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Couple Quick Questions - re 7.4L...

Den
Guest Contributor

Couple Quick Questions - re 7.4L Merc MPI Engine Gen VI on a 2001 Sea Ray 280 SS/Bravo III Drive:

 

1-What is the correct Torx size drive necessary to remove the plastic covers on top of the engine to expose the flash arrestor?

2-Found the "Quick Drain Oil Tube" laying in back of bilge area (supposed to be connected to the stern drain plug). Anybody use this feature and is it worth trying to connected it back up to drain plug tether so I can fish it out the drain plug opening when I do an oil change?

3-Anybody use full synthetic or a synthetic blend oil in this engine? Any pros or cons?

4-What's a good nationally branded substitute for the overpriced Merc 25-40 oil recommended by Mercruiser?

5-Any recommendations on nationally branded outdrive lube other than the Merc Recommended SAE 90W?

6-Any pros or cons using a synthetic blend or full synthetic vs a standard SAE 75-90W or 85-90W lube in the Bravo III outdrive?

7-Re fogging engine ....I understand that since there are fuel injectors and no carburetor on this engine that the best way to protect the engine interior is to pour off some gas from the existing fuel -water separator, replace it with the same amount of 2-cycle oil, reinstall the filter and run the engine until it sputters & chokes then shut it off and replace the fuel -water separator with a new one ....Any comments or suggestions?

 

Thanks for any and all input...Dennis (Buffalo, NY)

11 REPLIES 11

wingless
Rising Contributor
Get a full set of Torx driver bits. They are used in many applications. Every one of my tool sets has a full set of Torx drivers. The intake plenum on my 454 Magnum Horizon engines is retained by fasteners w/ T-40 female receptacles.

My engines originally used the Mercruiser oil. Now they use the Mercruiser synthetic oil.

The FSM says to fog the engine. I fogged the engines. I also didn't see the benefit.

My FSM says to pour engine oil into the fuel filter. It will NEVER sputter and choke off because of oil in the fuel. The engine will run w/ a fuel / oil mixture all day long. The ONLY way to get the engine to sputter and die is to kill the fuel source.

The factory used three Parker Skinner valves, P/N V5C72120, on my boat, one for each engine and one for the generator. These valves have a manual twist control and an electrical control, to pass fuel or to shut off fuel.

The 1/2 turn twist knob is labeled "OFF" and "ON". The valve should ALWAYS be left on the "OFF" position. The function of the valve in the "OFF" position is that the flow is controlled by the electrical connection. When the knob is rotated to "ON" it is always on.

So.... to shut off fuel for winterizing, remove one wire from the Parker Skinner valve. Then start the engine w/ the fuel / oil in the fuel filter and idle the engine 'till it starts to die. Wait w/ the fogging to shoot it into the intake at the last gasp.

FWIW, the intake plenum should be removed and fully cleaned at least once per year. It is a poor design and the ONLY way to ensure proper operation is to maintain it as very clean. Pay special attention to the small ID vacuum hose feeding down to the fuel pressure regulator. Remove, clean, dry and reinstall that hose at least annually. If it has oil then also flush out the vacuum hose barb on the fuel pressure regulator.

http://i101.photobucket.com/albums/m52/wingless-pics/Boat/OilChangeFuelCutoffFireExtinguisher.jpg

Den
Guest Contributor
Thank you ....but I don't have the set up of valves you have to control fuel etc.

wingless
Rising Contributor
Where are the fuel shutoff valves for your engine?

What type of shutoff valves are used?

Den
Guest Contributor
I don't have any fuel shut off valves to the best of my knowledge.

wingless
Rising Contributor
The shutoff valve is a USCG requirement. Follow the fuel hose from the tank to the filter to locate the valve.

As was stated, shutting off the valve is the only way to have the engine sputter then stall during winterization.

Den
Guest Contributor
OK will do ......Any thoughts regarding my other questions regarding oil and stern drive lube? Questions 2, 3, 4, 5 & 6

wingless
Rising Contributor
My boat is vee drive, not stern drive, so I have no comment on your stern drive questions. My linked image also shows my custom high-volume high-pressure five-zone oil change change system.

As stated I use the "overpriced" Mercruiser synthetic in my engines.

Peteatthebeach
Guest Contributor
It is so easy to drain the oil with the tube that is pulled out thru the drain plug. Use a plumbers snake or electrical cable pulled to fish the tube out.
Keep using the merc oils, the synthetic blend 25/40 saved my engine I feel when my oil cooler leaked raw water into the oil.

Peteatthebeach
Guest Contributor
Attach the tube to the drain plug (it should have a hole drilled in the plug) with about 2ft of fishing line.

Den
Guest Contributor
thanks ...that worked! Much appreciated

Acon
Guest Contributor
I never use the drain hose. I vacuum out the oil. Much cleaner for me. I don't want to climb in and out of my engine room more than I have to. Though I have twins in a 290 sundancer. Less room.