
Date: 22 Jun 08

1.2.1.2 Low raw water flow alarm
Problem: Alarm for low raw water flow
Advice:
Go to Hamilton Marine and do a search for Aqua Alarm. This is a unit that you install in your seawater feed line after your strainer. When the flow of water falls below a limit you set the alarm goes off and you get to shut down the generator or engine before it eats an impeller. I install one on my generator and it works great. Once you have it installed and a clean strainer, start the generator then close the seacock to about halfway then set the alarm so it goes off, tighten the screw and you are done. Re-open the seacock fully from now on whenever your water flow gets to be half of normal the alarm goes off, shut down the generator, clean the strainer/intake, fire it back up. No more impeller parts to clean out! They make two sizes one for 1/2"-1 1/2" and a 2" model. The only thing I changed was the piezo buzzer for a 102 decibel one.
Owner: Bill Martinelli
Boat: Voyager; 11
Date: 28 Nov 08

1.2.2 Heat Exchanger
Problem:
How to service the heat exchanger.
Advice:
  • If you have lost parts of the impeller and the temperature of the engine is maintained at normal ranges, leave the heat exchanger alone as you may cause more problems than you will fix. Save working on the heat exchanger to when you really need it.
  • It is likely that the vanes broke off in small pieces that will flush through the system. Larger pieces that will not fit through the heat exchange tubes will collect at the input (stern) end of the heat exchanger.
Cleaning the heat exchanger tubes:
  • DO NOT use any type of strong alkali or acid (including citric acid-based) cleaners to clean the scale off the heat exchanger. The Aluminum and Copper parts will very likely be damaged or even dissolved completely.
  • Buy long (~18-24") small (~ 3-mm dia) pipe cleaning brushes with plastic bristles to clean out the heat exchanger tubes. These brushes can be bought at plumbing supply, Home Depot, etc. stores.
  • Remove front and rear end caps from the heat exchanger; leaving heat exchanger in place.
  • Pass tube brushes through.

Fuel injector (high-pressure) pump lift pump.
Yanmar uses an electric lift pump built into the injector pump. When this pump goes out, the fuel injector pump needs to be removed from the engine to replace the lift pump!

Source:
Greg Dennis; SV Rebel Son; Yanmar diesel mechanic.
Date: 5 Mar 10

1.4. Fresh water cooling system
1.4.1. Thermostat
Advice:
Yanmar uses a special "double action" thermostat. (as the cooling flow opens, the bypass flow closes). It may be available from other sources, but it is not a standard automotive replacement part.
Owner: Jim Seemann
Boat: Pipe Dream; 143
Date: 28 Oct 09

1.4.2 Engine overheating
Problem:
Engine over temperature alarm with good raw water flow.
Advice: The overtemp alarm indicates the coolant is hot. This could be caused by the raw water system not cooling the engine or a problem with the coolant. In my case, it was the coolant. I wasn't thinking; the coolant bottle is an overflow collector, not a coolant source. I didn't stop to check if there was in fact adequate coolant in the engine. I ended up pouring over a gallon of coolant into the engine. Started the engine and everything seemed to work fine. Shut it down, checked the coolant and had to add almost a quart. So where was the coolant going? There is a pet cock on the coolant line where it goes into the heat exchanger manifold in the hot water heater. When I winterized the boat's (not engine's) fresh water system prior to leaving the marina, I must have hit and opened the pet cock while I was draining the hot water heater. The pressurized coolant leaked out the pet cock and into the bilge.
Owner: Mike Davis
Boat: Ayewash, #150
Date: 2 May 2009

1.4.3 Antifreeze

1.4.4 Removing water hoses
Problem: Difficulty removing hoses.
Advice:
The easiest way I have found to get any hose off is to wrap a wash rag around the those after removing the clamp.  Then pour real hot water on the rag.  Let it sit for about 3 or 4 minutes to soften the hose material.  Then it usually comes off fairly easy. 
Owner: Robert Taylor
Boat: Vixen; 130

1.5 Motor mounts
Problem: Motor mount is in the way of getting access to the raw water pump attachment bolts.
Advice:
In the unlikely event that you have to change the pump that drives the impeller, the standard forward engine mount on the port side must be removed, after marking carefully its position so that exact replacement is possible so as to not have to realign the prop shaft after the job is done.  However, it's always a good idea to check the prop shaft alignment every year anyway.
Owner: Van Bussman
Boat:
Date: 26 June 2008

Problem: Replacement motor mount that gives access to raw water pump attachment bolts.
Advice: Mastry has an engine mount replacement which makes water pump repairs very easy.  The mount is ONLY the port side forward mount. My local Yanmar guy removed the old one, put the new one in place and tidied up in about 2 hours.  As of now, I have not had to replace the water pump. www.mastry.com!!!  Ask them for their engine mount which facilitates the water pump removal. They will know what you want (they build the mount, not Yanmar). Have your engine model number and serial number handy when you contact them. The mount is a bit pricey but the water-pump removal issue is resolved when it is in place.
Owner: Jim Wohlleber
Boat: BECKONING...; 76
Date: 20 Mardh 2009


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