A few quick Merc 3.0 Questions

Mscanon99

Petty Officer 2nd Class
Joined
Sep 10, 2007
Messages
122
Hi All,

Thanks for all the help in the past, I now have a 1997 Starcraft with a Merc 3.0/Alpha One.

This is my first I/O, I always had OB boats in the past.

When I ran the boat on the muffs, I expected the water to come out the prop, however most of the water came out of an area below where the outdrive is attached to the transom. I thought that was odd. It must have a discharge in this section, again, under the section where it is attached to the transom.

Second, I was checking over the motor and thinking about changing the plugs, when looking at the head of the motor (I think this is the right term), where the plugs are installed, this section of the motor is very rusty while the rest of the motor is a clean, black and shiney. My thought was that I should blow the plugs off before removing them to make sure nothing falls into the cylinders. Is the rust on this section of the motor normal?

Any feedback would be much appreacited. I did buy the boat from a dealer and they changed the oil motor and outdrive oil and did the general service.

Thanks

MS
 

1980Galaxy

Petty Officer 1st Class
Joined
Apr 11, 2009
Messages
339
Re: A few quick Merc 3.0 Questions

i would take some compressed air and blow away the loose debris from around the plugs BEFORE removing them and be careful not to get anything down the holes. dunno why its rusted on that side, maybe water is getting on that side from some unknown source? i dunno... a pic would help a little bit.
 

JustJason

Vice Admiral
Joined
Aug 27, 2007
Messages
5,319
Re: A few quick Merc 3.0 Questions

Yes if you have scaling blow it off with some compressed air. As far as why its rusting thats up to you to figure out. Could be a water leak in the compartment somplace, which should be easy enough to find. Or it could be just some spray finding its way under the cover. Clean it up the best you can and just shoot it with some rustoleum.
As far as the water exhaust. There are some idle relief ports on the outer transom plate, and its normal. It wouldn't hurt though to tilt the drive all the way up and have a looksee at the exhaust bellows for leaks.
 

Mscanon99

Petty Officer 2nd Class
Joined
Sep 10, 2007
Messages
122
Re: A few quick Merc 3.0 Questions (cant load pics)

Re: A few quick Merc 3.0 Questions (cant load pics)

Hi, Iboats will not let me upload the pics becuase of file size, any advice?

My main concern is why is this section of the motor rusty, while the rest is all black paint? The section I am speaking of is below the valve cover, I am guessing it is the head. This is where the spark plugs go in the motor.

Just Jason, thanks for the note on the exhaust. When running in the water, does the water still come out this section or through the prop?

Thanks to all,

Mike
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,506
Re: A few quick Merc 3.0 Questions (cant load pics)

Re: A few quick Merc 3.0 Questions (cant load pics)

Iboats will not let me upload the pics becuase of file size, any advice?

Ayuh,... Resize 'em to 480x640,... or post a link to them...

I am guessing it is the head.

Yes it is,... It's been replaced or rebuilt at sometime past...

does the water still come out this section or through the prop?

Ayuh,... The path of least resistence...
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: A few quick Merc 3.0 Questions (cant load pics)

Re: A few quick Merc 3.0 Questions (cant load pics)

Hi, Iboats will not let me upload the pics becuase of file size, any
advice?

Have a look at the top 3 stickies in the link below.
http://forums.iboats.com/forumdisplay.php?f=32


Just Jason, thanks for the note on the exhaust. When running in the water, does the water still come out this section or through the prop?

I'm not Jason, but exhaust will come out those holes at idle because there is less back pressure there at idls and it keeps the boat from stalling.
At higher speeds, the prop is actually pulling the exhaust thru the prop. There might be some exhaust out the idle reliefs,but it's not a big deal.


My main concern is why is this section of the motor rusty, while the rest is all black paint? The section I am speaking of is below the valve cover, I am guessing it is the head. This is where the spark plugs go in the motor

You have to figure that out, we can't see your boat, even with pics. Run the engine look for leaks, and use the hose on the engine cover with the engine off and see if it gets wet.
 
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