Merc 40 No Start

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serialnb

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May 15, 2005
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I aquired this motor after it sat for 3 years. Changed the spark plugs and proceeded to try to start it. Spins, but won't "catch" and fire. Spark is present on atleast the top cylinder, when the primer bulb is pressed too hard, you can get a squirt of gas to come out of an opening at the top left of the carb (if facing head on). Figured I would see what ya'll could help with before I tear into it too far.<br /><br />Edit : 1998 Mercury 40 2 cycle (rebadged tracker)
 
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Laddies

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12,218
Re: Merc 40 No Start

The little squirt of fuel is normal as long as it don't just continue to leak, have you tryed to prime the engine with a little fuel in a squirt can thru the carb, to see if the problem is fuel or spark, ck the plugs to see if their wet, you need to find out if the problem is spark or fuel related--Bob
 
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serialnb

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Re: Merc 40 No Start

When I pulled the plugs they were not wet. Will try spraying fuel into the carb tomorrow, thanks for reminding of that small troubleshooting procedure :D . I think smacking my head against the motor did neither of us any good.
 
JB

JB

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45,907
Re: Merc 40 No Start

Howdy, SN.<br /><br />Welcome to iboats. :) <br /><br />Go to the Engine FAQs and check out troubleshooting for "Outboard wont start".<br /><br />Good luck, and let us know what you find. :)
 
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serialnb

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Re: Merc 40 No Start

When a spray of fuel is introduced down the carb she tries to run. I'm gonna run and get a fuel filter (my buest guess, and extra insurance), any other ideas? I appreciate all help and would like to offer a thank you in advance.
 
Silvertip

Silvertip

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Sep 22, 2003
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28,771
Re: Merc 40 No Start

You have a fuel delivery problem and it is very unlikely its the fuel filter (although it doesn't hurt to change it anyway). The carbs are probably the culprit and are clogged with gum and varnish from sitting. They need to be removed, disassembled, every passage thoroughly cleaned and blown out with compressed air and then assembled with new kits. You might also consider rebuilding the fuel pump at the same time. Set float level and make adjustments per the service manual. In the future, use a fuel conditioner (SeaFoam or equivalent) to keep the system clean and condition the fuel.
 
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serialnb

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May 15, 2005
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Re: Merc 40 No Start

Yeah I figured the fuel filter was a long shot, but had to try anyway :) While replacing that I found a fuel line that had a hole in it, coming off the bottom of the fuel bowl. Now she will kick and try to run for 3-5 seconds. EDIT : Actually got her to start and run 1-2 minutes, but now all I can get is 10-20 second running bursts, so the carb needs to be cleaned? How difficult is one of these carbs to take apart? EDIT 2 : As long as the choke is held in, she'll idle.
 
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serialnb

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May 15, 2005
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Re: Merc 40 No Start

Update, took the carb off, cleaned it out, reassembled. Now I get a steady run, but at 3k-4k rpm.
 
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Laddies

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Re: Merc 40 No Start

You must have got part of the problem fixed, did you clean tha high speed with a ip cleaner or something it sounds like it still could be the problem
 
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serialnb

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Messages
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Re: Merc 40 No Start

Laddies and upinsmoke thanks for the help, I finally was able to sit and visualize how things worked (only took part of a 6 pack). Took everything down again, replaced the rest of the fuel lines for good measure, reset the carb and the one linkage I disturbed routing fuel line. She starts fine and idles great. I love the smell of burning 2 cyl mix :) Now to get the thing to the actual lake......
 
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