Robin revs up and down? Please help!

[ThatGuyYouKnow]

Okay guys ive been fighting with this for months. I have a robin ex13 generator that constantly surges with or without load. I cant find out whats causing it. Ive replaced the carb which cant be adjusted. Its got new plug, timing is set, freash gas. It runs pretty good fully choked but as soon as you remove or even try half choke it revs up for a sec and then surges down. Please help.

 

[bertsmobile1]

Surging on a governed engine is nearly always lean fuel .
So the next trick is to heavily spray around the inlet with some WD 40 or sililar from A TRIGGER PACK.
You are looking for an air leak which will suck in the WD 40 and cause white smoke & the engine to change speed.
Second trick is to check the fuel supply is aequate.
If the engine starts uo OK and runs a minute or so then starts to hunt that generally shows the fuel line is blocked .
And don't forget the filter inside the tank.

 

[ThatGuyYouKnow]

Ill try that. The tank has no filter and the inline filter is new.

 

[ThatGuyYouKnow]

Okay tried wd40 around the spark plug and carb gaskets with no change. I also tried spraying gas directly through the air base and the engine would just try to die. But after trying the 2 previous i will now run 5 to 6 seconds before roughly idling down then back up. Any suggestions

 

[reynoldston]

Carburetor problem, surging is something wrong in the low speed circuit of the carburetor.

 

[ThatGuyYouKnow]

Tomorrow im going to dump in some seafoam and let it run for a hour or so and see.

 

[reynoldston]

Tomorrow im going to dump in some seafoam and let it run for a hour or so and see.

The best of luck with the Sea Foam. Just never a believer in additives but hope the best for you. As I said its in the low speed circuit in the carburetor and if your carb has a low speed air adjustment you might have better luck adjusting that after you try the seafoam if the seafoam doesn't fix it.

 

[BlazNT]

Seafoam is just really really really clean kerosene.

 

[ThatGuyYouKnow]

Sadly unlike the original carb the replacement carbs for the robin ex13 have no adjustments on them. Trust me ive looked everywhere on this carb and it has no adjustments.

 

[ILENGINE]

Try holding the throttle in one position and prevent the surging and see how it runs. If it sputters or tries to die then you have a fuel problem. If it runs steady without sputtering and rough running then the problem would be in the governor.