Help with 9N governor troubleshooting

I was out running my 9N today snowblowing 18" of wet snow. As I was coming up my driveway it started running rough, the rpms kept dropping then coming back. When I got to the top of the driveway the rpms went to maximum and stayed there. The throttle lever had no effect on rpms, the engine stayed at max rpm. The governor has been acting intermittently sluggish lately as well but the tractor has been usable up until this point.

I checked the governor spring, it was loose so I took it off and adjusted it until it was snug but with no preload per the FO-4 manual. I started it back up and the rpms were screaming so I decided to put the tractor back in its parking spot. When I engaged the pto to lift the snowblower the rpms dropped but the governor kept hunting and the rpms were all over the place. The throttle lever still had no effect on rpms.

What else can I do to troubleshoot this? I'm not very familiar with governors, is it time for a rebuild?

Thanks
 
Standard test for gov function is to hold the rod from the gov to the carb and try to rev up the engine. The gov should fight you and pull
back. Governors are not hard to overhaul. When you remove it make sure you mark which bolt goes on the the top and which one goes on the
bottom. Obvious signs of wear are flat spots on the balls.
 
How the governor is supposed to work - The carb arm spring rotates the carburetor butterfly to the wide-open position, and the governor tries to close the carburetor butterfly thereby limiting engine RPM.

If the linkage is connected correctly and the governor is not limiting engine speed you have an internal problem with the governor. It's time to open it up for a closer look.
 
Thanks guys, the governor is definitely not fighting back if I hold the rod to the carb. I'll pull it off tomorrow, open it up and see how it looks inside.
 
(quoted from post at 06:03:50 03/09/18) Thanks guys, the governor is definitely not fighting back if I hold the rod to the carb. I'll pull it off tomorrow, open it up and see how it looks inside.

Well, I was wrong about this. I double checked it and the governor does fight back if I hold the rod.

I think the issue is with the carburetor. I disconnected the linkage from the governor to carb and tried to rev it manually with my hand. Moving the throttle shaft from wide open to closed has no effect on engine rpms. When I start it most of the time the rpms are at full throttle but sometimes the rpms will drop slightly and the engine will misfire.

Do you think the float might be stuck? I pulled the fuel elbow to check the strainer that goes in the carb, it was nice and clean. The sediment bowl assembly was replaced a few weeks ago as well so I'm pretty sure fuel flow isn't an issue.

One other thing that I noticed is it appears that the throttle shaft isn't installed correctly. The idle speed screw does not come into contact with anything so that you could adjust idle speed. I haven't owned this tractor for that long so who knows what the PO did with the carb. It has been running fine up until this point so I don't think that caused the problem but here's a couple pictures so hopefully somebody can tell me if it's installed wrong:


mvphoto12519.jpg

12518.jpg

mvphoto12520.jpg
 
(reply to post at 13:58:09 03/10/18)

I'm pretty sure fuel flow isn't an issue.

don't guess, perform this test. will your fuel system, with gas valve turned on at sediment bowl and plug removed from bottom of the carb, move enough fuel to fill a pint jar in two minutes? if not, then it's likely to be a problem.
 
(quoted from post at 12:40:14 03/10/18)
(reply to post at 13:58:09 03/10/18)

I'm pretty sure fuel flow isn't an issue.

don't guess, perform this test. will your fuel system, with gas valve turned on at sediment bowl and plug removed from bottom of the carb, move enough fuel to fill a pint jar in two minutes? if not, then it's likely to be a problem.

I took your advice, it would only feed about 1/2 pint in 2 minutes from the bowl drain. After that I disconnected the fuel line at the carb to see how fast it would feed from there to eliminate the sediment bowl and fuel line. It fed over a pint in 2 minutes from the fuel line.

I decided to pull the carb off and found the problem. One of the throttle plate screws was missing which caused the plate to hang up at full throttle which explains why there was no throttle response. The missing screw was nowhere to be found so I decided to get a rebuild kit from TSC. I disassembled the carb and I'm soaking it overnight in mineral spirits, I'll put the kit in tomorrow. The screw was nowhere to be found inside the carburetor. I'm wondering if some idiot lost the screw when putting it back together and just put the plate on with one screw.
mvphoto12536.jpg
 
I'm wondering if some idiot lost the screw when putting it back together and just put the plate on with one screw.

