# yamaha 9.9 outboard help.



## meboater (May 4, 2008)

Hey all-
The motor is a 2008ish 9.9 high thrust.

At the end of last season, it ran, but would not idle smoothly, and needed fiddling. After properly storing for the winter, it would not start. After spraying some carb cleaner in the air intake, it would spark, but not start. Fuel made all the way to the carb, so I removed the carb.










Found grunch in here, cleaned it out. Also passed a wire through the main jet, and sprayed with cleaner. There was what I believe is a second jet, but too small to clean. Sprayed with cleaner.

The motor now starts, and runs reasonably smoothly, but, is hard to start. there is no choke, and AFAIK, it is supposed to start in neutral, no throttle, using just the key. It does not. After a bit of messing, it will start at half throttle, and need to warm up before going down to idle.

There are three adjustments, 2 I think I understand, 1 that I don't:










1: idle
2: throttle linkage. affects when the throttle responds. Should not be used to adjust idle.
3: no idea. It has an adjusment, and when I had the carb off, it appeared to move a small, gasketed cylinder in the bottom of the float bowl.

What does number three do?

Other thoughts:
Any chance ther is any problem with the vacuum lnes? The boat has no choke, and as I understand it, the vacuum lines play a role in starting, idling, etc, as a choke would.










last but not least- No air filter. can this be right?









I appreciate anybody's thoughts or experiences with this. 
This board has always been a big help on matters like this.

HH


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## WouldaShoulda (Oct 7, 2008)

I have a slightly older one. The PDF owners manual is of no assistance.

You (both of us) need a shop manual of some kind.

Mine has instructions on the throttle handle to apply throttle for cold starting and none for warm starting. But again, mine is several years older.


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## dabnis (Jul 29, 2007)

Not familiar with your particular motor so I am kind of guessing but I think #1 may be a limiter associated with the shift mechanism. #2 looks like the idle speed adjustment. 
#3 could be a cable lenght adjustment fitting. I had the same problem with a Honda 2HP .
Cleaned the carb out as best as I could, mostly solved the problem but could never get it to run spot on. Solution, a new carb, runs perfectly. If there is a drain plug or fitting on the carb, suggest you drain it if it is going to sit for more than a couple of weeks. You really need a good manual to know what everything does.

Paul T


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## INMA (Sep 13, 2011)

First thing is the engine probably has an electrically operated choke which has a solenoid (the round black thing on the engine). I am not sure whether the choke is energised for it to be on or whether its on then energised to go off.

There are basic things to check troubleshooting an engine that is hard to start. Fuel, air and spark are the basics to check before pulling things apart.

Spark is a classic because people leave the emergency lanyard off and wonder why they can't get an outboard to fire up.

Any basic manual should give you enough to figure out where to look for the cause of your starting problems.


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## sailguy40 (Feb 6, 2010)

Sounds like a dirty carb. I just had a similar problem with my Nissan 9.8. Mine would start after a couple tries but if i drop throttle below half it would sputter and die. I spray cleaned it 4 times with marine carb cleaner still no luck. I tried fuel treatment, no luck. I replaced fuel filter and spark plugs and you guessed it, no luck. A mechanic told me i did not clean the carb. I needed to do a thorough cleaning. This meant disassembling the carb completely, all jets, nozzle, etc and soaking it in carb dip for 4 hours. Then spraying all parts with carb spray and putting it back on. Well i did this and it worked. It was actually my slow jet i think that was clogged. That small jet you mention, spray alone wont clean it. Try those things above and i bet it will work. Oh and change fuel filter on motor and tank as well as spark plugs. Another thing make sure all fuel lines are free and clear.


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## jimpbradley (May 8, 2012)

I'm new and this isn't a reply, but I have a new to me Pearson 26 One Design. I measured a Johnson long shaft and the bottom of the motor would hit my rudder. Is this a problem with other outboard long shafts? Help!


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## olson34 (Oct 13, 2000)

And Where.... is a Moderator when we need one?


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## Cruisingdad (Jul 21, 2006)

olson34 said:


> And Where.... is a Moderator when we need one?


Holy Macaroni! THat was the longest freaking spam message I have ever seen!

