Poorly Running 9.9 Merc Outboard - SailNet Community
Reply
 
LinkBack Thread Tools
post #1 of 18 Old 04-17-2009 Thread Starter
Member
 
Join Date: Nov 2008
Posts: 58
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 7
 
Poorly Running 9.9 Merc Outboard

I've searched for advice on my outboard issue and all of the results seem to be conflicting.

I have a 2001 Mercury 9.9 outboard on my Catalina that I bought in November. When I bought it the engine would start fine, but once I got going at 1/3-1/2 throttle the engine would eventually bog down and then turn off. Restarting was not possible unless I started it in gear, but then it would eventually cut off. The choke would change its running habit, but only for seconds, then it would turn off again.

I changed the plugs a few weeks ago and initially it ran super and I thought the problem was fixed. A couple of sails later and it runs the same as when I bought it. It initially starts great and it will idle just fine, but once I get going it will bog down and turn off and restarting is nearly impossible unless in gear.

I'm pretty frustrated at this point. The original gas that was in the tank when I bought it has been exchanged and fresh gas/oil mixture is running in the tank. I'm sure the plugs are fouled, but I have not confirmed that, only an assumption since it is back to running poorly.

I have a manual for this engine, but don't know where to start and don't have time to rebuild anything on my own. Can anyone suggest anything simple to check or am I in for a carb rebuild? At this point I can't sail this boat since I am fearful of not being able to return to dock.

Thanks in advance,

Chris
SpeedAgent is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #2 of 18 Old 04-17-2009
Telstar 28
 
sailingdog's Avatar
 
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 15 Times in 12 Posts
Rep Power: 14
         
Given that you don't know the age or status of the spark plugs, changing them with new ones is probably a good start. Rebuilding and cleaning the carburetor is also probably good idea.

Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
sailingdog is offline  
Quote Quick Reply Share with Facebook
post #3 of 18 Old 04-17-2009
Senior Member
 
Lostmt's Avatar
 
Join Date: Jun 2006
Location: Texas
Posts: 160
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 10
 
I had the same problem. The last time it died was in the ICW with tons of tow and power boat traffic with a head wind. No way to tack out to open water. Very hard on the nerves.

Here's what I did.

1. Cleaned and added another fuel filter. Glass see through.
2. Cleaned the carb. Lot of green junk growing in the carb.
3. Changed the fuel and add Star Tron. I would not recommend Sea Foam.
4. Got new plug. Recommended by the Suzuki. That way I know I have the correct plugs.
5. I now keep a can of spray carb cleaner on the boat.

My 8hp Suzuki 2 stroke is still a little hard to start but runs fine now. Once its warmed up it starts on one pull.

You might find one of your dock mates that will clean your carb for you. One of mine did it for me and only took about 30 minutes. I watch him and now I know how to do it myself. If I had taken it in it would have cost me a couple hundred bucks.

Last edited by Lostmt; 04-17-2009 at 09:05 AM.
Lostmt is offline  
Quote Quick Reply Share with Facebook
post #4 of 18 Old 04-17-2009
Member
 
raisin56's Avatar
 
Join Date: Jul 2008
Location: Tampa, Florida
Posts: 45
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
I too had a similar problem, it turned out to be that the ethanol gas had loosened the varnish that had built up in the fuel tank. As the engine ran the debris would build up around the strainer in the tank and choke off the fuel flow. Shut down the engine and it would drop clear and all work fine for awhile. I had to empty the tank and flush it clean, replace all filters and hoses. Then run a tank of gas with carburetor cleaner in it to finish the job.

Dan
raisin56 is offline  
Quote Quick Reply Share with Facebook
post #5 of 18 Old 04-17-2009
Senior Member
 
Lostmt's Avatar
 
Join Date: Jun 2006
Location: Texas
Posts: 160
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 10
 
Here some information on ethanol fuel problems. Sea Foam also contains alcohol.

http://www.starbrite.com/whatsnew/ST...%20p3072D2.pdf

It can be purchased at WalMart in the boating section.

Last edited by Lostmt; 04-17-2009 at 11:07 AM.
Lostmt is offline  
Quote Quick Reply Share with Facebook
post #6 of 18 Old 04-17-2009
Telstar 28
 
sailingdog's Avatar
 
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 15 Times in 12 Posts
Rep Power: 14
         
Be aware that ethanol blends are not as stable as the previous MTBE based gasolines. The ethanol tends to absorb water from the humid air and once it reaches 1.5% water by volume or so, it phase separates out from the gasoline, leaving you with fuel that has an octane rating of somewhere around 80...

Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
sailingdog is offline  
Quote Quick Reply Share with Facebook
post #7 of 18 Old 04-17-2009
Senior Member
 
timebandit's Avatar
 
Join Date: Sep 2002
Posts: 928
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 13
 
Two stroke or four stroke?

Rick
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Mac 25
Copernicus
Southern California
I am not a prejudice racist sexist bigot. I just hate stupid people.
timebandit is offline  
Quote Quick Reply Share with Facebook
post #8 of 18 Old 04-17-2009
Senior Member
 
Lostmt's Avatar
 
Join Date: Jun 2006
Location: Texas
Posts: 160
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 10
 
Quote:
Originally Posted by timebandit View Post
Two stroke or four stroke?
It doesn't matter. Ethanol fuel will cause problems. Same with any additive that contains alcohol.
Lostmt is offline  
Quote Quick Reply Share with Facebook
post #9 of 18 Old 04-17-2009
Junior Member
 
escapaide's Avatar
 
Join Date: Jun 2008
Location: Florida
Posts: 17
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
I had a similar problem and found that if i squeezed the promer bulb on my fuel line it would continue to run, i assumed the fuel line had a smal air leak and replaced it and the motor runs fine now

Steve
escapaide is offline  
Quote Quick Reply Share with Facebook
post #10 of 18 Old 04-17-2009
Old as Dirt!
 
svHyLyte's Avatar
 
Join Date: Nov 2008
Location: Tampa Bay Area
Posts: 2,935
Thanks: 15
Thanked 129 Times in 122 Posts
Rep Power: 7
 
I had the same problem with a 2001 15hp version of the engine (up-tuned version of the 9.9)--so much so that I bought the 5 year warranty from Mercury before the original factory warranty expired. The motor made 5 trips back to the dealer in Sarasota without improvement. The 6th trip--to another shop-proved the fix. It seems that there is a small adjusting screw on the carb that needs be adjusted "just so" (it's actually described in the owner's manual as pointed out by the tech at the second shop). With that adjusted properly, the engine seems to work fine. Without--Not. I would say that its a mixture control but when I suggested that, the tech said it wasn't so I don't know what it actually moderates. It's above and somewhat to the right of the carb barrel as you're facing the motor from the normal user position.

FWIW...

s/v HyLyte

"It is not so much for its beauty that the sea makes a claim upon men's hearts, as for that subtle something, that quality of air, that emanation from the waves, that so wonderfully renews a weary spirit."
svHyLyte is offline  
Quote Quick Reply Share with Facebook
Reply

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now



In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.


User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
Is it possible to update / convert a Merc outboard??? MABON01 Gear & Maintenance 4 09-03-2008 01:59 AM
Merc outboard won't idle JewelledJester Gear & Maintenance 4 05-21-2008 02:32 PM
Outboard Running Problems VASailor10 Gear & Maintenance 7 12-10-2007 06:30 PM
my 9.9 mercury outboard has no spark danjarch Gear & Maintenance 4 06-24-2007 07:27 PM
Running Backstays Dan Dickison Gear and Maintenance Articles 0 05-14-2002 08:00 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome