small outboard issue
Moderators: bman, Chalk, Tom Keels
small outboard issue
I’ve been experiencing motor issues on a small outboard I own and was hoping one of you might be able to give me some advice on how to fix it. I can take it to the mechanic but before doing so I’d like to see if this is something I can fix, that is with a little help from my forum friends. The motor is a 2000, 9.9 Merc 2 stroke. The engine starts and ideals without issues. The problem is I’m only getting about ¼ power at full throttle. So far I have checked the fuel lines from the tank to where it enters the carb and found no blockage. I’ve sprayed carb cleaner into the carb. I also sprayed it into the hole where the gas line enters the card along with compresses air in the hopes of clearing up any blockage. I’ve pulled the spark plugs, cleaned them and put them back in. They looked good so they haven’t been replaced.
Any advise would be greatly appreciated.
Any advise would be greatly appreciated.
- Flint River Pirate
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Re: small outboard issue
Sounds like maybe an air leak in your fuel line? Did you check that?

Team Jolly Mon
- Flint River Pirate
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Re: small outboard issue
Sounds like maybe an air leak in your fuel line? Did you check that?

Team Jolly Mon
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Re: small outboard issue
MIGHT WANT TO CHECK THE AIR VENT ON THE TANK CAP, IF IT IS NOT OPEN IT WILL CREATE A VACUUME IN THE TANK AND WILL NOT LET FUEL FLOW PROPERLY.
PA
SEMPER FI

PA
SEMPER FI


FUTCHCAIRO
- robbankston
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Re: small outboard issue
HIgh speed jet on the carb might be clogged. Seafoam treatment might help.
A good plan violently executed now is better than a perfect plan executed next week. -George S. Patton
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Re: small outboard issue
Here's a quick fix...........Porter Marine
9355 Elgin Road
(850)421-1490
9355 Elgin Road
(850)421-1490
- Flint River Pirate
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Re: small outboard issue
X2One Keeper wrote:Here's a quick fix...........Porter Marine
9355 Elgin Road
(850)421-1490

Team Jolly Mon
Re: small outboard issue
I second the Sea Foam. Try it first.
- onefishtwofish
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Re: small outboard issue
Sounds just like our problem with a Johnson 9.9. Turned out to be the bulb was rotting from the inside and sending little chunks of rubber into the jet of the carb. We cleaned it out twice, ran in new fuel and it would do it again on the next trip. Finally realized it was a bad bulb and we cleaned the carb and fuel pump one last time and it has run like a top since.
Ducks, turkeys, flats fishing. Who has time for golf?
Re: small outboard issue
Thanks guys for the suggestions. After doing about everything I could pertaining to fuel blockage without success I went back to the spark plugs. It turned out one of the plugs was only working part of the time. I replaced them and now the engine works good as new. Thanks again.
- fishinfool
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Re: small outboard issue
Glad you got her fixed. It is nice to know that your fuel system is clean too.
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Re: small outboard issue
After reading some good advice from you guys I thought I would see what you guys think about the issue I'm having. I have a carbureted 25 hp Nissan. I pump the bulb til it's tight and then try to crank it and it may fire off and then it shuts right off. After that it won't crank at all unless I spray starting fluid in the carburetor and then it still only runs for a second. At first I thought maybe there was a clog in the gas line, I took the fuel line off where it goes in to the carburetor and pumped the bulb and gas comes out. Pulled the line off where it comes out of the diaphram(?) and it pumps as I hit the key. Seems to me that the line is free, is there a chance that where the fuel enters the carb is clogged? Any suggestions?
Re: small outboard issue
fishing coach, I bet you a dollar to a donut that Pa will advise you to first assure that your gas tank vent valve is open. 
Fishin' is the mission.

Fishin' is the mission.
To fish, or not to fish, . . . those are the answers.
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Re: small outboard issue
I'll save him a post. Read his post earlier that said that and made sure it was open with no luck.
- fishinfool
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Re: small outboard issue
Check the spark plugs and plug wire connections, then the filter in the carb bowl. Sounds like a spark problem, but could be fuel.