1988 Johnson 9.9 w/15 hp carb won?t start/has fuel, spark & compression???

ammoruss1

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This is a little long, but I wanted to provide you with as much info as possible.

The model is J10RCCD (1988) 9.9 hp Johnson
Numbers I found on the carb MX433333 (on the metal body). It has the plastic top with 5 screws and the number 337833 (I think it?s a 1992 15 hp carb).

I bought it a few weeks ago and when I went to pick it up the guy had the cowl cover off (which now, I think might be odd). He fired the motor right up. He told me it was 9.9 with a 15 hp carb that he had as a "spare" and hadn't used it in a few years (it just sat in the corner of his garage). He showed me the water was peeing out the back so the impeller was working but he recommended I keep an eye on it. I laid the motor on its side in my Tahoe (throttle handle facing up) and drove it 1 hr home then hung it on the back of my boat. I didn?t have a fuel tanks so I just left alone for about a week. I noticed gas/oil coming from the exhaust/prop. I loaded it back into the Tahoe and took it to the local boat repair place and asked them if the oil by the exhaust was normal. Their mechanic looked at it (and smelled it) and said it was exhaust and not to worry. I bought OEM 2 stroke oil, OEM fuel line, OEM impeller kit and OEM lower unit oil. I replaced the lower unit oil (old oil was a little dark) and installed the impeller kit. I purchased a fuel tank (Atwood 3 gallon from Cabela?s) and tried to start the motor?no luck.

I text the guy I bought it from and he said, ?I started it for you?. Basically, I felt like he didn?t want to help. I asked if there were any tricks to getting it fired up and he was short with his answer again and didn?t help.

I?ve since check the compression ~95 PSI on both cylinders. I hooked up a light to my spark plug wire and it lights up when I pull on it. I?ve checked the gap on the plugs (they were at .038 and I re-gapped them to .030). I also got a new set of plugs and gapped them to .030?still no luck.
Seems like it almost starts the first pull after its been sitting a while, but it doesn?t start and eventually floods (same oil/gas eventually starts to drip out through the exhaust). I?ve tried every combination of choke/throttle I can think of. I?ve pulled the plugs, disconnected the fuel lines and pulled it a few times to dry it out.

I haven?t tried starting fluid because I?ve read mixed reviews on using it.
I haven?t pulled the carb off to rebuild.
It does have 2 kill switches?one at the end of the handle (with clip installed) and one by the pull starter. I haven?t messed with them at all because I saw it run when I went to pick it up.

I called two boat repair places. One wanted $125 and the other $90 to diagnosis the problem.

What can I try next? Any info/guidance is greatly appreciated.

Ammoruss
 

ryanorillia

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Mar 28, 2015
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does your primer bulb get hard? are you certain it's getting gas? it could be old oil/unburned fuel coming out from the cylinders when you're cranking it over??
i'd disconnect the fuel line to the carb from the fuel pump and make sure it's getting gas
 

racerone

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Remove 4 screws on air box to look at the choke flapper.---Does it close and stay closed when you pull the rope ?
 

Faztbullet

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Also check that fuel line installed correctly and arrow on bulb is toward motor
 

boobie

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Check your spark. It should jump a 7/16" open air gap on a tester. $ 8.00 at local parts house.
 
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ammoruss1

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Boobie, thank you for for the response. I bought a spark tester from the local parts house with a light bulb in it. The light comes on when I pull the rope on both plugs. Is that good enough to eliminate spark as the issue or do I need to go get the other tester and verify it can jump 7/16" on the other type of tester?
 

caliber

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Apr 7, 2015
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It comes down to you do not have enough gas or enough spark. I would not trust a bulb type tester I would buy a different kind or just use the spark plug. Are you possitive it is flooding have you pulled a plug and seen if its wet. If you do not want to use spray put a little gas in a oil can and give it squirt down the carb. (Do not keep the can near you move it accross the shop before trying to start if it back fires it is recipe for disaster) If you are possitive it has spark you can rule out kill switches but i have seen lots of people bump them and its enough to make them not start I would take rope one off and clip it back on just to be sure. also change the plugs you might of just fouled them. Then your bulb would show spark and the plug would not. Put 2 new in it could be as simple as that i've seen plugs foul so bad they won't start.
 
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ammoruss1

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Caliber, thanks for the response. I'm positive it is flooding. After pulling on it for a while, I pull the plugs and they are wet, plus It seems like I get a little gas/oil mixture coming out of the exhaust ports in the prop. I bought a new set of plugs and go back and forth once I soak one set trying to start it. I've tried unclipping and reclipping the kill switch as well. Once I confirm the spark, I'll try putting a little gas in the carb.

Boobie, thanks. I'll get an open air gap tester tomorrow and give it a try.
 

Bullie

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Could it be that he has sheared the key in his flywheel, altering the timing?
 

gm280

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Well if you have gas (fresh gas I hope) and correct oil mixture and spark and compression, then like Bullie stated above, is the "Timing" off? If the timing is even a little off you can crank until your haves fall off and it will not start... So make sure your timing is correct. And if the timing is correct, then recheck the compression and spark again, because something just doesn't add up.

One other thing you could try after thinking about this for a while. Remove the fuel line to the carb and either plug it or allow it to drain into a container to capture the fuel. And then mix up a little squirt bottle of 50:1 gas/oil mixture and squirt just a little into the carb opening so it doesn't flood the engine to see if it pops and/or cranks like that. If so, your carb is in need of a carb kit!
 
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ammoruss1

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All,
Thank your for the responses and ideas.

It is still not running, but here is a list of things I've tried/verified as suggested:
It has fresh gas and the right oil mix (50:1). double checked the primer bulb...its hard. I disconnected the fuel line from the carb...it squirts out if I pump the bulb or pull the rope. Choke flapper is staying closed. fuel line arrow is going in the right direction. I bought an air gap tester and got spark at 7/16" on both plug wires.

Its getting late and I dont want to upset my neighbors, so tomorrow I'll regap the plugs to .040 as suggested. squirt a little gas in the carb and see if it starts.

I dont know anything about timing or the "key" in the flywheel as a few of you mentioned, but I'll search online and see what I can find.

just to clarify, i have got it to pop and almost run a few times...does that mean I just need to rebuild the carb? The motor was sitting for a few years in a garage before I bought it (but it did start and run fine the day I bought it). Just haven't been able to start it since I got it home.

Any other ideas?

Thanks again,
Ammoruss
 

ammoruss1

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****UPDATE****
I got the motor running! I pulled the carb and rebuilt it and the motor came alive!

Thanks for all the help!
 
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