[jd1979212]

I have a John Deere 316 with the P218 engine in it which would make it a 1988.

My problem is as soon as I start the tractor up it starts surging but when I pull the choke out a little it levels off.

It has an almost new fuel filter.

Would it just be a simple carburetor adjustment?

I am not very good with the Onan engines and the carburetor looks complicated so I might need a diagram.

Ben

 

[chuckv]

Ben,

Surging at low speed is due to too little fuel through the low speed jet (debris or 'gelled' ethanol/water from 10% or higher ethanol content fuel) or too much air entering the manifold below the throttle plate. The latter can come from a failed seal in the split style Onan manifold, a bad manifold gasket, or a worn throttle shaft bushing. The search engine on this site will give you lots of threads discussing these with plenty of pictures. Use the "Search" button on the yellow bar just above the beginning of this thread and set the criteria to "Onan surge" -- be sure to set the case to any, whole words and 'and' rather than 'or'...

I get about 50 hits for this search with this being representative:
http://www.wfmachines.com/discus/messages/335/256794.html

Happy reading, and let us know what you find.

Chuck

 

[wmgeorge]

If your working on a Carburetor or something complicated like it for the first time, take a couple pictures with your digital camera for reference.
If you carefully remove the top of the carb and try not to drop any of the screws, there are two jets I recall you can remove and clean. Most of the time its stuff in the bottom of the bowl and it needs cleaned out also. The jets can be cleaned with carb cleaner and a small solvent safe brush. Or if I can find a piece of wire small enough to get inside the hole without making it bigger that works great. Blow out with compressed air.
If that does not do the trick then on the Links suggested. It took two cleanings to get my jets clean.

 

[knottyrope]

also take apart the fuel pump, I had lots of junk in mine and at the 90 inlet on carb.

I eventually removed tank and cleaned it, changed out lines, cleaned pump and bowl. then started to use a lil 2 stroke oil since my dirt bikes never had this issue. I add an oz to every gallon. no more issue with sandy crud in bowl since then.

 

[Hammerdown-7]

Hello Ben
The Idle Jet in these Niki Carburetor's is very common to Plug up. I replaced all of my fuel line's when i restored my 1983 John Deere 318 and some how a small piece of the rubber Internal fuel line got into the Idle jet main hole down through the Center of the Jet and Plugged it up causing it to surge Wildly. I read No where about that Jet having a fuel metering hole down through the center of it, so it took me Three days of frustration locating the surging issue. The small side tube Holes get Plugged up as well. I have Installed two see through gas filter's to eliminate this issue from ever happening again. The fuel pump's get sediment in them so take your's apart and clean it well. be careful when disasembling it to not Loose the small ball behind the diaphram. I used Gum-Out Carburetor cleaner to flush my fuel Pump out it work's really well. I Now have a see through gas filter on the incoming line before it hit's the fuel pump and another one before the gas Hit's the Carburetor. it was the best Ten dollars that I ever spent I have no more trash in my Carburetor or fuel pump issues. I hope this helps, Kurt

 

[trapperjohn]

Ben, I had the same problem and removed these two jets and cleaned them and all is good. Just remember, that junk same from somewhere. If it happens again, I would check out the tank and lines and add a filter.

 

[Hammerdown-7]

Hello Ron & ben
By adding Two large see through gas filter's there is Little worry of any Trash Hitting that tempermental Niki Carburetor. Regards, Kurt