SoCal Jet Boats

Tech Talk => Outboards => Topic started by: ron.h on February 21, 2017, 02:10:06 PM

Title: Starting problems with 15 horse Mercury
Post by: ron.h on February 21, 2017, 02:10:06 PM
I have a 1989 15 horse Mercury outboard when checking the timing with a timing light it shows about 60 degrees before top dead center when I try to start it pulls the Rope out of my hand I have good spark on both cylinders does anyone have any ideas and I can't get it to start if I pull it really hard and if at about 40 degrees before top dead center while it's running

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Title: Re: Starting problems with 15 horse Mercury
Post by: GT Jets on February 21, 2017, 02:54:38 PM
I have a 1989 15 horse Mercury outboard when checking the timing with a timing light it shows about 60 degrees before top dead center when I try to start it pulls the Rope out of my hand I have good spark on both cylinders does anyone have any ideas and I can't get it to start if I pull it really hard and if at about 40 degrees before top dead center while it's running

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Sounds almost like the flywheel key let go.

Check the compression and the flywheel key before proceeding.

Has it ever run since you owned it?

Should be able to fire it up with your bare hands on the flywheel.... Seriously.

GT

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Title: Re: Starting problems with 15 horse Mercury
Post by: ron.h on February 21, 2017, 04:10:25 PM
I can get it to start when it's running it's at about 40 degrees before top dead center at an idle it's just extremely hard

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Title: Re: Starting problems with 15 horse Mercury
Post by: GT Jets on February 21, 2017, 04:44:55 PM
I can get it to start when it's running it's at about 40 degrees before top dead center at an idle it's just extremely hard

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Did you have it apart?

What's the model number?

GT

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Title: Re: Starting problems with 15 horse Mercury
Post by: ron.h on February 21, 2017, 04:47:21 PM
0g23385

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Title: Re: Starting problems with 15 horse Mercury
Post by: ron.h on February 21, 2017, 04:49:46 PM
No I do not have it apart

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Title: Re: Starting problems with 15 horse Mercury
Post by: Lopes on February 21, 2017, 05:50:08 PM
I know this sounds stupid but are you sure it not in gear?


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Title: Re: Starting problems with 15 horse Mercury
Post by: GT Jets on February 21, 2017, 07:07:27 PM
Do you have a picture of the flywheel? Do you know what marks to use?

The timing at throttle pick up should be extremely retarded, like 10° ATDC....
The wide open timing should be about 25°BTDC, I will be home soon and will grab a book.

Meanwhile, pull the flywheel nut and see if the key slot lines up.

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Title: Re: Starting problems with 15 horse Mercury
Post by: GT Jets on February 21, 2017, 09:12:16 PM
So thinking about this over a bourbon and Coke, if the key is good, put a CDI box on it.

Good hunting.

GT

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Title: Re: Starting problems with 15 horse Mercury
Post by: ron.h on February 22, 2017, 03:52:43 AM
From what I have read the CD box actually change the timing is that correct

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Title: Re: Starting problems with 15 horse Mercury
Post by: ron.h on February 22, 2017, 03:52:57 AM
I will take pictures of the flywheel tonight

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Title: Re: Starting problems with 15 horse Mercury
Post by: ron.h on February 24, 2017, 07:02:42 PM
I want to thank everybody for their help it was the switch box motor runs great thank you

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Title: Re: Starting problems with 15 horse Mercury
Post by: GT Jets on February 24, 2017, 07:33:02 PM
I want to thank everybody for their help it was the switch box motor runs great thank you

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Score...

Happy motoring.

GT

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