You'll never know - It is rare to find someone who actually takes pride in their work.

Be sure to stake the new screws to prevent them from backing off.

Glad you found the problem!!
 

More likely they didn't use threadlock on the little screws and it vibrated out. If so, wonder where that sucker is? Thanks for taking the time to post pics. It is so much easier to get help that way. I need to get better at doing that.
 
(quoted from post at 15:40:33 03/11/18)
More likely they didn't use threadlock on the little screws and it vibrated out. If so, wonder where that sucker is? Thanks for taking the time to post pics. It is so much easier to get help that way. I need to get better at doing that.

I was wondering that myself. I searched high and low when I had that carb apart yesterday. That screw is still among the missing.

I finished the rebuild kit and installed the carb today. It's running good although it seems to idle higher than it did before. I wasn't able to adjust the idle any lower. If I disconnect the linkage to the governor I can manually move the throttle to a lower rpm, almost as if the linkage isn't long enough.

Another issue it's had since I bought it is the hand throttle lever won't go down to its lowest setting on the qudrant. The FO-4 manual on page 42 says to hold throttle linkage at point A and bend linkage to adjust but it doesn't go into much detail. What exactly am I supposed to bend? The linkage between point A and the governor is too short to adjust and make the hand lever go to its lowest point on the quadrant.
 
(quoted from post at 17:56:39 03/11/18)
(quoted from post at 15:40:33 03/11/18)
More likely they didn't use threadlock on the little screws and it vibrated out. If so, wonder where that sucker is? Thanks for taking the time to post pics. It is so much easier to get help that way. I need to get better at doing that.

I was wondering that myself. I searched high and low when I had that carb apart yesterday. That screw is still among the missing.

I finished the rebuild kit and installed the carb today. It's running good although it seems to idle higher than it did before. I wasn't able to adjust the idle any lower. If I disconnect the linkage to the governor I can manually move the throttle to a lower rpm, almost as if the linkage isn't long enough.

Another issue it's had since I bought it is the hand throttle lever won't go down to its lowest setting on the qudrant. The FO-4 manual on page 42 says to hold throttle linkage at point A and bend linkage to adjust but it doesn't go into much detail. What exactly am I supposed to bend? The linkage between point A and the governor is too short to adjust and make the hand lever go to its lowest point on the quadrant.

I had a similar problem, however the other way. For slow idle I was going way above the bump stop on the quadrant. What I found was that little "ball arm" on that long linkage that runs from the front of the tractor to under the battery tray was bent. I had to take it off and put a torch to it. Gotta go slow if you have to do the same. Also that front linkage bracket is held down by head bolts and one of them penetrates the water cavity, so if you loosen it tighten it back down while you work on the linkage or you will have a mess.
 
(quoted from post at 18:09:08 03/11/18)
(quoted from post at 17:56:39 03/11/18)
(quoted from post at 15:40:33 03/11/18)
More likely they didn't use threadlock on the little screws and it vibrated out. If so, wonder where that sucker is? Thanks for taking the time to post pics. It is so much easier to get help that way. I need to get better at doing that.

I was wondering that myself. I searched high and low when I had that carb apart yesterday. That screw is still among the missing.

I finished the rebuild kit and installed the carb today. It's running good although it seems to idle higher than it did before. I wasn't able to adjust the idle any lower. If I disconnect the linkage to the governor I can manually move the throttle to a lower rpm, almost as if the linkage isn't long enough.

Another issue it's had since I bought it is the hand throttle lever won't go down to its lowest setting on the qudrant. The FO-4 manual on page 42 says to hold throttle linkage at point A and bend linkage to adjust but it doesn't go into much detail. What exactly am I supposed to bend? The linkage between point A and the governor is too short to adjust and make the hand lever go to its lowest point on the quadrant.

I had a similar problem, however the other way. For slow idle I was going way above the bump stop on the quadrant. What I found was that little "ball arm" on that long linkage that runs from the front of the tractor to under the battery tray was bent. I had to take it off and put a torch to it. Gotta go slow if you have to do the same. Also that front linkage bracket is held down by head bolts and one of them penetrates the water cavity, so if you loosen it tighten it back down while you work on the linkage or you will have a mess.

That's what I was afraid of, it doesn't seem like an easy job to bend that arm enough to adjust it correctly.
 

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