Daleo56
Member
7.4L MAG MPI Horizon Gas Engines / Starboard rebuilt with previous owner in 2015
1998 Sea Ray 370 Aft Cabin
I was out on the ocean yesterday at about 3,000 rpms and heard a loud bang on the starboard engine followed by ticking. I shut down the engine and went into the engine compartment and saw the noise was from the #1 cylinder missing the spark plug insulator. The plug wire was dangling and the insulator was nowhere to be found. We limped back to the marina on one engine and I then found the insulator (shown below) at the rear of the engine compartment. I used a bore-scope to look inside the cylinder this morning. The picture is the second one below from the #1 cylinder looking through the spark plug hole.
I had changed the plugs a few months ago and only had a few hours on the engines since then.
TWO QUESTIONS
PART ONE: With the new spark plug installed the engine started and ran for a minute before dying. I noticed water (not antifreeze) coming from the PCV hose connection (the valve cover PCV) and when I removed the PCV hose a pint of water came out. Fortunately it was not making it to the valve cover because of the one way PCV and there is NO water in the oil. There was water in the plenum based on the routing of the PCV hose though! I then left the PCV hose disconnected. I let the engine sit for a few minutes and started it back up. After about 60 seconds of the running the engine died again and then another pint of water came out of the now disconnected PCV hose. I assume since the hose was spitting out water that the plenum had a lot of water and it. Since the second attempt was new water, I gave up and figure I must have a stuck open intake valve in #1. Before I start pulling the engine apart I was hoping someone had seen this before and could offer some advice.
PART TWO: Does anyone know what the round metal thing (pictured below) on the left side of the inside head? Could that be the intake valve smashed against the valve seat, shattered and deformed?
NOTE: The slight rust is because we got back late and I did not take the picture until this morning.
1998 Sea Ray 370 Aft Cabin
I was out on the ocean yesterday at about 3,000 rpms and heard a loud bang on the starboard engine followed by ticking. I shut down the engine and went into the engine compartment and saw the noise was from the #1 cylinder missing the spark plug insulator. The plug wire was dangling and the insulator was nowhere to be found. We limped back to the marina on one engine and I then found the insulator (shown below) at the rear of the engine compartment. I used a bore-scope to look inside the cylinder this morning. The picture is the second one below from the #1 cylinder looking through the spark plug hole.
I had changed the plugs a few months ago and only had a few hours on the engines since then.
TWO QUESTIONS
PART ONE: With the new spark plug installed the engine started and ran for a minute before dying. I noticed water (not antifreeze) coming from the PCV hose connection (the valve cover PCV) and when I removed the PCV hose a pint of water came out. Fortunately it was not making it to the valve cover because of the one way PCV and there is NO water in the oil. There was water in the plenum based on the routing of the PCV hose though! I then left the PCV hose disconnected. I let the engine sit for a few minutes and started it back up. After about 60 seconds of the running the engine died again and then another pint of water came out of the now disconnected PCV hose. I assume since the hose was spitting out water that the plenum had a lot of water and it. Since the second attempt was new water, I gave up and figure I must have a stuck open intake valve in #1. Before I start pulling the engine apart I was hoping someone had seen this before and could offer some advice.
PART TWO: Does anyone know what the round metal thing (pictured below) on the left side of the inside head? Could that be the intake valve smashed against the valve seat, shattered and deformed?
NOTE: The slight rust is because we got back late and I did not take the picture until this morning.
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