Shotgunning Nikki on Briggs Intek 33" / Gravity

[hanz63]

Some of these have that nasty hunt when first started, then they warm and life is fine. I always thought there was a head redesign or something. 2 years ago I threw my hands in the air and put a new carb on this lady's rider because no matter what I did, nothing fixed the constant hunt. Gov adjustment, nil. Valve lash, no help. The rider was 2 years old at that time. So today the process repeated itself. Real light dirt found at the little round seal at the inlet is all I found. The passage that heads north which I assume is a low speed behind the welsh plug to the adjustment screw passes some air and cleaner, but not much. It does not run much better under load, so what am I looking at here? Her fuel and air is clean. Honestly once again, I put a carb on to get her cutting and out the door for the 4th. Runs better than new. Any Nikki masters have advice on why every two years this happens? By the way Happy Independence Day for all who observe!

[KE4AVB]

Never really had any problems with these carbs here other the aftermarket one that I had to resize the high idle jet. Darn thing would surge at idle and high idle. The original was surging but I wasn't the shop that sold the mower so I sent it back for a good cleaning. Now the air bleeds will clog over time.

And here it all the time that Nikki carbs are junk and how hard they to repair but I found them fairly straight forward to rework. I just run them all through my USC with soap and water. Also pay attention to those jets tiny o-rings as they get loose and needs replacing. I use the Kawasaki Nikki jet o-rings as I can get them in packs of five. Briggs wants us to buy the whole jet. Basically when you have carburetor problems with these that been working fine you clean the carb and replace all the rubber parts.

I even had one engine that was sneezing with a Nikki but that wasn't the carburetor instead it was an intake o-ring air leak. I describe it as a sneezing attack as it was not a full blown backfire instead sounds like someone quietly sneezing.

[Arkie]

Not a Nikki Master here. They seem to Master over me.

Just some things I've seen about Nikki's hunting/surging/spitting.
When working on one for myself trying to avoid spending big bucks for a NEW OEM carb.
If I was working one equipment for a customer they would have the choice of buying a NEW OEM Nikki (some replacements at over $200) or going somewhere else, because they are most generally themselves the cause of the bad carb due to poor TLC with fuel and their equipment.
For my own use When I find one of the dual throat Nikki's for a twin cylinder engine hunting I can usually just use a can of carb cleaner with the small nozzle and blow out the jet holes and replace the emulsion tube jet o-rings if the o-rings are not snug fitting. If the inside is really nasty they go to the Usonic first I've found GENERIC China clone kits for the dual throat Nikki's for around $15 that have all the o-rings although not all the Nikki's are the same inside. (one size does not fit all even though they look the same on the outside)
Most generally if I give one a good cleaning Only both the single cylinder type and the dual throat type and put one back together and it still surges I have to go back and replace the o-rings associated with the emulsion tube area, especially if the emulsion tube has the two itty bitty jets.
I recently bought a $20 china clone dual throat Nikki to replace a OEM surging Nikki I had cleaned and did not have a kit and the NEW China clone was surging worse. After re-checking the intake and all else I removed the CHINA Nikki clone bowl and seen that the emulsion tube was same as the OEM, so I used the clone emulsion tube and associated parts for parts into the OEM and got a good run.

I suspect that most generally PEOPLE are using the somewhat[b][color=#0040FF] LOWER PRICED ethanol fuel and causing lots of the carb problems even the Nikki o-rings going bad faster than normal.[/color][/b] (and at $5 plus/gallon for non-ethanol fuel now days most people are going to use the somewhat lesser priced ethanol fuel which weakens/hardens fuel lines and o-rings and makes moisture and the majority of the China Clone carbs will rust inside the bowls very fast even with good fuel.)

I always try to use non-ethanol fuel and external in-line fuel filters and do not have very many carb issues unless the equipment is left un-used for long time without a fuel stabilizer. I sometimes seen lawn tractors that have a large style fuel cap that the top of the cap will trap/puddle rainwater and the gas tank fuel will eventually get contaminated with moisture. (gas tank vent in the cap will eventually take in little bit of the water from the top of the cap)

[hanz63]

Thanks for your thoughts. I don't think this single has a removable tube. Wonder if the plastic float body on these warp? I'm pretty lucky on the twins, but I share your "fondness" for the knock off carbs. The twins I pretty much just buy the seals by the piece, never thought of the knock off kits.

[Arkie]

Here is a link that I use sometimes when into small engine carbs.
Just scroll down until you see the carb in question or go to the engine type and look at carb in question as to make of carb usied on the engine Walbro/Nikki, etc..

If you know the engine just make the carb is used on scroll all the way down and choose the engine carb, for example a Kohler with a Nikki carb.

This is the repair index page link. click on HOME page for other types of info.
https://outdoorpowerinfo.com/engine_specs/