1997 C40MLA 2 stroke 4 cylinder primer system?

oregonducker

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Feb 10, 2004
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Manual start with the little primer bulb for the carbs. The bulb won't pull gas up far enough to then send it back down to the carbs. The pickup tube sits about 2/3 full and when you depress the primer bulb it pushes all the gas back into the upper carb but when you let it go it only goes back to 2/3 full in that tube. Should it be sending the all the fuel back to the upper carb? Do I need a new bulb?
 

oregonducker

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Serial Number 0G449063

I've been trying to pull up the parts list/diagram on the Mercury parts site but haven't been able to find my particular motor/carb setup.
 

racerone

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Dec 28, 2013
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I found those primer components in about 30 seconds for that serial #-----Do you understand what this little primer bulb does ??-----What is your motor doing / not doing ?
 

oregonducker

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The primer bulb doesn't move gas to the carbs when you need it to for a cold start. When you push it the gas in the tube just goes back into the upper carbs bowl and when you release it the same amount comes back up the tube but never goes far enough to make it to the carbs for priming. The rest of the motor is fine.

It seems like there should be a check valve type of thing at the upper carb bowl so gas can only come out and not back in as you pump it. I don't know which is why I was looking for the parts diagram. When I enter the serial number I get the 40 hp 4 cylinder but the carburetor pics and parts don't match my motor. When I try to view the supersession list I get nothing.
 

oregonducker

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How about this? Is the "check valve" or whatever it might be called in the bulb like it is in gas tank primer bulb?
 

racerone

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I can find the parts pictures with no issue.----Sounds like a bad check valve or dirt in the check valve.----Remove bulb from motor and try to flush it.-----Where are you looking for the parts ??
 

oregonducker

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Mercury Parts Catalog The pics I get of the carbs show a cover plate (part #22). Mine doesn't have that part just a plain hose barb on the side in place of the cover plate. That's just one example of a difference.
 
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racerone

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I see a new primer bulb for $82.75 and Sierra for $33.11.----This is for the primer for starting.----Not the primer bulb on the hose for filling the carburetor.
 

oregonducker

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Feb 10, 2004
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Well I took the little primer bulb off and managed to get some carb cleaner into the little holes. Let that sit for an hour and then it was able to pull solvent into itself from a little cup so I put it back on and now it's sending fuel where it's supposed to go. It fired on the first pull and started on the fifth at 40 degrees. Just what I needed. Thanks for the help!
 
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