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-   -   Governor Removal Safety Reality Check (http://www.diygokarts.com/vb/showthread.php?t=16518)

Doc Sprocket 05-12-2012 07:30 PM

Governor Removal Safety Reality Check
 
It is absolutely amazing how often we run into this here- and how often we find ourselves banging away on the keyboard, typing out the same old answers. So, I felt it was a good idea to write up a little blurb on the topic- If requested, I'll sticky it- to hopefully save us all some future work. Let's start by outlining the governor's job description. Everyone knows that the governor tries to limit engine speed to (usually) 3600 RPM. But wait- there's more. The reality of it is this- the governor's job is to try to MAINTAIN 3600, not just limit it. The governor reacts to changing loads on the engine- decreasing throttle if it starts to run too fast, and INCREASING throttle if it starts to bog. This is why it is called a "governor", and not simply a "rev limiter".

Now- On to the question: "If I take out my governor, is the flywheel gonna go off like an atom bomb, blowing semi-molten schmutz everywhere, and killing every living thing in a 15-block radius?"

The short answer is no. The long answer: There are many factors involved here, and each must be carefully considered.

1) I always advise people that IF they are going to run well above governed RPM, to do it by fully removing the governor's internal mechanisms, and NOT simply bypassing it externally. Many governors are designed in such a way that if over-revved, can suffer component interference inside the crankcase, and/or have internal parts forced right off the shaft and bounce around loose inside the crankcase. Either case can cause severe engine damage. NOT an "explosion", just largely F'd up internals.

2) IF you are going to run ungoverned with an otherwise stock engine, keep the factory spec valvesprings in place. At a high enough RPM, weaker springs will cause a condition known as "valve float" or "valve flutter". This occurs when the valves cannot slam closed fast enough before the next cycle. This cause compression losses, and as a result, prevents the engine from spinning faster than that point. Valve flutter tends to occur in our engines around 5000-5500RPM. Your results will vary, based on your individual engine, spring condition, etc. Valve flutter occurs at a lower RPM than it would normally take to cause a flywheel mishap.

3) IF you want to get into RPM ranges HIGHER than this (say 5500+), now is the time to go shopping for high-performance internals. A billet aluminum flywheel, connecting rod, and stiffer valve springs are what's called for. Stiffer springs allow the valves to react faster, so at higher RPM, the valves won't float- NOW things really do have the potential to get a little crazy, so it's time to reach into your pockets for better quality parts.

4) Your connecting rod is MUCH more likely to fail than your flywheel. I have witnessed MANY more conrod failures than flywheel failures. In fact, I have never seen a flywheel failure. Most here haven't.

5) Contrary to popular belief, a flywheel is NOT going to vapourize at 3601 RPM. This is NOT why your engine is governed to 3600 RPM. Your engine is governed to 3600 RPM because it is an industry-standard operating speed for all the implements these engines are designed to power. Let's NOT lose sight of the fact that these are industrial stationary engines- made and marketed with the primary purpose of powering equipment. Generators, pumps, power washers, welders, cement mixers, tillers, trenchers, tampers- you name it- and the implement are designed to run at 3600 RPM- So the engines are factory set to 3600 RPM. It's that simple. When a flywheel is manufactured, it is designed to run well above normal operating speed. It's called a safety margin.

6) NOTHING is 100% guaranteed. You can do everything completely properly, and have a flywheel fail at a "normal speed". OR, you can do everything wrong, and run the he// out of the engine at 7500 RPM on a stock 'wheel for a lifetime and never have a problem. Sometimes, there's just no accounting for "Spit Happens". Write that down.

7) IF you are running an otherwise stock, ungoverned engine, is it adviseable to avoid excessively free-revving the engine. Use proper gear ratios to keep a bit of a load on the engine at full speed, wide open throttle. Don't try to rev the wee out of the engine with the clutch, chain, or belt off. A load on the engine helps keep harmful vibrations (harmonics) in check. If you have an insanely long, steep downhill stretch in your riding route, back off the throttle going down it. If you hear the valves floating or the engine starting to over-rev, apply some brake force. Coasting too fast can force the engine to spin even faster than valve flutter can prevent.

8) Inspect your flywheel before removing your governor. A previously damaged flywheel can break apart at a completely unpredictable speed. Damage may not be visible (spit happens) but if it IS visible, replace it.

9) If you have to remove your flywheel for repair/maintenance, remove it properly. Do NOT beat the he// out of it with a BFH or pry on it. Invest in a flywheel puller. Failing that, try the following: Loosen the retaining nut until the nut is flush with the end of the shaft. Now, hit the nut squarely and sharply a couple times with a hammer. Most times, this will do it. You can also aid in loosening the flywheel with mutiple taps around the circumference with a soft-faced mallet or deadblow hammer. Do NOT beat on it with a steel hammer.

10) If you need to hold the engine from turning while you are tightening/loosening a crank bolt or clutch, do NOT wedge a screwdriver or bar in between the flywheel fins. Although this is not likely to crack the 'wheel, a fin could break off. This will throw the 'wheel's dynamic balance off. An out-of-balance 'wheel is just asking for trouble. Same goes for sawing off alternate cooling fins (an old performance trick). If your fins are cast into the 'wheel, don't do it. If you have a Honda, clone or other engine with plastic fins, go for it.

