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Adjusting carb: B&S 319CC 8hp engine


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05-14-12, 11:56 AM   #1  
Adjusting carb: B&S 319CC 8hp engine

Hello to all...

My Snapper lawn mower has an 8hp B&S engine. Vertical shaft w/electric start.

Accidentally left out in the rain and water got into the carb. Removed and cleaned it but now having issues putting the linkage back.

There are two linkages to the carb. One to the throttle from the governor lever. That one is simple enough.

The other is to the choke and this one has me stumped. One end has a long hook that fits into a slot on the plate holding the speed control cable. When the speed control is pushed forward there is a lever behind this plate that should pull back on the hook and close down on the choke. But it does not. Even fully forward it barely contacts this lever so the choke remains fully open.

The only thing I can think of is the plastic gear (on the back of this plate) has slipped and the metal teeth are not in the correct position... but I cannot see how this could happen. Any thoughts?

Also, there are two adjusting screws. One at the bottom of the bowl and the other at the top of the carb. Can someone explain how to adjust each of them, please?

 
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05-14-12, 01:49 PM   #2  
Hello outdoormike,

It sounds like you need to loosen the throttle cable hold down clamp and slide the cable out, This should give more pull to close the choke.

On the top adjuster lightly close it then open 1.5 turns, Lightly close the bottom then open 2 turns. This will get the engine running, Let it warm for a couple minutes then set the throttle at idle. Adjust the top in or out until the smoothest idle is achieved, Now move to full throttle and adjust the bottom in or out until the engine runs the smoothest without hunting.


Good Luck

 
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05-15-12, 06:19 AM   #3  
It sounds like you need to loosen the throttle cable hold down clamp and slide the cable out, This should give more pull to close the choke.

Should the cable close the choke little by little as you move it forward or only a final shut off when it is pushed all the way towards fast?

Thanks for the help!

 
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05-15-12, 09:13 AM   #4  
Put the control handle in fast position as far as it will move, With clamp loosened pull out on the cable housing until the choke fully closes then tighten the clamp. The choke is applied with the throttle control past the fast position.....

 
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05-22-12, 06:29 AM   #5  
I purchased the complete carburetor overhaul kit from B&S and installed everything as new. Carburetor seems to work just fine.

My new issue is with the governor.

It does not seem to be adjusted correctly. The engine needs to be set way high when I engage the blades and/or the clutch or it loses power. Same when running forward. Stopping and it revs way too high. This was never the case.

Here is a picture from the side of the linkage plate. Can you tell me if this spring is connected correctly. One side to the throttle lever arm and the other to the governor arm.

Name:  spring.jpg
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When I run the engine there is a strong "pull" on the governor arm towards closing off the throttle (towards idle) and this is not there with the engine off. I assume this means the governor is working or trying to work. I did not loosen this arm from the shaft. It is set as it was prior to my starting the repair.

There just does not seem to be any action to control the speed or there is a problem with the linkage that I'm not seeing.

Anyone have any thoughts?


Last edited by outdoormike; 05-22-12 at 06:56 AM.
 
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05-22-12, 09:03 AM   #6  
outdoormike,


Since you posted such a great pic of that control assembly (the spring looks correct) can you take one of the carb where the throttle link rod is attached to the carb ?

The way I read, You didn't have this high rev issue until working on the carb correct ?

 
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05-22-12, 09:37 AM   #7  
Correct.

I left the mower out in the rain by accident. Never did this since I owned it some 20+ years or so. Would not start and assumed water got in to the carb so I decided to give it a cleaning first and then a rebuild this weekend.

The linkage behind the plate was completely covered with dirt and grease from all those years so in getting it un-gunked I thought I might have messed up something up inside there.

I will try and take the picture you asked for. I assume you mean looking down from above with the air cleaner off?

I can tell you I did not remove that assembly from the carb for the cleaning so it is still as it was before.

 
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05-22-12, 02:48 PM   #8  
I will try and take the picture you asked for. I assume you mean looking down from above with the air cleaner off?
Yes, With the air cleaner assembly off so I can see the throttle shaft and hole the link rod is in.

I can tell you I did not remove that assembly from the carb for the cleaning so it is still as it was before.

You did remove the carb from the engine to clean/rebuild correct ?

 
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05-23-12, 06:00 AM   #9  
Yes, the carb came off.

Did not notice there was a choice for holes. Which one should it be in?

 
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05-23-12, 09:03 AM   #10  
If the link rod has a "U" bend on the end that goes into the carb throttle shaft and not a "Z" bend, Put the link rod in the highest hole. (further-est away from the throttle shaft)

If this is confusing post the engine model and type number so I can see what carb we're dealing with....

 
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05-24-12, 06:42 AM   #11  
Here is the picture you asked for. This is with the lever set to minimum or idle position.

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05-24-12, 09:15 AM   #12  
OK outdoormike,


Since your link rod has the "Z" bend take it out of the top hole and put it in the bottom hole, The spring hooks into the smaller center hole.

BTW, That doesn't appear to be the original carb for that engine but still should function OK.....

 
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05-25-12, 06:04 AM   #13  
Will try it this weekend.

Carb is the original. I'm the only owner of the mower and this is how it came.

BTW: Thanks for all your kind help. Will let you know how it goes.

 
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05-29-12, 08:59 AM   #14  
What a difference a little hole can make!

Moving to the lower hole did the trick. The mower has its power back now.

New issue... Cut the grass on Saturday with no issues. Sunday AM and I had gas all over the mower frame. Turned the engine over and I had gas spraying out the muffler.

I replaced the (worn) float needle when I did the carb overhaul and I made sure the float was level per the instructions from B&S.

I will install a gas shut off valve to stop this while in storage but any suggestions as to what is going on?

 
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05-29-12, 03:02 PM   #15  
Yep, That little movement between holes can make a big difference.

Did you clean the gas tank out and install a new fuel filter ?

I set the float just a little above level just to assure there's no problems, If you replaced the needle it's possible the float has a pin hole in it letting fuel enter.

Quickly remove the bowl and float and hold it between your finger and thumb then shake it bristly, If there's fuel inside you will feel it sloshing around.....

 
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05-30-12, 06:33 AM   #16  
I did install a new metal mesh type filter but did not clean the gas tank. Did not notice the float having any gas but I can take another look.

Perhaps some crud has gotten on the tip of the needle and is preventing it from
closing up.

 
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