B & S V-Twin 656cc Hunting

[Diwali]

My JD X127 engine, B & S V-Twin 656cc, model 40N8770072B5 runs but is continuously hunting After removing the air filter and spraying the intake with carb spray the engine runs smoothly for a few seconds and then starts hunting again. Same happens when a little choke is applied. If I rev up the engine holding the governor lever it runs fine but when released it is hunting again.
Checked and cleaned plugs; replaced the fuel filter and checked fuel pump flow. I'm a bit hesitant to tackle the carb - the machine is less than 2 years old. But now at a loss as to the next steps to solve this.
All suggestions gratefully received!

 

[Auto Doc's]

The carburetor bowl should not be too difficult to get off to see if it has any rust or water droplets in it. A carburetor will not suck in water droplets, but it will interfere with proper fuel flow into the main jet.

A fuel can that sits open will collect moisture from the air.

 

[Diwali]

The carburetor bowl should not be too difficult to get off to see if it has any rust or water droplets in it. A carburetor will not suck in water droplets, but it will interfere with proper fuel flow into the main jet.

A fuel can that sits open will collect moisture from the air.

Thanks. Removing the carb bowl turned out to be a bigger job than expected…. and, after cleaning, it didn’t fix the problem! I should have done a full carb service while it was in pieces.

 

[Auto Doc's]

Hi Diwali,

Sometimes it's a matter of trying the simple approach first.

Yes, most likely the carburetor will need some disassembly to access the fine passages that are clogged. Do not remove the plate with screws because it will have to be recentered if messed with.

Here is a parts link that may help:

PartsTree - Home of OEM Parts for Outdoor Power Equipment

Parts lookup and repair parts diagrams for outdoor equipment like Toro mowers, Cub Cadet tractors, Husqvarna chainsaws, Echo trimmers, Briggs engines, etc.

www.partstree.com