11) Handle with care. Once you have the 'wheel off, don't drop it...

So- Armed with the above information, go ahead and make an informed decision. This guide arms you with what you need to know, to decide whether removing your governor is a feasible idea, and how to handle things if you do. And remember (for all the "Armageddon-is-coming-prepare-to-meet-thy-maker-in-a-sintered-metal-flywheel-induced-world-war-3-esque-everybody's-gonna-die-including-the-cockroaches-in-the-cupboard"-nervous-nellies out there... Spit happens. On the one hand, your stock flywheel will very likely be fine. On the other hand, even a performance parts could fail. Spit happens.

One last point here- For those that may not yet be ready to dive into their engine and come out with a handful of governor parts- Some engines (most notably Hondas and clones) have a VERY user-friendly means of governor adjustment. This adjustment is designed to fine-tune the governed speed to spec, but makes it super easy to gain a few hundred RPM- usually you can bring your GOVERNED MAX to 4000-4200 RPM with the turn of a screw. Your governor will still do it's job, but you'll run a little faster. Locate the manual throttle control on your engine- the little lever you would slide to increase or decrease RPM if you didn't have a remote throtte (gas pedal). Behind that lever is a screw with a spring wrapped around it- Notice how the throttle rests against the tip of that screw when you move the lever to the "fastest" position? Great. Remove that screw. Presto- instant maximum RPM increase- no fuss, no muss.

It is also worth noting that these engines were designed to run at 3600 RPM, day in and day out. If you do run faster, the engine will wear faster. Fact of life. Treat it well, maintain it well, and you'll never notice the potentially shorter lifespan.

speed1 05-12-2012 08:25 PM

Awesome post. very informative , you know your stuff...Bob

rcarteraz07 05-12-2012 10:00 PM

Most informative and hilarious post today!! Thank you! Lol

r_chez_08 05-13-2012 01:49 AM

Sticky?
Lol, I love the difference in attitude between here and OMB. Their policy is if the governor is removed, a billet rod and flywheel must be installed.

fowler 05-13-2012 02:49 AM

good read will be usful for beginners
u covered a few differant useful points

it is a good attitude of "it" happens
u will be fine but dont forget parts will sometimes break regaudless what they are made of

sideways 05-13-2012 03:33 AM

Quote:

Originally Posted by r_chez_08 (Post 206661)
Sticky?
Lol, I love the difference in attitude between here and OMB. Their policy is if the governor is removed, a billet rod and flywheel must be installed.

One day.... I'm gonna sign up there with a 10000+ RPM Victa on stock internals and flywheel and watch heads explode.

r_chez_08 05-13-2012 05:06 AM

Lol, they would probably ban you in 5 seconds. It would be better if it was a clone.
Be like- Heres my new clone I built. It runs on race methanol, has a tuned tilly carb, 15:1 static compression with a milled, ported, polished and big valve head. Oh and it has #45lb valve springs and an iksy grind cam. it turns over 10k and produces 20+hp. Oh and a 'special' rod and flywheel :roflol:

Jcotz 05-13-2012 06:38 AM

Very informative and definitely sticky worthy. I know a lot of people (including myself) are getting tired of explaining the pros and cons of governor removal.

Doc Sprocket 05-13-2012 09:05 AM

1 Attachment(s)
Okay- I'll sticky it- thanks. I don't like to do that without folks' input first- looks too much like shameless self-promotion...

Speaking of shredded rods, I just pulled this engine out of a friend's junk pile.

klicky96 05-13-2012 09:03 PM

Quote:

Originally Posted by toystory_4wd (Post 206712)
Okay- I'll sticky it- thanks. I don't like to do that without folks' input first- looks too much like shameless self-promotion...

Speaking of shredded rods, I just pulled this engine out of a friend's junk pile.

I wanna meet the person who did that. I have ran every small engine I've had on my karts without a governor and the only thing i've had to do was replace a had gasket, thats it. But then I see people put con-rods through the block and I think, "how the **** could I be so **** lucky?" ha, I've had 3 Tecumsehs, 4 Briggs, and 1 Honda Clone. I've never blew the rings out of it, i've never thrown the timig out, i've never sheared a fly-wheel key, nothin. ha

jman231994 05-14-2012 02:20 AM

Quote:

Originally Posted by sideways (Post 206675)
One day.... I'm gonna sign up there with a 10000+ RPM Victa on stock internals and flywheel and watch heads explode.

You'd better let us see the beast before them hahaha

jamyers 05-14-2012 10:15 AM

Quote:

Originally Posted by toystory_4wd (Post 206624)
...Now- On to the question: "If I take out my governor, is the flywheel gonna go off like an atom bomb, blowing semi-molten schmutz everywhere, and killing every living thing in a 15-block radius?"

Actually, I say that the answer to that person asking that question is "Yes - YOU should keep your governor!".

Because if they (1) won't take the time to read the Stickies, then (2) they aren't going to take the time to do decent work on the rest of their kart/engine, then (3) they're going to kludge it up and blow it up in the end anyway.

