Briggs Opposed Twin 20hp Surging

[davbell22602]

I guess the only thing left to do is to replace the carb since theres no fuel/air mixture screw to adjust.

 

[slomo]

Either your carb is dirty, missing parts inside or not adjusted proper in the linkage dept.

Boil clean the carb prior to buying a Chinese carb. Open it up and make sure you have all the parts required inside.

 

[davbell22602]

I already cooked it for a hour in a heated ultrasonic cleaner. This is the nikki version not the walbro. Only adjustment is the idle screw. Rebuild kits dont come with a new seat. Seat isnt removeable.

 

[slomo]

I already cooked it for a hour in a heated ultrasonic cleaner. This is the nikki version not the walbro. Only adjustment is the idle screw. Rebuild kits dont come with a new seat. Seat isnt removeable.

Those ultrasonics are not the end all of carb cleaning. You have to do it maybe 3-5 times and if then get a good clean on one.

At most those ultrasonics are for jewelry and trinkets. Most ultrasonics take the entire cooking time just to heat the water up.

Boil the carb on the stove or in a yard sale crockpot. Run at 200F for 40 mins using a dishwasher soap pod.

 

[davbell22602]

I find that hard to believe about ultrasonic cleaners. I know experienced shops that been in business for over 30 years that use them everyday with success. Dont have a working stove or crock pot. Im just gonna replace it. Thanks for the help.

 

[slomo]

I find that hard to believe about ultrasonic cleaners. I know experienced shops that been in business for over 30 years that use them everyday with success. Dont have a working stove or crock pot. Im just gonna replace it. Thanks for the help.

Watch videos of other people using them on carbs. They state you have to recook several times. Better tools out there that offer instant heat and are much cheaper if not free. Keep using an ultra cleaner. Doesn't seem to be working for you. Good luck with it.

 

[sgkent]

I might consider putting a tachometer on it and see what the RPM actually is at the top speed. The half choke can be making it richer, or it can be slowing the engine just enough to stabilize the governor system from oscillating.

 

[davbell22602]

I might consider putting a tachometer on it and see what the RPM actually is at the top speed. The half choke can be making it richer, or it can be slowing the engine just enough to stabilize the governor system from oscillating.

top speed with half choke is 32xx. With no choke when surging is 2800 to 3100

 

[CraigH]

Have you tried holding the governor manually to check that it's not a weak spring on it allowing it to move?
When you say surging, is the engine hunting or a slow surge up/down in revs?

 

[davbell22602]

New carb fixed the issue. Thanks for the help.