Nikki carburators

da.bees

Well-known Member
It seem's that Nikki carbs on B&S don't work long after cleaning. Surgeing/hunting like poorly adjusted governor is the most prevalent. I've increased size of jets,installed filter with new hose between carb and filter,Seafoam and non-ethanol.
I've realized for a number of years that air cooled engines can have fuel problems but Nikki carbs are giving me fits. Are there options for changing to a different type carb or is that even necessary? On the other hand I might be getting less patient in my old age and problems have become like Brylcream.
Something I occasionally see in random carbs is something in bowl that look's like sand in color and texture but actually not gritty at all. Is it possible ethanol is leaching something out of plastic fuel tanks? Maybe it is in solution when passing through filter and sink's in bowl because it's heavier than gas.
 
a lot of times the surge hunting is air leak at gasket , does it smooth out under load or when you move choke. if so the its starving for fuel usually,gasohol has nothing to do with it I have used since first came around to today in all my small engines ands as of yet had any engine issues . sounds to me like you getting dirt in, ran small engine shop here for over twelve years. keep it simple do you have full flow fuel out of tank first their is screens in them
 
IF....this is the carb on a twin Intec engine, they get out of balance
internally. Ethanol raises heck with them. I have covered this several times on
here and this is what I do. Go on Ebay and buy a new carb. Best $28 bucks you
will ever spend. Have done three machines and they work just super. Take you
maybe an hour or so to change it out. Just make sure you put that little mixer
plate modification the correct way around. My opinion-it is mine- and I will
stick to it. Now if it is a single cylinder engine I would still replace the
carb. That spiderweb seal in them goes bad. Also the stupid jets fall out.
Other guys will have other opinions but the replacement carbs work wonders. I
run all of my small engines on hi-test gas and you want a set of NGK BPR6ES
sparkplugs.
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I think it's entirely possible that the fuels we use combines with whatever plastic the tank is made of and creates problems. I also think Nikki carbs, most inexpensive carbs these days for that matter, are just that- cheap carbs. The days of the old reliable Briggs running for 10-15 year w/o so much as a whimper are gone. It's a throwaway society. Stubborn guys like us are the only ones that even wonder why things stop working. Add in ethanol and the problem grows exponentially.
 
We run E-10 in all of our 4-stroke engines with no problem, the ethanol keeps them clean! We have a couple of push mowers over 15 years
old, no problems, no repairs, start the first pull in the spring! Plastic gas tanks are one of the greatest improvements to small machines
in history.
 
In some cases engine does indeed smooth out some under load and cleaning jets often restore's idle quality but another problem often occurr's before long. Ethanol has been cussed, discussed and defended for years without comeing to conclusion everyone believes. I'm sure alcohol cause's it share of problems but I still have problems when using non-ethanol so I believe there's also lack of durability in carburetors. Thanks for the replies.
 
Since you don't say which Nikki carburetor you have trouble with, I have to guess its a two barrel on a Briggs twin engine. When you
clean it, do you also clean the jets in the body itself? They are the little brass pieces in the passage between the float bowl and the
large cover on the top of the carburetor.

Also be sure to blow back through the gas inlet elbow. Any trash left there will go right in the carburetor when you put the fuel line
back on.

like the other guys said, a deteriorating fuel line can fill a newly cleaned carburetor with trash in short order.

Actually, in my experience, they don't give any more trouble than other carburetors, just different trouble. Like the steel float bowl on
Walbro carburetors tends to rust if there is moisture in the carburetor. Then the rust causes problems. Also, on some Walbro carburetors,
its difficult to clean the idle circuit. You have to just soak it and hope for the best.
 
(quoted from post at 11:34:41 10/06/19) Since you don't say which Nikki carburetor you have trouble with, I have to guess its a two barrel on a Briggs twin engine. When you
clean it, do you also clean the jets in the body itself? They are the little brass pieces in the passage between the float bowl and the
large cover on the top of the carburetor.

Also be sure to blow back through the gas inlet elbow. Any trash left there will go right in the carburetor when you put the fuel line
back on.

[b:91effb9c23]like the other guys said, a deteriorating fuel line can fill a newly cleaned carburetor with trash in short order. [/b:91effb9c23]

Actually, in my experience, they don't give any more trouble than other carburetors, just different trouble. Like the steel float bowl on
Walbro carburetors tends to rust if there is moisture in the carburetor. Then the rust causes problems. Also, on some Walbro carburetors,
its difficult to clean the idle circuit. You have to just soak it and hope for the best.
As pointed out in original post "new line from new filter to carb" eliminate's that possibility.
 
(quoted from post at 19:35:07 10/06/19) Nikki carbs are junk. I don't waste my time trying to make them work. toss it and buy a new one.
I've about come to that same conclusion and hoping to find an interchange rather than buy another piece of junk to replace the junk I have already.
 
I recently purchased a machine with the BS 206, 5.5 HP engine. I noticed that the Nylon rt. angle adapter, where the fuel enters the carb was cracked causing a fuel leak. Looking to see if I could repair the interface myself didn't look doable. Got on my favorite ebay and found the exact carb in your top picture for right at $12.50 with free fast shipping from California. Got it yesterday and it took me about an hour to install it and get the choke lever and all matched up. Took the pinch off the gas line letting the bowl fill up, flipped the lever over to full choke, set the throttle to mid position, gave the starting rope a good pull and wala......lit right off.

No way can you fool with existing problems when you can get new for this kind of money. Yes we are a throwaway society and I love it......spoken by a guy that used to repair TVs as a sideline back in the early '60's.....remember those were the days when RCA came out with the magnetically focused 3 electron gun color TVs..........need I say more.....red, blue, or green edges to white collars you get it fixed in the center of the screen and it's out on a corner or two....grrrrrrrrr; customer wifie runs the vacuum cleaner by the TV and all of a sudden your red raster has a big blue smudge in it....on and on.....fix the TV in the shop facing South and delivery guy takes it to the owner's house and it sits East.....convergence, that you spent an hour trying to get right is out, absolutely must be degaussed any time you move it anywhere...on and on.
 

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