I did the static adjustment multiple times prior to filming. I found the problem, which was a failed governor gear mechanism - kzfaq.info/get/bejne/eZeWmNpymJu5aZ8.html

Dude, I had no clue how to fix this issue. Came to this comment and it helped me get my ex mark zt mower back idling properly and understand these inteks better. Ty

Did you figure out the problem I’ve this exact same problem

​@@dylankelly7903 Yes... I pulled the engine again, cracked it apart... again, and found the new governor I installed was blown apart... evidently I installed it wrong because after I installed the new one, it still ran full blast so it had to come apart on the "first" start up... anyway, I pulled it apart again, installed a new governor correctly, set it and of course made sure I had the springs right and she ran great after that. Those governors are kinda tricky to install trying to get those arms just right and get that cup set in the middle just perfect... then it should just snap right down... no beating or tapping with anything... that cup should just push down with a little thumb force and snap in place. That Teryl Dactyl dude has a vid showing how to do it but he makes it look easy... I found it to be kinda tricky altho this was my first experience(s) tearing one of these engines apart... but I damn sure have some experience now... took me about 4 engine removal, tear downs, and reinstalls to figure it out.

@@theoldstyle7453 sorry to hear that it took you a few attempts but glad you finally got it sorted. I went through having to triple-check things as I was reassembling mine and had a similar experience seating the gear. This was the first time I opened up a small engine. I managed to get it done in one go but it took me longer than it would someone who has significant experience.

did you find a solution, replaced my govenor just the same??

@@1mikechung replaced the internal gear in the crankcase? Was it failed and in pieces like in the follow-up video? I exhausted all possibilities until I found there was nothing else it could be and the smoking gun that the governor gear is totally dead is that when you start the engine, the arm for the governor just "flops around". That was what convinced me to crack open the engine to find my failure. In this thread, you see two folks had the experience of installing a new one, one found they did it incorrectly and had the same outcome as when they started. If you aren't trained and DIY-ing this...it isn't hard but you can make mistakes.

That device is supposed to act as thermostat and change the throttle based upon temperature, if I recall correctly. As you say, parts diagrams vary. Some versions of the throttle controls have it, some don’t. Maybe in a pinch, your wire copies will work, I inadvertently bent mine and bent them close to original and it seemed to be okay but elected to buy new ones and replaced them.

It was clearly marked on the parts diagram when I ordered a replacement. Get/confirm model number of engine and search for the parts diagram and you should be able to find it on the diagram...

We just had the same issue! Took us about 4 days to finally figure it out 😥

@@toughtimes6596where’s the picture? Need help bad!

1) Do you have a tachometer to quantify how high it revs and to make the adjustments? 2) Do you have the factory repair manual for your specific model number? 3) Did you contact B&S/confirm what the correct max RPM for yours is at full-throttle to adjust the governor to? 4) Did you adjust the linkage right? 5) You can always take it to a professional to diagnose/repair (will likely be cheaper than. anew engine) but they are going to hate you when you tell them what you did and you should tell them what you did to this point so they don't chase their tail trying to figure it out.

@@AshrafFarrag Hi, I will ask my local Dealer and I will explain the fault and seek advise. I can always take the engine to them which will save a lot of costs when I can do the costly bit, which is time. I do have 30 years experiance fixing Car engines, the governor is new to me. I use to remove govenors in my Honday GX160 Engines when use to Race the in GO Karts with 2 engines on. We relied on the valve springsbounce a high revs to control RPM, never blew an engine up in 6 years of racing. Thanks

The model number of this particular engine is 44S777-0016-G1. I used the Briggs and Stratton service manual #273521. The black and white diagrams might be helpful in addition to the video.

Get the parts diagram for your specific engine model number and the service manual. You will see the part number for seals in the parts diagram for the governor shaft and the service manual will tell you what must be replaced to get to the shaft to replace those seals and the other components to remove to get to it (as well as any seals or parts for those that must be replaced). Remove engine from chassis, pull oil pan, remove governor shaft, replace seals, reassemble, replace whatever you want for preventative maintenance while you have it apart along with any sealant compulsory replacements for the subassemblies you had to remove to replace the shaft seal. Might be more work than you want to do for an oil seal if it is not heavily leaking or just seeping where you can regularly check the oil level. What I wouldn’t try, is to seal with a tube of random stuff externally and risk the governor shaft not operating properly.

Fuel in crank case

It has seal on the shaft

Without the engine operating, the linkage can move and the plastic on the linkage can touch the thermostat device anywhere from the upper to lower positions. As I understand, the thermostat rotates depending on the temperature range it is designed for and in doing so, adjusts the choke operation.

Problem found: kzfaq.info/get/bejne/eZeWmNpymJu5aZ8.html

Disassembled immediately, confirmed dead governor, thoroughly cleaned/removed debris, inspected everything, found no other damage, installed new governor gear, and it's running just fine 25+ hours later.

@@AshrafFarrag Yes, I've since watched several videos where this doesn't end catastrophically. Apparently, I'm just very unlucky.

@@cornpop7805 I "survived" because of this chain of events: it was running fine and I stopped it to park. I restarted it and upon restart, I heard the engine go "fast" and I immediately shut it down. A couple of re-starts to try and troubleshoot the governor linkage with me shutting it down immediately (like a few seconds) of it running ungoverned. How long did your run ungoverned?

@@AshrafFarrag Hi, Had a bad misfire, replaced carburettor. Engine now revs very high. Took engine out replaced with a new governor, did not look damaged at all. Adjusted governor to carb as per instructions. Still revs high. Noticed the Governor arm does not seem to move througout the rev range. Any ideas? Thanks

Did that and checked many other things. It still wanted to run away. I was grasping at straws that there was some external play or something else that was causing it and posted this video to see if any eagle eyes would see something abnormal before having to pull the engine off the chassis and take it apart...which I did and found the governor in pieces in the crankcase… So, yeah, I would try to readjust it and everything else you can do externally but if it was governing correctly 10 minutes beforehand when shut down and you restart the engine to move it and it runs away, this shows it is possible the mechanism can fly apart upon restarting the engine. 🤷‍♂️

Check all the linkages and governor adjustment. RPMs up and down (surging) can be a carb issue. Look for a video on surging to see if that’s it. Governor that’s totally gone will try to run to 4000 RPMS and won’t slow down and will be terminal. Surging tends to be carb issues.

@@AshrafFarrag did you find a solution. I replaced governor and carb.

@@1mikechung follow-up video is in description of the failure. Replaced the governor mechanism in the crankcase and it runs great. The governor linkage won't resist or move on its own to pull on the throttle linkage with the engine running if the internal mechanism is failed.

That was one of the first things I checked. Unfortunately, you can not adjust what is no longer there: kzfaq.info/get/bejne/eZeWmNpymJu5aZ8.html

Read description. Video shared with small engine repair forum to verify if play in the linkage was normal. All external governer linkages are correct. The governer is destroyed inside crankcase as shown in the follow-up video.

It is both a rev-limiter and a constant engine speed/load regulator. This application needs it for engine speed regulation. Without it, you would have to constantly open and close the throttle to ensure it doesn't potentially overrev while dealing with the changing load on the engine from cutting patches of grass of different densities while the hydrostatic drive is also subjecting the engine to various loading for propulsion. On a zero-turn like this, you need both hands to control the direction and would then have a third control to be able to constantly operate the throttle while controlling movement...that is way much to deal with...set engine speed and go about your business...