Pressure Test The Block?

So the next step is I’m going to have to pressure test the block somehow! This is an open loop cooling system, so there is no easy way pressurize the cooling system. My Sea Doo’s are closed loop. Just put my radiator pressure tester on the coolant recovery tank. Pressurize it to 15 pounds and see if it bleeds off pressure. There is a version of this engine that is closed loop with a heat exchanger, but that is not mine. I’m working backwards here because there is water in the oil and no indication of where it came from. The intake or the weather jacket in the am heads could be cracked in the lifter valley and dropping sea water into the valley. I may also use my bore a scope and see what I see in the intake. This is a thousand dollar part as I said , but its less time consuming than pulling the entire engine.

So off to the store to get a 2″ rubber cap and 1″ PVC Pipe. This whole endeavor may be a waste of time, but the idea is to see if the cooling system will pressure up. If it does, there is not a crack in the block and I have another mystery to solve. Update of 12/16/20.

Update 12/17/20, it’s not 1″ and 2″. Its 3/4 and 1.5 Inch rubber cap. Will have to go back to the store for caps and PVC caps. This is a thirty mile round trip! So the old adage of measure once, cut twice is really measure once, make two trips to the store!

So, 3/4 PVC, two caps, a threaded end piece with a threaded cap, and a 1/2 inch rubber cap. I plan on attaching a fitting to the cap so I can either use shop air or the pump from the radiator pressure tester. I replaced the thermostat housing gasket. I will have to put that back on. The gasket looked like it came with the boat and was leaking. The intake is just had rust from end to end.

Thermostat housing removed
This is sort of what the cooling system looks like.

This is sort of what the cooling system looks like. Going to block off all the outlets to the thermostat housing. That should be 2x 3/4 inch PVC pipe and the large 1.5 inch opening. That’s going to have to wait for the weekend.

I have to drop off this boat on Saturday that I repaired the wiring harness in. The wiring harness on the starboard engine was melted in places. There is not a wiring harness available. The owner hooked the battery polarity in reverse. Luckily it did not fry the electronics like the ECU. Apparently lots of folks hook up batteries backwards. Again, they built the boat around the engines and electrical harness. I think I’m going to find this a common theme. Luckily I’m flexible to maneuver into tight spaces.

Remove parts to access intake (Intermediate Step)

Need to get access to the intake and Exhaust Manifolds. This is the second person who has told me to inspect the lifter valley (Jimmy and Steve). Jimmy is the knowledgeable on Jet Skis and Steve is the person that does all my engine work back in Memphis.

  • Remove Neutral Safety Switch & Related Electrical Connections
  • Remove Throttle Cable & Disconnect Fuel Injectors
  • Remove the plate that holds the relays

I can’t drop off the Yamaha boat it’s raining and I need parts from jimmy to seal up the electrical boxes. When I spoke Jimmy today he suggested that there is likely a cracked head or the in lifter valley with that much water in the the oil. So I’m still going to pressure test the block. He also gave me a suggestion of local contact for parts for Mercruiser. I’ve removed the neutral safety switch, throttle cable, plate the holds the relays, spark plug wires for the even cylinders. I removed the bolts, nuts and screws then put them back in the place where I removed them from. I’m also going to have to get a heater of some sorts. It’s too cold for me to work! That’s the update for 12/19/20.

Not much progress here with christamss and the related activites that occured. I had to spend some time putting that the pay boat boat back togeter . It took quite sometime and and I needed a second set up hands. Luckily my youngest son helped tremendously. I Dropped it off yesteraday afternoon. We also spent time getting some tools storage for the new garage. I spen most of Saturaday getting that and putting it togeter. I should only need one more peice to complete that. As a result of finishing the pay boat I’ve recoved some space for other projets or storage. That’s the delima with space, do you leave it free or fill it up ?

I Still need to get the Intake off. This is going to require me to get the motor to Top Dead Center on cylinder #1. Going to verify this using a technique that does not involve the pointer and mark on the crankshaft pully. this is the update for 12/28/20.

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