One jet fell out of the pickup tube

[Poodlehead]

I was hoping the o-ring being pushed too far up in the pickup tube was my issue, but it wasn't. After removing the bowl yesterday, I put the O back on the bowl with Vaseline like you suggested, and reinstalled the bowl, but it made no difference.

One last thing I'm going to do before pulling the carb. With it running, spray carb cleaner around the sealing gaskets to see if it gets better. If it does, I know I have a leaking gasket issue.

Either way, once the carb comes off, I'm going through it. In addition to the jet and fuel passages, I'm assuming there should be some air passage that I need to make sure are clear too? Thank you!

 

[Poodlehead]

Finally an update:
After rebuilding the carb with new internal rubbers and cleaning the internal passages with wire, carb cleaner and compressed air, it runs better, but still still doesn't 'feel/sound' right.

I also sealed the plastic intake seams and put sealer between the carb and intake due to bowing on the plastic intake causing a leak.

I mowed for about 30 mins and it did ok, but it seems to cough occasionally, especially at lower speed.

There was a thin metal 'swirl plate' in the kit that I installed on the throttle side of the intake. It's supposed to be an update to swirl the air/fuel mixture, but I'm thinking about removing it to see if it helps.

I checked the plugs and I 'think' they look ok, but open to input. Thank you!

 

[Forest#2]

Post up a picture of the swirl plate you mention?
If it did not have one when you took it apart I probably would have not used such.

I do not trust the rubber intake o rings. I take flat gasket material and make paper gasket about 3/32 inch thick. You can even use a cereal box but about 2 or 3 layers of the cardboard box needed and I use permatex gasket sealer sparringly. You do not want any silcone gasket material to get loose and go into the intake.
If the rubber o rings are still stuck in the intake manifold I just leave them in place or you can disgauard, but do not trust old ones for a good seal.

Some of the newer kits have 3/32 inch thick fiber gaskets to replace the o rings. (note that the plastic intake manifold has steel bushings to limit the tightening of the manifold. The intake to head bolts can be tight but the manifold not sealed good due to the steel hollow bushings.

Be sure your spark plugs are gapped properly and I would install new ones in reference to the spit at low speed and make sure the magneto air gaps are same. Might have to just run it awhile under load and maybe eventually see that all valve lashes are ok. If the spit is back through the carb eventually check the intake valve lash. Sometimes you can see which side of the carb has the spit back if the breather is removed.
Them type carbs can sometimes really cause you you get some good Nikki Carb experience.

Be really sure you re-connected the breather hose on the back of the air intake.
You can confirm such with the breather removed. If you leave it loose the engine is eating dirt.

 

[Poodlehead]

I hear ya about not changing anything, but I was 'going for the gusto'! I really suck at taking pictures along the way, but here is a link I found talking about the Swirl Plate and reference to the Briggs service bulletin.

https://www.mytractorforum.com/threads/re-assembling-intake-manifold-to-carb.83566/

I used both new rubber O rings and paper gaskets where the intake bolts to the heads. The bushings are built into the mounting bolts with 'shoulders' to keep from smashing the o-rings too tight. The shoulder is pushing against the paper gasket instead of the metal surface of the head. I guess what you are saying is to use either the paper gaskets or o-rings, but not both???

Yes, I need to replace plugs and check ALL the gap settings before I dynamite this mower...

And YES, I need to make sure the breather hose is connected properly. I think I forgot about it when reassembling...

Thank you!

 

[StarTech]

The problem area is not where the intake mounts to the heads but is where the carburetor mounts to the intake. It can warp to where the is no seal in the center between the two barrels of the two barrel Nikki carburetors. I had to replace intakes because of this.

 

[Poodlehead]

The problem area is not where the intake mounts to the heads but is where the carburetor mounts to the intake.

Yes I saw that when I mounted the intake to the carb, so I ran some gasket sealer between the carb and gasket.

I'm going to pull the shroud off, run the engine, and spray some carb cleaner around the mating surfaces to see if anything changes... Thank you!

 

[Forest#2]

You say:
I guess what you are saying is to use either the paper gaskets or o-rings, but not both???

Yes you can use both. Sometimes the old square shouldered o rings do not want to go back in place so I just give them a toss.
Keep in mind that a slight spit can be due to carbon buildup inside the cylinder on top of the piston, as it gets hot the fuel/carbon can ignite when valve is part way open.
I've never had a problem that I noticed where the carb mounts to the intake manifold. I'll start watching that closer and start using a straight edge.
When you have the shroud off running the engine watch into the cab intake, sometimes you can see which cylinder side of the two barrel carb is spitting back if it's a carbon or intake valve issue. (the two sides of the carb are isolated from each other. I've actually seen one side of them carbs completely dead, engine only running on one cylinder, give it a squirt of fuel into the carb throat on the dead side and momentarily get a live cylinder. This is not your problem, I'm just indicating that them carbs can really be a brain teaser with some of their issues)

 

[Poodlehead]

Well I pulled the shroud off, fired it up and listened closer. I think the occasional cough is actually coming out the exhaust, not through the carb. Spraying carb cleaner around the joints while the motor was running didn't change anything, so I don't think I have any air leaks.

The coils gaps are about a business card thickness gap,which I'm thinking is ok.

I think my next step will be to remove that damn Swish Plate and see what happens...

I've looked at many YouTube vids and that's where I found out about the plastic intake bowing and did confirm mine was bowed/leaking.

I did take a couple pics showing the air gap using a blue straight edge and the bows at each end of the captured nuts on the intake.

 

[Poodlehead]

Might have to just run it awhile under load

I think that must have been it...

Before I removed the swirl plate, I fired it up one last time this morning and to my surprise, it seemed to run much better! I put the cover with air cleaner on it, mowed for over an hour, ran great, and no coughs!

Thank you all for your help!

 

[Forest#2]

I had not read your post #34 carefully.
Some good info in your post #34 link about the swirl plate.
The service bulletin mentioned in your link indicates the swirl plate for black smoke at some temps due to the fuel not atomizing correctly. (some of the carb engines did not use it) I've noticed that the carb throttle plates will sometimes hang up on a swirl plate if it's not aligned properly as the bolts are tightened.
Keep a heads up that a paper gasket is needed on each side of the eyebrow swirl plate.
I try to stay away from ethanol gas especially when a dual throat Nikki is involved. I also install a white inline fuel filter just before the fuel pump. White type is usually a finer filter for use with fuel pump vs the red coarser filter that is for gravity feed (no fuel pump)

Keep in mind what I told you in a previous post about quite often when a Dual throat Nikki has been running good and all at once instead of removing the carb for cleaning try removing the 3 screw top plate and use low pressure air directed at the slit channels in the very top of the carb under the plate. If you do not have access to a air compressor 20 lb air just try canned carb cleaner pressure. Blow nozzle from air compressor is best.
Be careful of bowl gas spewing upward towards your eyes. This is flushing the tiny jet slits down into the carb bowl and towards the carb throat.