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takeahiketour

Mercruiser 350 Mag MPI Drain Plugs

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Accidentally fired up the boat without replacing the drain plugs from winterization. Ran for about 30 seconds. Any concerns that this could have damaged anything? On the plus side, I now know my bilge pump is working great! Also, looks like there are four blue screw-in plugs, petcocks I believe they're called (that's what I found in the glovebox). Anyone know the locations to replace them? One was obvious and I have it back in already but then the twist top snapped off right when I got it in! So also looking for a part number to get new ones if anyone has it....

In summary three questions - 1. possible damage from starting without drain plugs. 2. Drainplug location. 3. Drainplug part #. The boat is 2005 but I believe the engine is 2010 approximately, I don't have the serial number handy.

Thanks everyone!

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Doesn't take very long for the bilge to get full with water with the plugs out and engine running; I think you'll be just fine for only 30 seconds run time.

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20 minutes ago, takeahiketour said:

Accidentally fired up the boat without replacing the drain plugs from winterization. Ran for about 30 seconds. Any concerns that this could have damaged anything? On the plus side, I now know my bilge pump is working great! Also, looks like there are four blue screw-in plugs, petcocks I believe they're called (that's what I found in the glovebox). Anyone know the locations to replace them? One was obvious and I have it back in already but then the twist top snapped off right when I got it in! So also looking for a part number to get new ones if anyone has it....

In summary three questions - 1. possible damage from starting without drain plugs. 2. Drainplug location. 3. Drainplug part #. The boat is 2005 but I believe the engine is 2010 approximately, I don't have the serial number handy.

Thanks everyone!

Hmm, if you have a Bravo drive, then I would say:

1 in thermostat housing on top of engine

1 in water distribution drain housing low down front PORT side of engine 

2 for seawater pump low down on STBD side of the engine

maybe 1 for cool fuel module above seawater pump on STBD side of the engine

Mercury part # 806606A02 superseded to 8M0119211

 

Image result for mercruiser blue drain plugs

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Just now, Shepherd1 said:

Hmm, if you have a Bravo drive, then I would say:

1 in thermostat housing on top of engine

1 in water distribution drain housing low down front PORT side of engine 

2 for seawater pump low down on STBD side of the engine

maybe 1 for cool fuel module above seawater pump on STBD side of the engine

Mercury part # 806606A02 superseded to 8M0119211

Image result for mercruiser blue drain plugs

That is definitely the part, thanks! The drive is an Alpha One Gen 2 Model # 5121300LS.

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Just now, takeahiketour said:

That is definitely the part, thanks! The drive is an Alpha One Gen 2 Model # 5121300LS.

Okay, fuel injected or carb engine?

 

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9 minutes ago, takeahiketour said:

It's Fuel injected. Here's a photo. Thanks!

IMG_3123.JPG

Okay, I think you have the standard 7 point drain system for your 350 Mag MPI Alpha 1. Please see 4 of # 16 in the picture below.

2 for exhaust, 1 for large hose from thermostat housing to engine circulating water pump, and by low down by fuel cooler on PORT side of engine.

http://www.marinepartsplus.com/catalog/mercruiser/serial/6.2L_MX_MPI_BRAVO/884717003/12840-210

NOTE: should this be your set up, recommend giving the check valve # 13 a tap with gear driver after draining the engine in the fall to ensure no water is trapped. 

10134.GIF

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Final update - there turned out to be six drain plugs. Four as shown in the diagram, but not the fifth one in the diagram between the two spark plugs. Then two more mid-block. Wasn't able to find the last two except by running it and seeing where the water came out. Once found, they were all pretty easy to access and get the plugs in. Engine is labeled as model "MCM 350 MAG MPI." 8M0119211 is the correct part # for the plugs.

Also, running for under a minute without the blue drain plugs in did not do any damage. However, had the bilge pump not been working properly it quickly could have.

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On 3/30/2018 at 1:07 PM, takeahiketour said:

Final update - there turned out to be six drain plugs.

Glad you got it figured out. Forgot to mention, but if each o-ring isn't in place, water will drip from the plugs when the engine is running.

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