have an older 9.9hp mercury. problem is family ran it few years back, and i think i remember them running it on straight gas before i asked if they mixed it 50:1. but i know it ran for a while after that, like the rest of the summer no problem. then it had idle problems and would only run if you pulled the starter cord with it in gear at half throttle, and you could run it at maybe 33% to full throttle and it run move the little boat fine. but would die when coming down to idle. figured it was typical carb problem.
motor sat for last 4 or so years. shortly after taking ownership, i tried fixing the idle problem: cleaned carb and put a new carb kit on it, did not fix. also put new ignition box in it. best of my knowledge it never had a spark problem. after that i came to the conclusion i needed a new carb because the original one has a thin idle tube that comes up through the middle of it to the idle well on top where the idle mixture jet is. i tried manually putting a vacuum on that on the bench and it would not pull fuel. nor when i had it running i would shut it down and pull the cover off the idle well on top and it would be dry.
got around to buying new carb and tried starting it tonight but no luck. only thing different is i bought the 15hp carb which fits the motor fine and it was also cheaper. as far as i know the only difference between the 9.9 and 15 outboards is the carb and everything carb-wise is the same except the round throat on the reed block side is larger by a few millimeters.
motor fires once pulling the cord which puts the pistons through maybe 4-5 strokes but will not run. i've checked spark on each plug and it is strong. i've checked timing on the flywheel with a light and it's within range. i've sprayed starting fluid in the carb, and in the spark plug holes then installed spark plugs and still nothing. i've only put my finger over #1 spark plug hole and i can't keep it on there pulling the cord, i'll try putting my pressure gauge on them when i find it. around what psi should i see?
I'm at a loss why this thing does not at least have the cylinders fire for a bit with the starting fluid. i doubt at this point it's the carb, not with using starting fluid i should get the thing running for at least 1-2 seconds but it barely wants to kick once. so now i'm wondering if maybe i should pull the reed block and inspect those?
and it seems like it's getting good compression but i wonder if it's weak.
serial number is 0B294290, that's zeros, and exploded diagrams can be found on the web mainly boats.net.
motor sat for last 4 or so years. shortly after taking ownership, i tried fixing the idle problem: cleaned carb and put a new carb kit on it, did not fix. also put new ignition box in it. best of my knowledge it never had a spark problem. after that i came to the conclusion i needed a new carb because the original one has a thin idle tube that comes up through the middle of it to the idle well on top where the idle mixture jet is. i tried manually putting a vacuum on that on the bench and it would not pull fuel. nor when i had it running i would shut it down and pull the cover off the idle well on top and it would be dry.
got around to buying new carb and tried starting it tonight but no luck. only thing different is i bought the 15hp carb which fits the motor fine and it was also cheaper. as far as i know the only difference between the 9.9 and 15 outboards is the carb and everything carb-wise is the same except the round throat on the reed block side is larger by a few millimeters.
motor fires once pulling the cord which puts the pistons through maybe 4-5 strokes but will not run. i've checked spark on each plug and it is strong. i've checked timing on the flywheel with a light and it's within range. i've sprayed starting fluid in the carb, and in the spark plug holes then installed spark plugs and still nothing. i've only put my finger over #1 spark plug hole and i can't keep it on there pulling the cord, i'll try putting my pressure gauge on them when i find it. around what psi should i see?
I'm at a loss why this thing does not at least have the cylinders fire for a bit with the starting fluid. i doubt at this point it's the carb, not with using starting fluid i should get the thing running for at least 1-2 seconds but it barely wants to kick once. so now i'm wondering if maybe i should pull the reed block and inspect those?
and it seems like it's getting good compression but i wonder if it's weak.
serial number is 0B294290, that's zeros, and exploded diagrams can be found on the web mainly boats.net.
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