Just a bunch of well deserved maintenance

Note that Botany Bay has a V-drive with the engine facing aft so the transmission is on the forward end of the engine.

The initial observations of issues prior to taking anything apart are as follows:
     - Small but significant exhaust leak at the forward (closest to the transmission) flange between the cylinder head (steel) and the closed circuit cooled exhaust manifold (aluminum). Dark black oily sludge is on the cylinder head and down the side of the block. 
     - Small discoloration of the threads where the water is injected into the exhaust system
     - At high load the engine seems to thermally soak at about 190F instead of the normal 180-185F
     - Exhaust appears to leave more residue on stern than I remember
     - General peeling of paint 
Additionally, the following items should be changed/serviced in general after 5 years:
     - Injector Servicing
     - Valve Lash Check
     - Heat Exchanger Clean Out
     - Thermostat
     - Check all hoses, replace as necessary
The following items should be changed/serviced every year:
     - Replace Raw Water Impeller
     - Replace Transmission Fluid
     - Flush and Fill Antifreeze

Within in the last 4 months the transmission fluid was changed when I pulled the V-drive to replace the bellows on the P.S.S. shaft seal and the antifreeze was replaced (but not flushed) when the water pump (closed circuit system) started leaking.

October 23-24, 2004: Time to take wrench to the engine and see how things are going to go. 

Starting with the exhaust system I removed the exhaust riser and salt water injection point. The flange on the back of the exhaust manifold is made of steel with five bolts and is threaded for 1.5 inch tapered pipe threads. Due to the V-Drive installation the hot exhaust must rise approximately 18" straight up before turning back down to inject raw water and convert to wet exhaust hose. This system is made up of 1.5 inch galvanized pipe, the water injection point is a bronze nipple threaded into a 1.5 inch galvanized T. This system has worked quite well and held up well to salt water in the tropics, generally this system will last between 6 and 7 years before needing replaced. Bronze pipe lasts only slightly longer at significantly higher cost. The part list for a new exhaust system is:
     - 90 degree Street el (male to female)
     - 18" straight pipe (male to male)
     - 90 degree street el (male to female)
     - 90 degree (female to female)
     - close nipple (male to male)
     - 45 degree (female to female)
     - close nipple (male to male)
     - T for water injection with bronze 1.5 thread to 1" hose barb
     - 3" straight pipe (2" ID hose fits cleanly over 1.5 ID pipe)
     - 1 tube muffler repair paste for thread sealing
     - 1 muffler hanger to attach the highest point in the system to the cross bar to prevent vibration
     - 1 tube Permatex 1A for the pipe to hose conversion
The entire part list costs less than $40 at the local hardware store and automotive parts shop. The key to using this system is to keep an eye on the threads just upstream of the T used for water injection. Eventually this will show discoloration and if allowed to continue would probably eventually leak on top of the engine. A complete system can be stored in a single small container and can be easily made up with a couple of pipe wrenches. 

I then removed the exhaust manifold with it's exhaust leak between the manifold and the cylinder head. The forward (close to the transmission) flange seems to eventually exhibit this issue resulting in a small amount of exhaust gas in the engine room (when heavily loaded, i.e. significant backpressure) and a black oily substance around the flange and down the side of the engine. To remove the exhaust manifold it is easiest to either remove the header tank or cut the short piece of hose between the header tank and the exhaust manifold. While removing the nuts holding the exhaust manifold to the head I found that the forward most stud backed out with the nut, the hole for this stud is into the water jacket. The rest of the nuts came off of the studs normally. This same stud is the one which has seemed to be a bit loose when I would check the nuts on the exhaust manifold. With the exhaust manifold off the exhaust passage out of the head was exposed. While the exhaust manifold gasket was wet with a black oily substance the exhaust passage itself was completely dry with no deposits. This suggests that the issue may be with the stud which goes into the head leaking a small amount of antifreeze. I will replace this stud and use a sealant to ensure it does not leak. I will have the exhaust manifold checked for flatness at a local machine shop to ensure that the aluminum manifold has not become warped.

With the exhaust manifold removed pulling the header tank off the top of the engine for access to the thermostat was relatively easy. The joint between the header tank and the cylinder head has the thermostat and a paper gasket. There is a bolt on one side of the thermostat and a stud on the other side (for alignment). Both the stud and bolt go through holes in the aluminum castings. Care should be taken to clean the bolt and stud and applying a small amount of never seize to ensure that it won't freeze up. 

With the exhaust manifold removed the injectors and injector pump are easily serviced. As the injector pump was rebuilt in 1998 for the first time due to leaks caused by exposure to low sulfur fuel in California I won't rebuild the injector pump. The injectors were last rebuilt at the same time and are due for a checkup, the injectors are easily removed, break loose the connections at both the injector and the injector pump, remove the pipes and then the injectors. There is also a fuel return line running down the top of all of the injectors. This will also have to be removed, there is a copper washer above and below the connection point which has to be replaced when reinstalling the injectors. On a Perkins the injectors are pulled by removing one nut on either side of the injector and then wiggling the injector about it's axis while pulling up. I use a large adjustable wrench to grab the body of the injector (the part with the inlet fitting) and wiggle it back and forth while pulling up by hand. The injector should have a copper washer on the mounting flange, if it does not come out make sure to remove it from the injector bore. I checked each injector visually as I removed them. There was a fine jet black powder on the tip of each injector but no deposits and no oily material. The tips of the injectors are intact. They will be sent off to a local shop for pressure testing and verifying a good spray pattern. A bad spray pattern is the most likely cause of the soot on the back of the hull after motoring hard for several hours.

Next I removed the raw water heat exchanger to clean out the calcium deposits which form in the tubes which form the heat exchanger. I replaced the heat exchanger in 1995 due to corrosion causing the salt water inlet tube to fracture from the body of the heat exchanger. I have cleaned it out periodically with Meuratic Acid (pool acid) in 1998, 2000 (kwaj), and now in 1994. In each case none of the tubes were completely plugged, however, the exit of the tubes to the exhaust were significantly calcified. This is caused by the salt water temperature exceeding about 140F which cases the calcium to deposit on the walls of the tubes significantly restricting the ability to cool the engine. The indication that this was becoming an issue was a 5-10F increase in engine temperature under heavy load (2450 - 2650RPM). After removing the heat exchanger take the end plate off, drain completely and then SLOWLY pour the Meuratic Acid into the heat exchanger. Once full allow to sit for a couple of minutes (until it stops foaming), pour out the acid and repeat until no further bubbling is observed. Pour out the acid, rinse with water and pour in a mixture of baking soda (Sodium Bicarbonate) and water to neutralize the remaining acid. Reassemble the heat exchanger with a small amount of silicone sealant on the rubber gasket and end plate threads to prevent leaking salt water on the motor mount directly under the heat exchanger.

I purchased a spare starter motor for the trip back from Kwajalein to Los Angeles which I have not had to install. The original starter has a significant amount of corrosion due to it's proximity to the end plate of the raw water heat exchanger. With the rest of the equipment on this side of the engine removed this is an excellent opportunity to swap out the original starter motor with the spare. I will then clean up the original starter motor and keep it for a spare. As the bolts holding the starter have not ever been removed this is an excellent opportunity to apply some liquid wrench or other freeing agent.

Finally, the operation of the engine controls for both the throttle and the shift need to be reversed. The original Yacht Specialties controls were the opposite of what the new Edson controls need. 
 

Sunflower Photo Caption

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