2000 yamaha 9.9

[Mausermike14]

hey everyone, hope someone can help me out on this one or maybe you have had the same problem. I have a 2000 yamaha 4 stroke 9.9 high thrust that just won't stay running. So far this is what I have done to it, new fuel pump, new fuel lines( boat side), new priming ball, new pick up tube in tank, new water separator, new fuel quick connects on both engine and fuel line side. Carb has also been redone, cleaned, soaked and new carb kit installed. Here is what is happening, i pump the priming ball up and the ball goes hard and the engine starts. It will run through the choke cycle and idle fine for about 3-5 minutes then run out of fuel. I check the ball it is still hard,Then I hit the start button and it fires right back up. Keeps doing it over and over again. Doesn't matter if your at idle or in gear with the revs up it keeps dying. I have checked the vent and it is clear. Tried running the engine on a separate tank and it does the same thing. I asked a yamaha mechanic about it and he said its a carb issue, but this carb has been cleaned and cleaned 3 times now and still the same issue. Maybe I need a new carb?? Hope someone can help me out, before I spend $500 on a carb for this yamaha thanks in advance

 

[Trophy]

Priming balls usually have arrows to indicate gas flow, check that it is installed right. Besides water separator, any other fuel filters in line or on engine?

 

[fish brain]

I had a similar issue. My problem was a piece of debris that was getting stuck in the float valve. If you don't feel confident taking the carb apart your self maybe try a different mechanic. If you choose to open it up there are lots of good how to videos on youtube. They are really not that complicated.

 

[casper5280]

By the time you pay a mechanic to rebuild a carb you may as well just buy a new carb and install it yourself .

 

[scott craven]

Priming balls usually have arrows to indicate gas flow, check that it is installed right

This !!

 

[wavetamer]

that does sound like a low speed jet issue . you sure you pulled and removed the low speed jet it has holes the size of a pin and have to be cleaned to perform correctly, there usually a little cap you have to pull off

 

[profisher]

It will be the carb...they are very hard to get clean...I have one for my 9.9 that I've cleaned twice and the motor will run...but not right ...it runs a bit rough (shakes) and the idle speed wonders a bit. Finally robbed the carb off my spare motor and it runs perfect. I'll go at the carb again when my season is over and I can take my time.

 

[Mausermike14]

Priming balls usually have arrows to indicate gas flow, check that it is installed right. Besides water separator, any other fuel filters in line or on engine?

I did check the flow of fuel and the arrow is pointing in the right direction. I do have another inline fuel filter underneath the cowling on the engine and I have already replaced it

 

[Mausermike14]

I had a similar issue. My problem was a piece of debris that was getting stuck in the float valve. If you don't feel confident taking the carb apart your self maybe try a different mechanic. If you choose to open it up there are lots of good how to videos on youtube. They are really not that complicated.

I will take it apart again and see if there is something I have missed. Thanks

 

[Mausermike14]

i

that does sound like a low speed jet issue . you sure you pulled and removed the low speed jet it has holes the size of a pin and have to be cleaned to perform correctly, there usually a little cap you have to pull off

I did pull it out and did find some crap in there, but possibly didn't get it all out. I will take it apart again and hopefully get it this time.

 

[fish brain]

i

I did pull it out and did find some crap in there, but possibly didn't get it all out. I will take it apart again and hopefully get it this time.

you can blow it out with air, or use copper wire to clean the orifice. I did both. For the copper wire I used some multi strand wire and twisted a couple together until they just went through without being tight. If worse comes to worse, take the whole carb apart and run carb cleaner through each hole and needle valve.

 

[Mausermike14]

you can blow it out with air, or use copper wire to clean the orifice. I did both. For the copper wire I used some multi strand wire and twisted a couple together until they just went through without being tight. If worse comes to worse, take the whole carb apart and run carb cleaner through each hole and needle valve.

Thats what is puzzling me about this carb, I did all those things already to it, and it still doing the same thing I'm going to try it again, or maybe get it ultrasonic dipped. This is the first carb that has given me this much trouble

 

[fish brain]

Dumb question
Did you count the turns in on the needle valves before you removed them, and then set them back to where they were when you replaced them? or did you just screw em down snug?

 

[Dorman Point]

Also check the needle valve on the fuel connection at the engine, and the sprung ball in the fuel line from the tank. Make sure they both depress smoothly. I have had this problem.

 

[profisher]

Ive used a stiff 15 pound test mono line in the pilot circuit on my CB 750 carbs to make sure they were clear. The mono won’t scratch the passageway which can effect fuel flow. On the 9.9 carb I usually just let it soak in carb cleaner, rinse in water and then blow out with a compressor.

 

[Mausermike14]

Dumb question
Did you count the turns in on the needle valves before you removed them, and then set them back to where they were when you replaced them? or did you just screw em down snug?

Not a dumb question at all I counted the turns on the idle mixture screw and used it as a starting point to set it.

 

[Mausermike14]

Also check the needle valve on the fuel connection at the engine, and the sprung ball in the fuel line from the tank. Make sure they both depress smoothly. I have had this problem.

That was one of the things I was hoping it was, but I replaced both sides( engine and fuel line side). I will double check it and see if its going in all the way, thanks!

 

[Mausermike14]

i

Ive used a stiff 15 pound test mono line in the pilot circuit on my CB 750 carbs to make sure they were clear. The mono won’t scratch the passageway which can effect fuel flow. On the 9.9 carb I usually just let it soak in carb cleaner, rinse in water and then blow out with a compressor.

I will give the mono line a try when I pull it apart again this weekend, thanks!