Aftermarket Onan 4000kw carb

[Luke D]

Well after re-installing my rebuilt OEM carb, gen set ran for a few minutes and died. Gas again would not flow into bowl. Needle valve stuck.... yikes. Okay lesson learned. Once bad no matter how clean it looks and how clean you make it. REPLACE. Next 300.00 OEM or Amazon 50.00 ? Bought Amazon. Once again pulled and replaced with Amazon. Now if you ever pulled the 4000KW carb you know what a pain it is. Back carb bolt is a nightmare. Upon getting cheaper Amazon carb you will first notice the difference in weight. Much lighter casting. Most likely a China product. Now the results. Fired right up ran perfect. Ran for over an hour no issue. Ran fine again today. Ok scratching my head. How is this possible???? Maybe I’ll get a shorter life span, who knows. For the price I ordered another. Any thoughts???? Has anyone else done the same???? All I’ve heard is the Onan OEM carb is garbage. Now When stores for now on I added a gas shutoff valve. I let it run dry. I’m sure I’ll still need to clean. But adding sea foam to every tank.

[ducksface]

Lighter casting is possibly due to better machine lathe.
There's no pressure in there worth mentioning so metal isn't really needed except for the gasoline aspects. Tinfoil would work if it'd keep its shape.

If they're making 1600 of them a day and save an ounce each that's 3,000lbs a month.

Tighter tolerances in the castings and machining.

I pretty much trust Chinese casting and machining for the last 10 or so years.
They do get some things wrong because they read the stolen diagram backwards but the work is very tolerance minded.

Oem is stocked in some $2sqft per month warehouse sometimes for years.
Fifteen bucks an hour for the lowest skilled labor imagined... And their supervising staff.

Oem has to be stupid expensive if it's going to take up half a sqft for 15 years.

That mythical $600 government hammer replacement?
It had little to do with the hammer. It had to do with arranging storage and sorting for that hammer on a 30 year plan.

I ordered a carb for the little John deere I just sold.
It was a mirror image of the correct one.
Someone ran the printer backwards, the machinist doesn't know a carb from a bears butt let alone ever saw one. I drilled a hole, swapped the choke shaft for the one I had on the old carb. and it worked.
I really expected that to be the story you'd tell:
Choke was backwards... Throttle hookup upside down....

An aside about Chinese machinists.
Scribes, the ones who copied books before printing, couldn't read.
They had no idea.

[Luke D]

Originally Posted by ducksface

Lighter casting is possibly due to better machine lathe.

There's no pressure in there worth mentioning so metal isn't really needed except for the gasoline aspects. Tinfoil would work if it'd keep its shape.



If they're making 1600 of them a day and save an ounce each that's 3,000lbs a month.



Tighter tolerances in the castings and machining.



I pretty much trust Chinese casting for the last 10 or so years.

Well I’m in so far. At basically 1/5th if the price Amazon is fine. I took the OEM apart again. Float needle valve stuck again. I can free up see no blockage. But if you examine the needle or jet it becomes interesting. The tip is a black rubber substance. I’m assuming nitrile. Hate to assume but I believe it swells and won’t release. I also noticed where it attaches to the plastic float the stem moves in an out. Strange! It would be of interest if you could by new needle valve, preferably all brass, if it would work. Went through several of my old auto carb kits none the same size. Went to the local mower shop they couldn’t match either. I’m keeping the OEM carb who knows. I wanted to post my findings so others can see what I found on the no start issue.

Stay safe