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Merc 502 spitting oil

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Old 12-12-2004, 08:09 AM
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Default Merc 502 spitting oil

I Finnaly moved from Cruisers to a performance boat. I took my new to me 312 Formula out yesterday for a test run. Everything on the gauges looked fine all day even at several WOT stretches. When we returned the front part of the motors had dropped a small amount of oil into the bilge. How concerned should I be about this? I have heard the 502's burn oil, but didn't think they spit it out. These motors are 98 models, look clean (whatever that's worth), and have 380 hrs.
I guess I'll need to post some pics of a new members boat sometime too!
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Old 12-12-2004, 09:03 AM
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Thumbs up Re: Merc 502 spitting oil

It's good to hear that you finally got it home!!!!

If it's just a small amount, it's possible that it's coming out of your trim pumps. Get some leak-proof caps from turbosonic.
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Old 12-12-2004, 09:12 AM
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Default Re: Merc 502 spitting oil

Both engines had the same oil leak? Did any of the belts or pulleys whip the oil around to the underside of the engine hatch?
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Old 12-12-2004, 09:50 AM
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Default Re: Merc 502 spitting oil

Gotta know where its coming from. Might be a big deal. Might not.
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Old 12-12-2004, 10:37 AM
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Default Re: Merc 502 spitting oil

Thanks guys!
When I got home last night it was dark, I'll go dig around now and be back in a little while.
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Old 12-12-2004, 11:13 AM
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Default Re: Merc 502 spitting oil

ok....I see where the oil is coming from. It's the same from both motors. It appears to be the front seal behind the timing belt? The lower center pulley that has the timing marks on the disk behind it right?[IMG]http://[/IMG]
I'm attepting to attach the photos of the motors, hopefully they help.
Thanks again.
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Old 12-12-2004, 03:54 PM
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Default Re: Merc 502 spitting oil

I am trying to figure out what kind of oil leak at the front of the engine could be a big deal. Should be either timing cover seal, oil pan seal or front intake seal. Maybe I missed something... Please enlighten.

BT
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Old 12-12-2004, 04:06 PM
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Default Re: Merc 502 spitting oil

Front crank snout seal isn't a big deal (there's no timing belt, it uses a chain unless it has a massivley expensive aftermarket Jesel drive). It's a little odd, though, that they're leaking unless the motors have been into a few times (without new seals each time).

Easy to replace.
It MAY however, be an indicator of a worn front main bearing due to possibly having had a previously installed supercharger on the motor before you bought it. If that is the case, you could have some other issues as well.
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Old 12-12-2004, 05:05 PM
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Default Re: Merc 502 spitting oil

For some reason I don't think anything aftermarket has been done to these motors. Sorry about the timing belt comment... I meant chain. I am a novice though obviously. I just dropped the thing off with my mechanic to check out a number of things, this just got added to the list.
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Old 12-12-2004, 07:11 PM
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Default Re: Merc 502 spitting oil

testing downloading photos.....These were supposed to be in an earlier message.
[/IMG]
[IMG]
If there are no photos here, what am I doing wrong?
Attached Thumbnails Merc 502 spitting oil-port-engine.jpg   Merc 502 spitting oil-starboard-engine.jpg  
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