Briggs 191707-5661-01 Carb Won't Adjust

[SHOOTERTPP]

Hey folks.

I'm working on an 81 or 82 model, John Deere 108 Lawn Tractor for a rancher friend of mine out in west Texas.

It has an 8hp Briggs 191707-5661-01 engine. It has the 1 piece FLOJET carburetor on it.

Originally all I was going to do was replace the starter. Someone had put an iron pinion gear of the aluminum ring gear so I ended up replacing the ring gear as well. While I was in there I decided to check the gap on the points and when I took the cover off, I found it was full of oil so it replaced the point system with the new magnetron coil eliminating the points and condenser.

Before I started this the engine would ilde, but when given fuel it would run rich and put out some black smoke.
After replace all the other parts and starting it. The same thing happened. I purchased a rebuild kit for the carb, clean it and replaced all the parts.

It still won't adjust. I started as per the instructions 1 1/2 turns on both the main and idle screws.

No matter how I try to adjust it, it won't work right. If I screw the main jet in, the idle comes up and it quits putting to back smoke, but it runs at what seems like full throttle.

Any ideas on what I could be doing wrong?

 

[Mikel1]

Sounds like there's still a blockage in the carb if it's still running at full throttle with main all the way in. I'm guessing air filter is clean?
Here's a link for you- http://outdoorpowerinfo.com/repairs/briggs_large_one-piece_flo-jet_carb.asp

 

[SHOOTERTPP]

Air cleaner is not on due to the idle air adjustment screw being under the air cleaner. It will run just about the same way with both adjustments all the way in as it does when they are at the starting point of 1 1/2 turns. As I screw the main needle in, the engine picks up speed to the point where I think is running close to max rpm.

I used two can of cleaner to clean every passage in the card that I could find/see. It's easy or remove and I can clean it again after I remove the new jets.

 

[SHOOTERTPP]

Mike, I appreciate the link to the procedures. I'll remove the carb again tomorrow, get some more cleaner and give it another try using the pictures in the link.

Thank you!

According to the rancher the mower hasn't been used all that much. Most of its life it has been sitting under a covered carport.

For all I know a mouse has died in the body of the carb and is restricting air flow. I did not remove the welch plug but will tomorrow.

 

[Mikel1]

Your welcome, I hope that helps you out. I'd hope you would've noticed a mouse in there:laughing:.
I did have to clean an atv carb 5 times before it ran right. The person I bought it from had changed out a rusting tank to a plastic tank but didn't change out the fuel shutoff(petcock). So the rust was in there clogging back up the carb.

 

[SHOOTERTPP]

I just finished an ATV carb on a 1988 Honda 300 TRX for my brother. It had set for a bout 5 years after he had the engine rebuilt. It was a breeze compared to this one.

The one thing I'm not sure of is if anyone has been into the carburetor before. I am thinking some one has.

One of the ears that holds the float in place is broken and I didn't find the missing piece in the fuel bowl when I disassembled it. The other ear is holding the pin in place.

One thing I may have missed, is there supposed to be a retainer to hold the needle valve to the float? When I disassembled it, there wasn't one on there, but the link shows one in picture 12. The instructions also mention the need for one if there was one there when it was disassemble, but say to leave it out if there wasn't so I didn't put it in.

I was thinking it was odd it didn't call for one but thought it may just fall down by gravity, but am now thinking I was wrong. I'm not saying that's what could be causing the idle problem, but not being a carb guy, I don't know.

 

[SHOOTERTPP]

I must have the small body as my carb, while very similar, is a bit different than the one in the link.

I have taken some pictures and will post later.

 

[Mikel1]

That atv carb was on an 87 Honda Fourtrax 250.
With the float ear broke, is the float operating normal?
Here is a link for 191707-5661-99 carb diagram, you may be able to google to find the 01.
Diagrams

 

[SHOOTERTPP]

The ear is broken on the Briggs. Yes the float works even with it being broken. The pin is tight enough on the other side the pin only drops about 1/32 to 1/64 on an inch on the broken side.

I'm leaning now, it being not the carburetor that's causing the problem.

I took the carb off and then put it back on with the choke wire attached but with the throttle linkage removed.

I closed the throttle by using the ear on the back side of the carb. It didn't start. Next I cracked the throttle open about where in normally starts at. It started right away, but at a higher than normal idle.

I then very slowly moved the throttle in the direction it should go to idle down and the idle slowed to what I consider a normal idle speed. I then adjusted the low side to where it ran very smoothly.

I then revved it up to what I think is max rpm and adjusted the high side to where it sounded good and wasn't puttin out any black smoke. I then returned the lever back to idle and it slowed right down to a nice idle. I them snapped the throttle open and it accelerated right away without any hesitation or smoking. Just like it should.
Return it to idle and moved it to high several times and it was perfect.

Took the carb off and replaced the linkage for the throttle and the problems returned. Go figure.....
Possible governor problem?

 

[Mikel1]

Oh I see so it's not the actual float. Have you tried moving the governor spring, usually a few holes to try. Another link for you- Adjusting the Governor | Mower Maintenance | Briggs & Stratton FAQ