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Honda 9.9 wont start

J

jaysbay

New member
I had not started my motor in about 6 months and now it won't start. I pulled the carb and took it all apart and ran it in my ultrasonic tank, I installed new plugs & gas filter and made sure the fuel pump is pumping, It has fresh gas . I can get it to run if I spray carb cleaner in the intake but that's about it. Is there anything I may be missing. Motor is a 2010 Honda 9.9 four stroke with 80 hours on it.
 
Hi,

Sorry you're having problems.

Do you remember emptying the carb prior to storage? These carbs will just not tolerate residual fuel left sitting in the float chamber for any length of time.

Electric start or pull start only?

I ask because the cold start enrichment on the two are different. Pull start has a manually operated choke cable and electric start uses a "rich default" with an electrically operated shut off "valve".

The manual cable type can be very problematic after it's aged and worn a bit but the electric Service Enrichment (SE) system, while typically very reliable, can also cause start problems when it fails.

Both systems need clean fuel supply feed passages. I have found "mud" in that passage many times when cleaning these carburetors.

I have also found that only using ultrasonic cleaning of the carbs on these is usually not adequate for getting them fully clean.

Some specific checks before reassembly....especially of the accelerator pump circuit delivery tube and orifice...are necessary to ensure proper operation.
 
jgmo thanks for the reply, Well I have it narrowed down to the carb for sure, If I give it a shot of carb cleaner and rev the motor to about 1/4 throttle it will stay running for a long while, As soon as I bring the throttle down to a idle it will stop running and will not restart unless I use the carb cleaner . It must be in the idle circuit ? . I broke the carb down as much as i could and I am soaking it over night. Tomorrow I will get my jet reamers out and try and clean all the jets again and the passages . I need to find a breakdown of the carb. It is a electric start so it does have that electric rich default your talking about, Do you know if that setup is removable for cleaning?
Thank you again
 
Yes, the SE electrical coil is removable. You should have removed it before submersing the carb in any liquid. Hopefully, it isn't damaged now.

If you truly want a comprehensive breakdown of the carb and instruction on how to properly clean it, I recommend that you get the Honda Marine Carburetion Manual. You can order that here:

Honda Marine | Shop Manuals Publications | Honda Power Products Support Publications

publications.powerequipment.honda.com publications.powerequipment.honda.com

That manual will save you from having to do what I have seen so many do before...
....take off, tear down, "clean", install....repeat.

Sometimes 6-7-8 times or more and still not get it right. Then, after being thoroughly defeated and frustrated, they end up buying a new carb. Which, in my view is just a waste because I've cleaned well over 100 of these or others like them and never trashed one yet. Although, some are tougher than others because they're so plugged up.

But your's doesn't sound too bad at all and should be if you are equipped with the knowledge that the manual provides and maybe a couple of tricks I've learned over the years
And, I would be happy to share those.


These carbs are just plain "technical" in the sense they provide precision fuel flow through VERY small passages and orifices mostly inside the main body. You can't see them or access them with anything other than carb spray.

Be careful poking around with "reamers" though because you CAN easily destroy a carb if you enlarge an orifice.

For now, you should immediately remove the SE valve and let it dry. Once it's dry, you can test it to see if it still works. But, even if it does, I don't think it's the original problem. I think this carb needs to be cleaned correctly if it's going to run the engine properly.
 
jgmo Thanks for the reply, I did remove the electrical part of the coil but the mechanical part was left in the top part of the carb.
I believe i must of missed a orifice / passage somewhere. I will give it another good cleaning and more carb cleaning and air pressure .
Thanks for the reply
 
I guess I'm not understanding.

The SE valve is held in place by a "C" shaped metal clip that slides into a grove in the valve's head. (item 16 in the link below). That clip is held in place by a single screw...item 17

When the clip is removed the entire SE valve assembly should pull out of the carb body in one piece...item 15


If that's what you removed and set aside, then there's no additional SE valve parts.
 
jgmo said:
I guess I'm not understanding.

The SE valve is held in place by a "C" shaped metal clip that slides into a grove in the valve's head. (item 16 in the link below). That clip is held in place by a single screw...item 17

When the clip is removed the entire SE valve assembly should pull out of the carb body in one piece...item 15


If that's what you removed and set aside, then there's no additional SE valve parts.
Click to expand...
I did remove 15,16 & 17 , I am going to give the carb a good cleaning today and I will get back to you on how its running. Do you have a good source or website that you use for Honda parts ? .
 
Well, I agree with you that the problem seems to be in the idle circuit. If that's true, you may need to remove the mixture screw to thoroughly clean that passage. It is a PITA but sometimes is very necessary.
You will need to destroy the anti tamper cap to access it. That cap is glued on with blue Loc-Tite. Some guys just pry them off but that breaks off the false head of the mixtures screw. I like to use heat to melt the glue and leave the head so I can use it to help get the screw backed out.

