Perkins 4.236 Engine Repair: Water in Oil


A few weeks ago before Hurricane Florence hit New Bern, we had a problem starting our Perkins 4.236 Engine.  The starter would barely turn over and then stop.  I’m learning, but I am not a good engine guy yet, but I am slowly learning how to do some basic Perkins 4.236 Engine Repair myself.  We had a friend look at it and they noticed that we had more oil on the dipstick than usual.  A LOT more.

A couple of people looked at it and the proposal was given that we had diesel in our oil.  The proposal was based on there being more oil than usual and the possible hydro-lock we experienced when turning over the starter.  I kept noticing that I didn’t smell diesel when I would check the dipstick, but figured maybe the scent had dissipated in the diluted oil.  The likely suspects for diesel in the oil are:

  1. Leaking fuel injectors (relatively cheap to fix at $109 per injector)
  2. Lift pump gasket (relatively cheap to fix at $200 for a new pump and gaskets)
  3. Problem in the fuel injector pump (relatively expensive at $2000+ to replace)
Seeking Help

Today we had Chuck Courtney from Power and Sail Boat Mobile Repair come look at the engine.  See below for important disclosure information regarding the edit of our original post regarding this experience.


2019 JUN 13:
Although we despise saying things that are negative about anyone, we feel it necessary to point out to our readers that it is our full belief that all corrosion damage and subsequent full engine rebuild was a direct result of being instructed to over-crank the engine with the sea-cock open by this technician.

I feel the need to provide some information here for our readers that was not fully understood and went unnoticed at the time of the original post.  During Chuck’s initial visit, he instructed us to over-crank the engine and intentionally prevent the engine from starting.  He made a dismissive comment regarding closing the sea-cock and instructed me to proceed.  At the time, I had no idea what the ramifications would be in not closing the sea-cock due to unfamiliarity with the details of our engine seawater exhaust system.  I then proceeded to over-crank the engine multiple times as instructed in order to allow him to check something involving the starter. 

In our Perkins engine, anytime the cylinders are moving, the raw water pump is drawing in water.  In order to remove the water, the engine has to overcome the pressure of the water-lock, which “spits” that seawater out the back of the boat.  By continually cranking the engine without starting, the drawn in water has no place to go except into the exhaust hoses until it eventually back-fills directly into the cylinders.

It was later determined by our repair facility that the cause of the rising oil level and the hard starting was due to a failed diesel lift pump (a $100 part).  The cause of the flooded engine was due to “over-cranking the engine with the sea-cock open.”

The end result to us was over $25K worth of repairs taking over 8 months to complete which, to date, have all been out-of-pocket.

If you lack the knowledge of how your boat engine system operates, take some time to learn how your particular system works PRIOR to allowing ANYONE to do anything on your engine that you do not fully understand.  Failure to do so can be disastrous… and expensive. 

We do not include this to speak ill of this technician or anyone or for any other purpose than to caution boat owners to be careful.  People make mistakes but sometimes seemingly trivial actions have disastrous consequences.  PLEASE make sure your technicians are certified or experienced in your specific engine prior to allowing them to work on your boat.

I was immediately impressed with his attention to detail.  He also seemed to really want to educate his customers in what to look for when diagnosing engine problems.  As aspiring cruisers, we love when experts help us learn because it gives us experience and encouragement in doing more Perkins 4.236 Engine Repair projects ourselves.

Yesterday, we ran Banjo for an hour or so in order to prepare for Hurricane Michael.  It took a couple of tries to get her started.  Once started, she didn’t overheat or seem to struggle.  Today, we tried to start the motor and she would not start.  At one point we saw a small amount of smoke coming from the starter motor. 

Additional EDIT:

2019Jun13: For clarification, the smoke witnessed from the starter occurred when we were instructed to over-crank the engine.  We later learned that over-cranking is DISCOURAGED by nearly all mechanics and engine manufacturers.  Starters are designed to be used, at MAX, NO LONGER than 2 attempts for 15 seconds each.  After those 2 attempts, the starter requires a cool-down period of several minutes before trying again.  In our case, we were instructed to over-crank, back-to-back, 7-10 times, which eventually burned out our starter destroying it and requiring it to be rebuilt. 

Chuck pulled a sample from the crankcase and immediately stated that it looked like we had water in our oil, not diesel.  What a complete surprise!!

Perkins 4.236 Engine Repair: Water in oil Perkins 4.236 Engine Repair: Water in Oil
Getting Together a Plan to Move Forward

In order to perform the Perkins 4.236 Engine repair, we needed to address a couple different problems.  First, our starter motor needs to be disassembled and rebuilt.  Chuck recommended unbolting the motor from the engine and taking it to Squires Automotive Auto Generator and Starter Service in Kinston, NC.  They would be able to, according to Chuck, rebuild the starter motor in a few hours and were reasonably priced.  Second, he stated that the most likely cause for water in oil was a blown head gasket.  Third, he recommended that we not run the engine again until we have changed the oil.  His suspicion was that the engine would not start due to the oil being too diluted to allow proper lubrication.

This problem is much more involved.  The replacement of the head gasket is not terribly difficult once it is exposed.  The problem comes in getting to it.  In order to gain access, there are several other systems that have to be disassembled.  Chuck recommended us getting a second opinion before undertaking the work and expense of replacing the head gasket.

So, not such great news today.  He did state that overall our engine appears to be in great shape.  So it looks like we are in for some serious work on this Perkins 4.236 Engine repair.  On the upside, Chuck taught me how to bleed the fuel system of air, discovered that we have an oil drain hose, and showed me how to change the engine fuel filter.  Knowing is half the battle.


Follow our other posts on Perkins 4.236 Engine Repairs and other boat repair and maintenance projects.

Related posts

Leave a Comment

thirteen + 1 =

This site uses Akismet to reduce spam. Learn how your comment data is processed.