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18.5 HP Briggs

#1

D

digr

Runs not the best at full throttle but good enough ti get the job done, at idle it seems to run out of gas until the governor kicks in and keeps repeating. Is this carb adjustable?


#2

I

ILENGINE

You will need to help us out getting us the model, type and code from the engine so we know if this is a 33xxxxx series or the 38xxxxx series or the 42xxxxx series engines.


#3

B

Bertrrr

Not sure these new carbs can be adjusted other than idle speed , Probably need to pull it and clean it good , might have some debris in the bowl or jets


#4

F

Forest#2

If it's a Overhead valve type Briggs get the engine info from the top of a valve cover.


#5

D

digr

I will get the number after I get the lawn mowed, still have a acre left, I didn't want to monkey with it until I was done.


#6

F

Forest#2

I will get the number after I get the lawn mowed, still have a acre left, I didn't want to monkey with it until I was done.
You do not have to remove the valve cover to get the info, UNLESS some Bubba installed the cover upside down. If a twin Bfiggs it's usually on the top of the right side valve cover (as you are setting in the seat looking forward)
Be sure to get all correct when posting. Sometimes a 3 is a 8 etc due to weak stamping into the metal. After you get the ID model, type, code you can go to the computer and type the info in and add parts at the end in the search bar and if the info is not correct the computer will tell you to try again with correct info. this saves us a waste of time browsing with wrong info.


#7

D

digr

Model 31Q777
Type 0466E1
Code 050114ZD


#8

F

Forest#2

You will get some replies now that you have posted the ID info.

Here is a link to IPL parts list for your engine.
It came out with 3 different carbs, the Walbro which is NLA was the better one. Yours is most likely the Nikki.
If yours is a Nikki try to save it rather than using the cheap China clone replacement at $20 or less.
You can find lots of repair info on-line search for your carb. (once your know which one you have) assuming your is carb issues.
Here is one link as a starter that will show most all carbs except the Ruxing type.
https://outdoorpowerinfo.com/repairs/


#9

D

digr

I took the carb off and cleaned it now it won't run at hi speed , it floods I think it is the high speed jet that was laying on the carb when I lifted the float housing off. I assumed it went into the float housing with the O ring toward the bottom of the float housing, I will take it apart again and see if the jet flipped when I dropped it into the float housing.

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#10

F

Forest#2

That jet is going to need a NEW o ring. What you seen is a sign that the carb wants a kit. (might as well knuckle down and do such.
Here is some info for you to review. Also note that the rubber gasket ABOUT the emulsion tube MUST BE ingood shape and not leak. It will let gas in and appear as though the needle and seat is leaking when it does not seal.
You can find lots of info on line about how to remove, install kit etc using a Nikki one barrel carb. Keep a heads up and don't break the plastic on top of the carb throttle plate when removing or installing.

Here is some info



Nikki Briggs one Barrel carb rebuild tip, you tube.



This is the carb used on single cylinder Briggs engines in place of the Walbro LMT. The NLA Walbro LMT is the better user friendly carb.

You tube link

Nikki Carb Rebuild Single Cylinder Briggs - YouTube



Also see

https://outdoorpowerinfo.com/repairs/

Small Engine, Lawn Mower, Snowthrower Troubleshooting, Repairs and Safety (outdoorpowerinfo.com)


#11

D

digr

Thank's all for all the help it is running mighty fine again!!!! I took it apart again and made sure everything was as it should be and it fired right up.


#12

F

Freddie21

I have found cheap Nikki replacements and install them in place of the Walbro. They work much better. May just have to ream the opening in the intake plastic tube cuz the choke may drag. I don't use the Walbro any longer


#13

J

Joe657

Runs not the best at full throttle but good enough ti get the job done, at idle it seems to run out of gas until the governor kicks in and keeps repeating. Is this carb adjustable?
Sounds like a poorly adjusted, dirty or damaged governor. If you can get direct access to the throttle on the carburetor, try holding it a little bit above idle to prevent the governor from moving it. If it won't hold a steady rpm, the carb could use a good internal cleaning. A good (no disassembly required) carb cleaner/gum remover/stabilizer is and additive called, Startron. It comes in 8 and 16 oz. plastic bottles found in Walmart automotive and other places where engine/automotive additives are sold. 8 oz. is good for 50 gallons, but I would double the concentration initially on a poorly performing engine. It may take many hours to completely clean out the gunk, but you should see positive changes in performance in an hour or less if a dirty, gummed up carb is the issue. Also check to see if the throttle assembly is sticky or slow moving: clean as necessary with carb cleaner/de-greaser.


#14

J

jviews12

IMPROVEMENT: add cuttoff valve, and run dry when putting away even for a few days. I assume you have a gas filter also already in-place.


#15

D

digr

Thinking of putting new rings in this engine this winter. Any suggestions?


#16

F

Freddie21

Before doing a ring job, check the easier items. Valve and guides, head gasket and all other gaskets, clean the carb and replace all filters.


#17

D

digr

Head gasket is fine, just cleaned the carb and filters. It has been a smoker for two years now.


#18

F

Freddie21

Valves, guides and breather. Just trying to save an engine tear down.


#19

F

Forest#2

Thinking of putting new rings in this engine this winter. Any suggestions?
Couple tips to condsider
When ordering parts like rings pay attention to the CODE ID.
Briggs changes parts numbers going by the code on lots of their engines, especially the OHV type.(including the rings parts numbers.
I've used rings from little red barn that sells on amazon with good results at usually around $40 per set for ONE piston and I've also used the $20-25 gasket kits with good results but for the sump gasket I use light coating of Yamaha bond 4 and clean the sump/block surfaces really good and I let the yamaha bond cure for at least 12 hours before adding oil. I also pay attention to the head gasket torque sequence. I also sometimes get the really good head gasket instead of using the flimsy kit type head gasket because you engine type is know for head gasket issues at the oil galley area.
I run leak down tests BEFORE deciding on rings and then if it indicates it's possibly the rings I take the head off and inspect the bore. I do a thourgh inspection BEFORE ordering parts, including removing the rod/piston.
Some of the rod cap bolts on some of the Briggs engines REQUIRES really good quality wrenches. If you round off the head on a rod cap bolt you are going to have a set back delay. I've had to take high speed carbide cutters and grind off a rod cap bolt's head to get the cap off and then remove the stud after the rod is out of the engine. This usually happens when the bolts are the 5/16 head type instead of the torx.


#20

D

digr

Valves, guides and breather. Just trying to save an engine tear down.
How is the breather checked?


#21

F

Freddie21

I don't have your engine info, but some are just a rubber tube from the engine, or valve cover, to the air cleaner housing. Other have a plate, with the tube, mounted to the engine that can be removed. Under the plate is a rubber diaphragm that should be cleaned and its functionality checked. On this type, I would replace the diaphragm and the tube if necessary. I'm thinking that if this is bad, it may cause back pressure in the engine.


#22

J

jviews12

compression test results? remove both plugs, choke off, throttle wide open, then get me a reading.


#23

dawgn86

dawgn86

I took the carb off and cleaned it now it won't run at hi speed , it floods I think it is the high speed jet that was laying on the carb when I lifted the float housing off. I assumed it went into the float housing with the O ring toward the bottom of the float housing, I will take it apart again and see if the jet flipped when I dropped it into the float housing.
my 22hp Briggs carb has two of those jets. They are different size and have to be installed in the right spot.I replaced mine earlier this summer and engine runs like new for being 10 years old.


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