My answers often depends on the asker, not the question. It kills me when somebody WILL take the time to Register and Ask a FAQ, but they won't take the time to read the Stickied FAQs.
:horse:

Bluethunder3320 05-14-2012 01:17 PM

i find it nearly impossible to throw a rod on a stock engine with no governor. the extra RPM isnt too much for it. rods blow because they get worn out or lack of oil most of the time.

i have revved the **** out of briggs and clones and they still run just as good as before.

Doc Sprocket 06-16-2012 10:53 AM

Governed Idle FYI
 
Copied in from another thread at several members' request-


Governed Idle FYI

The governor is a seriously misunderstood engine control system. For the greater good, here's a little FYI, an experience I just had. Might benefit someone in the future.

Where were we? Ahh, yes- the governor. Contrary to popular (mis)belief, the governor does much more than limit engine speed to 3600 RPM. Wonder why it's not called a "rev limiter"? 'Cause there's more.

The governor's purpose in life is not so much to limit RPM, but SET it. What's the difference, you ask? (I swear I just heard one of you ask that!) The difference is this. SETTING an RPM means KEEPING it throughout the workload. Let's use a lawnmower for example. You start the engine on your walkway and run the throttle up to max. The governor sets the engine to 3600 RPM, and there is no load (not cutting grass). As you move into the grass, the engine starts encountering a load. The governor allows a throttle increase to bring the revs back up to 3600. Cutting away, you encounter a thick patch over the septic tank. As the engine begins to bog and the revs start to drop, the governor allows the throttle to open more and bring the revs up to 3600. Cool? Great. Going around the corner thru that thick grass with the throttle wide open, you hit that bare spot where the dog keeps peeing. The load comes off the engine, and as it begins to increase, the governor closes the throttle to prevent over-revving and holds at 3600 RPM. Got it?

If you examine your external throttle linkage, you will notice that there is no direct connection between the hand throttle control and the carb butterfly. Governor again. The hand throttle does nothing more than alter the spring tension between the governor arm and the throttle butterfly. Setting the manual control to "Idle" merely alters the spring tension from the governor enough to allow it to SET engine idle speed. The idle adjust screw is the bottom end rev limiter in that it sets the baseline that the governor drops to. I told you that to tell you this:

I recently had a situation that some folks might misdiagnose- an engine that refused to idle properly. After a barrage of time, abuse, and adjustments, the chinese Kohler clone on my kids' kart would not sit at idle. The kart constantly wanted to take off with no throttle input. At a glance, the idle was too high.

Close examination revealed that the idle stop screw on the carb was not doing anything- the butterfly just would not rest against it. If I pushed the lever by hand, it would sit at idle RPM, but as soon as I let go, it would take off again.

I tried to adjust the external governor components to no avail. With the arm off the shaft, something just did not feel right inside the engine. I pulled the engine off the kart and tore it down. I don't even know how to describe what had happened inside, but the governor guts were all over the place- literally.

By some miracle, nothing was really damaged. Short version of the story? I epoxied the "press-fit" governor gear shaft back into the side cover and reassembled everything. I (re-)adjusted the external components, and wouldn't you know it? Idles like it just came outta the shipping container at 1310 RPM, and maxing at 4230 as measured by my optical tach. Food for thought.

Update- the kart is performing beautifully again.

r_chez_08 06-26-2012 06:47 AM

Apparently the governor can fall apart at 4900rpm
It is best to remove rather than bypass the governor.

Doc Sprocket 06-26-2012 04:49 PM

Funny- I've been suggesting that for quite a while... I've seen the internals on GX's, clones (and many other engines). It's pretty obvious what can happen. I suggest removing the throttle stop screw, and if that's not enough RPM, it's tome for surgery.

matman55 07-08-2012 03:05 PM

is it ok that i bypass the governor for short burst only? the main reason i bypassed it on my lawnmower is because i have really thick grass and before the bypass the blades would bog down and shut off the engine, so when i bog down i just incress the revs to get through the grass,im never doing this for more than 5 seconds at a time so what harm can it do?



edit- i also take it on the street and do the ocasional wheelie. whith the deck removed ofcoarse.

Nodroz 07-09-2012 03:47 AM

Quote:

Originally Posted by matman55 (Post 218190)
is it ok that i bypass the governor for short burst only? the main reason i bypassed it on my lawnmower is because i have really thick grass and before the bypass the blades would bog down and shut off the engine, so when i bog down i just incress the revs to get through the grass,im never doing this for more than 5 seconds at a time so what harm can it do?



edit- i also take it on the street and do the ocasional wheelie. whith the deck removed ofcoarse.

Well, I see 1 problem with this. If the governor inside brakes up because of the high rpm, then it can damage all your internals.

(Right?)

r_chez_08 07-09-2012 11:37 AM

Mattman, you will probably be OK, done this on my mini bike a few times.
Anything can happen though.

matman55 07-10-2012 09:22 AM

Quote:

Originally Posted by Nodroz (Post 218348)
because of the high rpm, then it can damage all your internals.

(Right?)

it not going to be spinning any faster, the blades will just have more cuting power.


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