Brian


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## gershel (Feb 4, 2001)

The choke solenoid sits atop the carb. That may need to be cleaned or replaced. Try holding the linkage to see if the choke is the problem. I have 2 9.9,s and before I try to start them, I aways pump the throttle about 5 times.
Seems to work for me.
Marc


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## pdqaltair (Nov 14, 2008)

I have 2 of those motors. Lots of good advice and trouble shooting guides can be found on the PDQ forum, as ALL PDQs use these.

#1 is the accelerator pump. Really just a fitting adjustment and should not need changed.
#2 is the idle stop.
#3 is a fitting adjustment for the throttle, probably not needed to adjust.

Some models have idle mix screws, but I can't see; it is on the top of the carb. Still, if it ran before, the problem is dirt and not adjustment.

Yes, pumping the throttle before starting is common on these motors. 2-5 times should do. As everyone posted, mostly what she needs is a good cleaning.

Yup, ethanol and water is the problem. Under the dirt is probably corrosion as well. There are additives that will help a great deal:
Sail Delmarva: Gasoline Additive Corrosion Testing

And vent filters help by keeping the water vapor out. These have been shown to reduce fuel breakdown and corrosion in both gasoline and diesel; Practical Sailor has done multiple rounds of both field and on-boat testing:
Sail Delmarva: Gasoline and Fuel Tank Vent Filters

Shop manuals came with mine--good dealer! Maybe they'll sell one. Shipyard Island Marina, 800-213-3323.


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## Ross 1955 (Aug 22, 2014)

I realize this is some time later than the original post but maybe it will help others with the no idle issue. 
I just recently experience the same problem.
I removed and disassembled the carb I found two pieces of foriegn matter under the plate that resides on top of the carb. At first I thought they were pieces of dried fuel enamel. But after a close inspection with a set of loops I realized they were seed pods from a birch tree. Which I do have several of around my house.
So then I wonder how the heck these would get past the filtering system of the motor. And to my surprise there is no filter system. Just a baffle.
This was a first year 8.8 high thrust. My neighbor just bought they new 9.9 and also to my surprise there is no filter media in his motor either.

As far as I’m concerned ALLLLLL gas motors should have more than just baffling. The air is caulk full of motor killing abrasives. To correct I bought some 60 PPI filter foam and put it in the lid of my Yamie. 
Other than this particular issue this has been one great motor.


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## ianjoub (Aug 3, 2014)

I have been doing powersports mechanics my whole life, Yamaha included, but no work on outboards.

Is this 2 or 4 stroke?

The small jet is the pilot jet. It needs to be cleaned. I unwrap a piece of speaker wire and use 1 strand of the copper to run through the pilot jet to clean, followed by compressed air.

After that, there is likely and idle mixture screw. It is an air screw on 2 stroke, and a fuel screw on 4 stroke. Turn it in lightly to seat, counting the turns. Remove it and blow compressed air through there, then reassemble to the same number of turns out. Be careful, there is a washer, spring, and o-ring in there that you don't want to lose.

If you do this successfully, it will start easily and idle properly.


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## ianjoub (Aug 3, 2014)

Holy batman .... this original post is 2 years old. I assume he got it sorted years ago ... :lol:


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## megawatt (Dec 2, 2019)

meboater said:


> Hey all-
> The motor is a 2008ish 9.9 high thrust.
> 
> At the end of last season, it ran, but would not idle smoothly, and needed fiddling. After properly storing for the winter, it would not start. After spraying some carb cleaner in the air intake, it would spark, but not start. Fuel made all the way to the carb, so I removed the carb.
> ...


on top of the thermal heater coil of the choke/ starter set there is a small screw which adjusts the amount of fuel that enriches the mixture on starting. wind the screw out till its about flush with the top of the coil.


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## megawatt (Dec 2, 2019)

Also undo the screws and take the black coil part off and look for debris inside


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## Minnewaska (Feb 21, 2010)

Welcome aboard megawatt. You’re probably not accustom to the posting dates yet. They are noted on the top left of the post. This one was posted over 7 years ago. Nothing wrong with adding more info to an old post, it’s just very unlikely the poster will see it. This poster hasn’t even signed onto the site, since 2013.


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