One jet fell out of the pickup tube

[Forest#2]

Poodlehead.

Did you get the Nikki to fly high and smooth?

 

[Poodlehead]

Did you get the Nikki to fly high and smooth?

I got it started, but it's stumbling like it's real lean and won't idle... I got to thinking about it and think I know what the problem is...

When I installed the big O-ring in the pickup tube, I think I pushed it too far in the pickup tube so the O-ring partially blocks the jets...

Not positive, but hopefully I'll get out there tomorrow to see if that's the problem...

Looking forward to cooler weather

 

[Forest#2]

I got it started, but it's stumbling like it's real lean and won't idle... I got to thinking about it and think I know what the problem is...

When I installed the big O-ring in the pickup tube, I think I pushed it too far in the pickup tube so the O-ring partially blocks the jets...

Not positive, but hopefully I'll get out there tomorrow to see if that's the problem...

Looking forward to cooler weather

If you watch the video I sent the big o ring is suppose to be on the raised portion in the bowl instead of the pickup tube and it seats itself into the pickup tube as the bowl is installed. (this is casually mentioned at about 5:40-6:00 of the first part of the video when he pulls off the bowl) Apply just a light smear of vaseline to the o ring. Make sure it's not mashed or distorted. I doubt if this o ring is what is causing your issue unless the o ring got push up against a jet. It seals the bottom of the emulsion tube so as the solenoid shuts off all gas to the jets when the 12v is removed and pevents a backfire

If it does not idle good after you check the large o ring. Review the Nikki carb two barrel Idle circuit at this link. Note #12 in part 2. This is for the steel bowl but your idle circuit is the same. These idle circuits need cleaned. What I have done to get a good run W/O removing the carb fram a engine is remove the 3 screws from the top plate and take low pressure air 25 pounds and not direct inject into the holes under the plate, just blow air across the channels (use eye protection because this also will blow gas up out of the bowl) You can easily make the flat gasket for the top plate or turn it upside down if not torn and lightly smear vaseline across the dry hard gasket and re-install. This quite often clears the idle jet circuit. If this don't work use a tag wire and clean the idle jets hole from the top with the carb off and with the bowl removed you can see light through the jet holes at #12 blue and #5 by looking at a light on the bowl side. Also I make flat gaskets (gasket material from a automotive) for the intake to head where the O rings are. The double the gaskets so as they are about 3/32-1/8 inch thick.
The old o-rings sometimes do not seal good for re-use and the later kits sometimes includes the 1/8 inch thick flat gaskets.
Link to carb repairs: See the Nikki 2 barrel types and review part 1 and 2.

https://outdoorpowerinfo.com/repairs/

 

[Johner]

Once had a problem finding very small O-rings. Had the right size fuel line, cut 2 peaces the thickness of the O-ring and used them for my for the repair. Had a pic. how I did it but can not find the picture.

 

[Poodlehead]

Once had a problem finding very small O-rings. Had the right size fuel line, cut 2 peaces the thickness of the O-ring and used them for my for the repair...

I was able to easily find those o-rings this time, but that's a good idea about making them IF you have the right size line... That's worth remembering, thanks!

 

[Forest#2]

Edited post #23 about the o ring you mentioned.

 

[Poodlehead]

Edited post #23 about the o ring you mentioned.

Thank you! The carb is still on the mower so in addition to Vaseline, I pushed the bigger o-ring up in there to make sure the jets didn't fall out. I shouldn't have done that...

That is a great video and if I have to pull off the carb, I'll definitely follow that vid and your suggestions very closely.

Thank you again! I'll update once I do something...

 

[Poodlehead]

Well the O-ring pushed too far up in the pickup tube wasn't the problem. It still runs like crap, even above idle, like it's not getting enough fuel. I'll try removing the top plate and blow low air pressure through the idle circuit, but not expecting it to fix the problem. Hopefully I'll be wrong

Will update when I've done something . Thanks!

 

[Forest#2]

Look at the pictures at outdoor link of the jet holes under the top plate.
When the carb is off the engine and the bowl off the carb you can see light through two of the holes looking towards the bowl.
On the other end of the channels from the jet holes is just small slits and a tag wire will not go through them. They come out inside the carb throat behind the throttle butterfly. You can also use the spray can carb cleaner in this area when the carb is off. If either side of these is restricted the carb will be upset both high and low.
The flat gasket under the plate must seal good when re-installed. If it's deeply compressed I turn it upside down or make another one then coat it with grease to soften the dried gasket.

Wear eye protection at all times when trying to clean the jet holes.

 

[Forest#2]

You may know this. (just mentioning another Nikki thing for this type carb)

Seems little strange that the large o ring is in the bottom of the plastic pickup tube when you pull the bowl. (it's quite common to see the o ring stay in the emulsion tube when the bowl is first removed instead of remaining in the bowl for re-assembly.)
The o ring should be in the bowl when installing the bowl because if it's in the pickup tube under the jets it can get pushed up too high by the bowl casting and upset the Nikki jets fuel intake.