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Mercury 9.9 tuneup procedures?


Boater59's Avatar
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Join Date: Jul 2006
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VA

04-12-09, 08:39 AM   #1  
Mercury 9.9 tuneup procedures?

Got an older Merc 9.9hp probably 10-12 years old. Once started it's runs great. ZI really hardly use it and it sits in the shed most of the time. I alway run pickled gas (w/Stabil and other storage additives) so any fuel left in the fuel bowl(?) should be fine. Anyway it's hard to start and more tugs than it's worth sometimes to get it started.

What can I do (myself of course) as far as the basics are concerned, to get it to start easily, and to sirt and idle and transition in/out of gear wiothout stalling in the form of a tune up or idle adjustment etc.?

Also with all the tugging it takes to start, I'm sure it's not doing the pull cord any good and it will eventually break and I will need to replace it as well.

 
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goldstar's Avatar
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04-12-09, 11:39 AM   #2  
First, pull and check the spark plugs. Clean or replace as needed. The spark gap is .060 inch.
Next, remove the fuel filter under the carb. The clear bowl unscrews to get to the filter. Clean the filter with solvent and replace. The idle screw is above the throat of the carb and may need to be adjusted.

While you are at it, drain and replace the grease in the lower gear case. That wont help it run better but will save major repairs.


Woody


You can trust your car - and a whole lot more - to the man who wears a star.

 
Boater59's Avatar
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04-16-09, 01:05 PM   #3  
Okay sounds easy enough I guess. Sort of what i figured but these outboards can be like motorcycle engines in terms of not being easy to figure out problems.

Will adjusting the idle screw help it start easier? Is there a air-mixture screw or no, just idle speed?

 
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04-16-09, 08:32 PM   #4  
The idle screw won't help it start and I don't like to adjust them untill I've checked everything else. If the motor ran good in years past adjusting this only masks the real problem they wont go out of adjustment.
Start with new spark plugs and a compression test.

keep us posted, good luck

 
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04-22-09, 01:38 PM   #5  
I'll do just that...thanks

BTW what's the suggested/factory starting procedures in terms of choke X pulls, then off choke, throttle position etc.?

 
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04-23-09, 05:46 PM   #6  
Mine is a 1999 - 10 years old. From the manual:
1. Open fuel tank vent
2. squeeze primer bulb several times
3. set lanyard stop switch to run
4. Set throttle grip to start

5. turn primer/idle speed knob full clockwise
6. When engine is cold, pull out and push in the primer/idle speed knob one to three times. Leave the knob in the pulled out position when starting.Pull the starter rope slowly until you feel the starter engage, then pull rapidly to crank engine. Repeat until motor starts.
7. Push in primer/idle knob after engine starts. If engine begins to stall, re-prime until engine is running smoothly
8. Turn primer/idle knob as engine warms up to obtain desired idle speed.
9. Check for water flowing out of fuel pump indicator hole.

Good luck.


Woody


You can trust your car - and a whole lot more - to the man who wears a star.

 
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04-24-09, 02:55 PM   #7  
Great...thanks. I never got any manuals etc. when I purchased it back in 2004. Thinking about selling it since i don;t use it often enough. It's probably around a 1999 as well. What would be a reasonable ballpark price for if i sell it assuming everything is in good working order?

 
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