I have a 1995 Craftsman mower, 917.380450. The Tecumseh engine has stamped on it 143.434082. The governor no longer functions. The governor rod "freewheels, i.e., I start the engine, with throttle disconnected, open the throttle 3/4, and there is no resistance on the governor arm. None. I can turn the arm/rod assembly almost 360 degrees with no response. Nothing is connected internally, that I can tell. The engine, when started and nothing connected, runs at idle, not wide open. I can open the throttle butterfly, secure it, and the mower runs fine at a moderate speed, except that it backfires. ( I can find no lean mix adjusters on the carb but that's another story.) The question is: Can I run the engine safely at moderate throttle? (Un-governed completely. ) I saw a post somewhere on how to replace the governor shaft, gear assembly, spool, lever, etc. I can certainly do that, but I'd rather not since I use this mower infrequently. I confess it has some sentimental value as it was the first mower I ever bought after getting married, buying a house, having twins, etc. etc. What do y'all think? Will the engine blow up if I run it ungoverned at moderate throttle?
The engine runs at 3500 rpm when governed
Most will happily do 4000 RPM
When you get above those speeds it is Wham Bam thank you mam.
Some will toss a rod at 4100 others will be fine up to 5000
So it is a question of how good you think your ear is.
On go karts we bypassed the governor and set the foot gas pedal cable where it could not get in the rpm level to self destruct. I think you could unhook your throttle cable from the governor arm move it to the carb and lock the sheave of the cable at a safe place with the dash control full on so you can never accidently reach rpm's that will break the connecting rod .
Absolutely correct, something is not right here! The governor absolutely has failed. I have removed the governor arm completely. No spring, no nothing. I have disconnected the throttle mechanism completely. The carb is just sitting there, not connected to anything. Normally the engine would, as you say, scream wide open until it self destructed. Instead, when I start it up, it runs along fine at idle.
I can manually open the butterfly a bit and the engine responds fine, and STILL runs fine. So, I'm concluding that internally, the governor gear assembly has cracked or something of that nature. Rather than open up the engine, etc, I'm just going to run the mower at 2/3 throttle, max. That's what I always did, anyway. I just didn't know how to just exactly what 2/3 throttle even was. Now I know just to trust my ear. I know from years of listening to the mower what it should sound like!
True, true. And I thought about it. The parts are available and cheap. But I had to ask myself, if I always ran the mower at the same speed, and if I never cut tall thick grass, what good is the governor really doing me anyway?
What you will find is the mower will forever be bogging down as the throttle can not open up to maintain engine speeds.
Cut quality is very dependent upon engine speeds as that determines blade speeds
Then there is the problem of loose bits of metal bouncing around in the sump which will eventually end up getting between the gears on the cam shaft,
What you will find is the mower will forever be bogging down as the throttle can not open up to maintain engine speeds.
Cut quality is very dependent upon engine speeds as that determines blade speeds
Then there is the problem of loose bits of metal bouncing around in the sump which will eventually end up getting between the gears on the cam shaft,
This is very helpful, thanks. I hadn't thought of the metal bits. There's the possibility of the governor rod getting demolished if it's no longer riding on top of the governor spool. And of course the flyweights , metal gears etc. A question though about governors in general: Suppose I had a tach and set the RPM's manually to the max safe limit for this engine. And then I always mowed at that max speed. Wouldn't the question become moot of the governor needing to open up the throttle to avoid bogging? The engine would already be running at the max safe speed, correct?
You can't mow at that setting! The throttle does *NOT* set speed, but rather fuel/power delivered - shaft speed is then directly related to load on the engine. So, what that means is that to avoid overspeeding, you can only set the throttle limit with no load (which is a very, very, low power setting). Hit the grass and speed will either sag massively, or it may stall outright. You would be amazed at the difference in throttle butterfly position between idle and full load with the exact same shaft speed.
True, true. And I thought about it. The parts are available and cheap. But I had to ask myself, if I always ran the mower at the same speed, and if I never cut tall thick grass, what good is the governor really doing me anyway?
I had a Snowbird many moons ago that had the same problem. I did what u are considering - connected the cable straight to the throttle . I just needed to manually give it a little more gas when throwing snow.
For your situation, i think if anything broke off it would be sitting at the bottom of the sump. It is not like you cut grass going 20mph off roading for it to bounce around and break something. Then again, this is a hacker point of view vs repair it properly for a customer.
