Yamaha ef2800i surging

Seafoam.

I had one and sold it ( hold their value really well). I had to replace the auto throttle motor on mine. It got wonky and surged too. One thing you might try is to disconnect the harness from the top of the carb that goes to the brain box, rake out the air cleaner element and baffle and open the throttle plate manually (use a pencil to hold it open) and start the engine. When it starts immediately release the throttle plate. According to Yamaha that resets the throttle actuator motor. You can download the Workshop manual for the 2800I on Yamaha's website, it's a pretty big PDF. I have it saved here on my computer.

That didn't cure my issue so I replaced the motor (called a stepper motor). Think it was 45 bucks.

Sold mine of Flea-Bay and bought a new Champion and had money left over.

Only reason I sold it was I figured as old as it was, the electronics might poop out so I got a new one. Good Inverter genny though.

That might cure your issue but then again, might not but worth a shot.

gbopp wrote:
Seafoam.

That won't help the surge issue. Might clean out the carb though.

99% of all small engine surge problems are dirt/debris typically in the idle circuit. If you turn off the automatic throttle control and it is still surging, this is highly likely your problem.

Fuel additives MIGHT clear it, but more likely than not the carburetor will have to come off in order to clear all passages. Use a single wire from a steel wire brush.

Have to be extra careful when taking apart the carb on the Yamaha. It's like a Rubic's cube with many little springs inside.

SidecarFlip wrote:
Have to be extra careful when taking apart the carb on the Yamaha. It's like a Rubic's cube with many little springs inside.

This is my concern and reason for posting, want to be careful. I a, expecting the surge issue to be related to a tiny orifice that has a spec of something in it. I believe this bc the Honda gen was surging and it took a decent amount of searching before I found a YouTube that addressed the surge issue on the Honda and it was a carb orifice.

Not sure if this is the prob w the yam or not, it really isn't bad I just know it isn't 100percent.

Most all gasoline motors are much the same. What worked for the Honda may well work the same for the Yahama as far as the carb.

However as others have suggested. Those small engine carbs are... Well be careful when working on 'em.

wa8yxm wrote:
Most all gasoline motors are much the same. What worked for the Honda may well work the same for the Yahama as far as the carb.

More specifically all small engine carburetors are almost identical. There is a main jet and an idle jet. Likely the idle jet is clogged/blocked (the orifice is very small; clean with a single bristle from steel wire brush).

wa8yxm wrote:
However as others have suggested. Those small engine carbs are... Well be careful when working on 'em.

Start with an old 9x13 baking pan or buy a disposable aluminum pan and some spray carb cleaner (make sure it has a straw). Do all your disassembly in the pan. Less likely to lose parts.

External adjustment screws should be carefully screwed in until they bottom WHILE COUNTING THE NUMBER OF TURNS. Then you can remove the adjusting screw, spray cleaner in the passage. Reseat the the screw and back out the same number of turns.

Use spray carb cleaner on all passages but DO NOT get carb cleaner on the bowl gasket (#15). If you do it will swell and reassembly will be difficult (the fix is to washer the bowl gasket with soap and water and then let air dry)

#18 is your main jet. #10 is the idle/pilot jet.




Parts

Surging is nearly always a border line lean condition. And yes a speck of dirt usually in the idle/pilot jet. So start with trying Sea Foam.