Look at the low speed emulsion tube (jet-set) VERY carefully...item 18 in the link. Those things can be impossible to clean and, when I was working on these things every day, I didn't even try. I would just replace them.

The little oring at the top of that tube is CRITICAL. I never reuse them and I apply Vaseline to them before installing the tube.


The vertical orifice in that tube is so difficult to clear it wasn't worth my time to screw around with it.

Also, those tubes will crack vertically. They are a pain.

While you have the tube out, spray cleaner into the port it attaches to and observe the idle orifice in the carb throat for flow.

Prop the throttle wide open so that you can see every delivery orifice....idle....transition and main/high speed.

Use the spray straw on the carb cleaner and cover each of the delivery orifices with the tip and "backflush" each one. In this case, pay special attention to the idle.

Locate the accelerator pump delivery tube at the front of the carb throat. Place the cleaner straw over the spray orifice by inserting through the carb throat from the throttle plate end. Make sure fluid comes out the pump delivery passage.

Spray into the accelerator pump delivery passage and VERIFY that fluid sprays from the accelerator pump tube orifice and out the back of the carb throat 8 feet.....that's right, 8 feet.

If that stream isn't 8 feet, keep spraying into the orifice to "backflush" and then into the passage entrance. Back and forth, back and forth until that orifice, brass tube and passage is open and delivering an 8 foot stream out the back of the carb.

If you don't do that, you're likely to have any number of symptoms with the way the engine operates.

There are two passages in the bottom of the float bowl. One feeds the accelerator pump piston and the other one feeds the SE circuit supply "well". Those can get packed with "mud" and you might need to use wire to clean them out.

Lastly, there are two passage entrances on the front carb flange. One is for low speed air jet and the other is main air jet.

Hose them out with generous amounts of carb spray.
It's a good idea to reverse flush everything.

Use your fingers to block off passages to increase the power of the spray.

Make sure your bowl air vents are open.

Just a couple of tips from an old man.

Good luck.
 
jgmo said:
Well, I agree with you that the problem seems to be in the idle circuit. If that's true, you may need to remove the mixture screw to thoroughly clean that passage. It is a PITA but sometimes is very necessary.
You will need to destroy the anti tamper cap to access it. That cap is glued on with blue Loc-Tite. Some guys just pry them off but that breaks off the false head of the mixtures screw. I like to use heat to melt the glue and leave the head so I can use it to help get the screw backed out.

Look at the low speed emulsion tube (jet-set) VERY carefully...item 18 in the link. Those things can be impossible to clean and, when I was working on these things every day, I didn't even try. I would just replace them.

The little oring at the top of that tube is CRITICAL. I never reuse them and I apply Vaseline to them before installing the tube.


The vertical orifice in that tube is so difficult to clear it wasn't worth my time to screw around with it.

Also, those tubes will crack vertically. They are a pain.

While you have the tube out, spray cleaner into the port it attaches to and observe the idle orifice in the carb throat for flow.

Prop the throttle wide open so that you can see every delivery orifice....idle....transition and main/high speed.

Use the spray straw on the carb cleaner and cover each of the delivery orifices with the tip and "backflush" each one. In this case, pay special attention to the idle.

Locate the accelerator pump delivery tube at the front of the carb throat. Place the cleaner straw over the spray orifice by inserting through the carb throat from the throttle plate end. Make sure fluid comes out the pump delivery passage.

Spray into the accelerator pump delivery passage and VERIFY that fluid sprays from the accelerator pump tube orifice and out the back of the carb throat 8 feet.....that's right, 8 feet.

If that stream isn't 8 feet, keep spraying into the orifice to "backflush" and then into the passage entrance. Back and forth, back and forth until that orifice, brass tube and passage is open and delivering an 8 foot stream out the back of the carb.

If you don't do that, you're likely to have any number of symptoms with the way the engine operates.

There are two passages in the bottom of the float bowl. One feeds the accelerator pump piston and the other one feeds the SE circuit supply "well". Those can get packed with "mud" and you might need to use wire to clean them out.

Lastly, there are two passage entrances on the front carb flange. One is for low speed air jet and the other is main air jet.

Hose them out with generous amounts of carb spray.
It's a good idea to reverse flush everything.

Use your fingers to block off passages to increase the power of the spray.

Make sure your bowl air vents are open.

Just a couple of tips from an old man.

Good luck.
Click to expand...
I ran the carb & parts one more time through the ultrasonic tank for 30 minutes and after removing it from the tank, I took a tall can of carb cleaner and went at it. Mounted it on the motor and she purrs like a kitten. The one thing I forgot, was to hook up the throttle cable lol, Hopefully I can reach in there and snap it on to the pivot ball. Thanks so much for the tips, I almost gave up and was going to buy a new carb, After looking at the price, I said nope.
 
Glad you got it.
Now, don't let it sit for more than 3 weeks without emptying the carb bowl. That will save you tons of headache.
 
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