Briggs 191707-5661-01 Carb Won't Adjust

[SHOOTERTPP]

Here is my deduction:

The throttle is not fully being closed by the linkage. I assumed that the linkage is supposed to be that way, but after some consideration, I'm not so sure.
It appears the linkage that is on there is holding the throttle plate open anywhere from 1/4 to 1/3 of the way open. Me assuming it was correct, I was trying to adjust the idle air when the butterfly was calling for more fuel. Ain't never gonna adjust properly.

The arm on the throttle mechanism cannot travel any further forward to close the butterfly more.

Since I am not the owner, I have no idea what someone else may or may not have done. Looking at the end of the wire that connects the rod to the arm on the throttle shaft,
it appears to me to have been cut with a pair of pliers or dikes, as it is a bit pointed. I would assume the factory ground the ends flat before bending the wire.

On a whim, I removed the carb and removed the throttle linkage, but left the choke linkage in place. I manually closed the butterfly/shaft until it stopped completely and tried to start it. It would not start.
I then held the butterfly open just a very little bit and it started right away and idled nicely at about the right speed. I adjusted the idle air until I found the "sweet spot". I then open the butter fly wide open and adjusted the high air until it quit putting out any black smoke.

I then returned it to idle and back to wide open slowly a couple of times and it accelerated nicely. I then snapped it wide open from an idle and to my amazement, it jump right up to full speed without any hesitation or stumble.

I then removed the carb and hooked up the throttle linkage and reinstalled. Back came the problems of it not wanting to idle or accelerate and putting out black smoke when given any throttle.


Any suggestions???? Could it be a governor issue?

 

[Mikel1]

What are your settings on the main & idle from bottomed out position now? I don't see anything out of the norm with your pics. I have 2 flatheads with the same setup that are out 1/4 on throttle plate, both run great.

 

[Gearhead0101]

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.

I've never heard of one that didnt, but on some of them there's just a notch in the float that holds the needle instead of a separate retainer. It might not be (and probably isnt, it barely makes sense as I'm typing it) but if you had a serious enough vacuum leak, it could theoretically interfere with carb adjustment, but a leak that severe would give more symptoms than just that.

 

[SHOOTERTPP]

What are your settings on the main & idle from bottomed out position now? I don't see anything out of the norm with your pics. I have 2 flatheads with the same setup that are out 1/4 on throttle plate, both run great.

Started out at 1 1/2 on each one. I can get it to idle good but the RPM's are high. If I run the throttle to high and try and adjust the high side it races out of control. And when you move the lever back to idle, the RPM's don't drop.

Without the throttle rod in place, I can adjust each one and it runs and and adjust just fine.

I'm doing a barbecue cook off right now, but will try and get a video of it on Sunday.

 

[Mikel1]

So with all linkages hooked back up, you can't go from full throttle back to idle. Is the throttle plate staying open when this happens and not closing? If that's the case then you have a governor issue. You can take off governor spring and manually open/close throttle to confirm.

 

[SHOOTERTPP]

Mike, I don't know. I hadn't noticed. What is puzzling me, is why with the linkage removed, it will perform like it should idles corrctly and will rev up and come back to an idle with no problem, but as soon as you hook the linkage back up, it runs rough at idle and wont rev up very quickly and when it does, it runs way to rich, all without any adjustments to the carb.

What you saying makes sense, the governor is what to do one thing while the carb wants to do something else.

I'll have to read up on the operation on the govenor on this thing.

I'll try that in a few minutes. I good some much need sleep after the BBQ marathon Friday night and Saturday and now have a much clearer.

 

[SHOOTERTPP]

I tried again today with all the info but to no avail. I finally built a longer linkage to allow the throttle butterfly to close more and all is well. I can now use the idle adjustment screw ( not the idle air adjustment) to raise or lower the idle. It now idles and revs up and returns to idle on command.

Now for the next problem, non engine related. When I engage the pto switch the engine dies. I tried finding the wiring schematic but no luck so far.
I did disconnect the pto clutch at the connector down by the deck and the engine still dies when the PTO switch is engaged.

Anyone have a clue?

 

[Mikel1]

Incorrect linkage or tampered with?

 

[SHOOTERTPP]

It looked factory, but the again it didn't.

Like it shows in the picture the butterfly would not close very much. I think someone may have cut and rebent the factory linkage to give it more fuel to keep it running when the carb became dirty.


I figured out the problem I asked about in my last post. Some one had disconnected the seat safety switch and had grounded the white wire that comes out of the wire loom that goes to the safety switch to the frame.

Removed the wire from the frame and it will now run, engage the PTO and the blades turn. All is well.

The bad thing is John Deere no longer sells the seat safety switch for that model. I have the guys at the deere dealership trying to find a replacement.

 

[Mikel1]

People do some odd stuff sometimes. Well then it sounds like your almost done. Your rancher friend should be pleased with your efforts.:thumbsup: