[smoe]

My 316 Onan B43E started surging wildly regardless of throttle position. There are plenty of previous posts that suggest intake manifold air leak, carb idle jet plugged or governor issues.

I thought I would out-smart the dang thing by replacing the intake manifold and carburetor with a set up that I believe to be running fine when they were taken off a 318. Put it all back together and same surging problem.

I figure it must be a problem with the governor. Pulled the motor then the timing case expecting to find the little ball bearing at the bottom of the governor shaft to be missing or stuck or the plastic spider-shaped gear loose and spinning on the cam shaft but no! Everything seems nice and tight. The fly balls are all good. The spider gear (metal) is firmly attached to the cam shaft. The cap that fits over the fly balls slides freely on the shaft. I'm stumped.

I got me some new seals and gaskets but before I put the timing cover back together, I want to know, is there something else I need to check?

Perhaps I have carburetor/ intake problems with the replacement ones as well. what's the odds?

 

[jlang]

Boomer? might have a clue for you!

 

[knottyrope]

is it over revving? if yes then the plastic spider wheel will slip when hot, not when cold

if just surging then its usually the idle jet is plugged up

 

[smoe]

It does not over-rev. It just persistantly surges regardless of throttle position.
The spider gear is metal and it seems quite firmly attached.

 

[knottyrope]

does it run better when choke pulled out? if yes then most likely a fuel issue. Check he idle jet for a clog and sediment in the bowl

 

[mikeduwe]

Did you try resetting the governor? How about moving the spring to different holes, if available (not sure on onans).

Does it go away when you load it down?

 

[smoe]

While putting the flywheel back on, I snapped off the bolt inside the crank. Might be a while now because I don't have an extractor that will go in the bolt hole 3" to reach the broken portion. I don't suppose someone has experience with this little blunder?

 

[Hammerdown-7]

Hello Steve
I restored my 1983 John Deere 318 a couple of year's ago and placed a new Onan P-218 engine in it. Shortly there after it began to surge badly and would only run with the choke Pulled on fully, and even then it surged some. I traced back and sealed the intake halves and it still ran the same. I Pulled the top off of the carburetor and did not see anything that may be causing the surge so I spent there tedious days looking for the cause of the surge attempting to adjust the governor and that did not cure it either. I replaced the Intake to engine gaskets and it did not help either. I finally Pulled the Carburetor jet and made sure all of the side tube tiny holes were open and clear of which they were. I then Noticed a slight chamfer on the bottom of the Idle jet tube, which told me it had to be a metering hole for gas so I Pushed a gas torch tip cleaner down through the Idle jet tube and a Tiny Piece of rubber fuel line was the culprit causing all of my surging issues. I read & read on surging issues and no where did I see anything about the Idle jet tube having a Main hole down through the entire tube not even in the Onan service manual. The Tube has to have the Main hole clear for the engine to run right and I was surprised to see that it even supplies the Upper RPM range in the Tractor with the metering of correct fuel. I had replaced all of the Old gas Lines during the restoration process and evidently I managed to get a Tiny piece of the old broken down gas line into the fuel delivery system and it Plugged the Idle jet tube. I would Pull that jet and inspect it closely to make sure it's main hole down through it is clear as well as all of the side tube tiny holes I used a small sewing needle to clear all of them. I hope this helps, Kurt