Partman Carburetor for Onan Cummins A041D736, Microquiet 4000-Watt 4KYFA26100 Generators

UPDATE: No leaks, but carb is running a little rich (slight black smoke & strong exhaust smell). Hoping to adjust the mixture to hopefully remedy this.Observed issue: KY 4000 QG RV would not cold start (or hot restart) unless the choke was manipulated closed. Once started, it would run with a slight surge that would fade after 30 min or so. Spark plug indicated a slight rich mixture.Diagnosis: Gen had gone unexercised while in the shop for 1 1/2 months.. Suspected clogged jets due to sitting fuel. Adjusting choke via the bimetal plate did not help. Used Seafoam/gas mixture fed directly from an alternate fuel source (2 gal jug), heat soaked, re-fed, etc. Ran smoother, but would not cold start. Decided to replace carb with this unit.Install: As one of the air assembly adapter brackets (under air filter) had snapped (adjacent to one of the interior retaining bolts), had to use JB Weld epoxy to glue the metal end-piece to keep it from interfering with the choke flap which may have also been occurring. Used a scope camera tool (Amazon item) to more easily use a 10 mm socket wrench to remove the carb retaining bolts. No issues removing the old carb. Did use a small rubber mallet to break carb away from manifold as it was on tightly after bolts removed.The gaskets provided will need to be modified as they are not cut similar to the OEM Cummings ones. I carefully removed the old ones using a box cutter blade & repurposed them to ensure a better seal.To re-insert the air/carb assembly bolts, I used the camera scope (with iPhone screen) to get them in the hole while gently moving the carb to gain proper alignment. If aligned properly, the bolt should noticeably drop all the way through the manifold hole…if not, keep trying. Oh yeah, I used a few dabs of clear sealant to attach the gaskets as they will fall off when putting the carb in place. Apply pressure to the air assembly to give you some space while inserting the new carb…it will give a bit. Ensure choke flap & throttle flap are not impeding insertion of carb - both should be closed. Also insert the choke & throttle rods “before” putting the carb in its final position. The throttle rod has a spring hook attachment, don’t forget that.Once in place, double check your gaskets and tighten down. Reconnect electrical wires & fuel line.Results: primed it for 10 seconds and it started right up in 2-3 secs. Checked for fuel leaks. Ran no-load for 15 min, med load for 15, and heavy load for 10 while checking for fuel leaks or issues. None arose. The original gaskets worked perfectly.Thoughts? Will see how this China-carb holds up over time. Will be installing a fuel shutoff valve to clear the fuel line when the gen is not going to be used. The endoscope camera was invaluable as I was unable to take the gen cover off & used it to remove/insert bolts and check the other side of the carb for alignment & gasket orientation.If this carb proves unreliable, I’ll update the post and just spring for the OEM version. Once the carb gets gunked up, it’s a losing battle. I wouldn’t do the Seafoam enema approach if non-starting issues have arisen…maybe for slight surging.

When purchasing this item, I was originally interested in the gasket material to rebuild the original carb. I had not intention to use the new carb itself. When I got the old one out, it had more junk in it than I liked and I was in a hurry to get it back up and running. I then decided to put in this carb and it started right up and actually runs better! It’s been great for me so far and we are about 12 hours in with no issues.

Previous owner already replaced carb with aftermarket unit, but I did not take care of it and let it sit with old gas. Surging and quitting on the road. My bad.After sticker shock of 10x the cost for an OEM carb, thought this was worth a try.After install, generator ran smoothly and easily took on the load of the AC.Nice little replacement carb. Perhaps I’ll take better care of this one!

The media could not be loaded.  YouTube is awash with videos telling you not to trust these Chinese carbs on Onan generators. So far I’ve been completely satisfied. She runs like new.Installation was fiddly but easily accomplished by any shade tree mechanic. The hardest part was getting the gaskets aligned. Beyond that, take pictures of the linkage before you disassemble and make sure it all looks like the photo when you’re done. Easy.

This is the second aftermarket carb I purchased. Sent a different brand back for flooding. Generator bogs out under any load whatsoever. Eliminated pretty much everything else. These cheap ones are kind of hit and miss whether they will work I am finding but I didn’t want to spend $400 on OEM unless I was positive it was going to solve my problem. One trick I can share to help installation (since I have done it about 10 times) is after removing the air filter and bolts for the carb, replace the air filter cover and tighten the wing nut. This will compress the foam gasket and give some more wiggle room on the carb. Anyway it started without popping through the carb and ran noticeably better. It still bogged out when turning on the breaker. I will maybe try to correct it by adjustment but think I may have an intake leak or possibly even a catalytic converter problem. Glad I didn’t spend the money on OEM at this point but still have to find a problem. Definitely running lean it seems. After all the research in people trying to fix problems I do not have any confidence in Onan any more. This unit is a 2018 with 100 hours on it and hasn’t run since I bought the rv a year ago. When I took the original carb apart to clean it I found not a speck of corrosion or varnish in it. Was spotless and has a filter yet it is clogged? Not sure Onan is using anything better for OEM carbs.