OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines Briggs and Stratton 450 series mower not stopping

Hi
I have a Rover mower with Briggs and Stratton 450 series engine and it does not accelerate or stop. Looks like an issue with speed control lever from the handle bar to the governor. Any help shall be appreciated. I have to unplug the spark plug lead to stop it.

Thanks

It sounds as if you are correct about the basic problem: the speed control cable is kinked at one end, or disconnected. If you post a series of pictures of the two ends of the cable and the surrounding mechanism, we can try to work out where and why it is happening.

thanks grumpy. shall upload tommorow.

uploading some pics ... looks like the small spring has come off from one end. not sure if it needs replacement or simply should put it back where one end of the long spring is connected. it feels really hard to move the lever on the handle bar.
also i would like to know how to figure out if this is US made or chinese.





thanks in advance

Your engine was made on 7 August 2007. It is 9 cubic inches (148 cc) displacement, is of the 30th design generation, has a vertical crankshaft and a Vacu-Jet carburetor, has plain main bearings, and has a rewind starter. Here is the operator's manual:
http://bsintek.basco.com/BriggsDocumentDisplay/msvtDR-K_ny7tH217FzoPu.pdf

Here is the illustrated parts list:
http://bsintek.basco.com/BriggsDocumentDisplay/18kvuIXSnfBhU7y.pdf

I'm told the Chinese Briggs engines have some ribs cast into the engine crankcase, which American Briggs engines do not have. If you take some pictures of the engine's crankcase from various angles, Joe Carroll or someone else who knows the answer will be able to tell you whether it has the ribs.
[/b]Post-Edit: that engine has Plant Number 51 in its Code. There is no such plant - that is an administrative center at Briggs HQ in Wauwatosa, Wisconsin. Briggs seems to have adopted a practice of marking engines exported from Chongqing in this way - you can pick them by them having a plant number in the 50s.[b]

The small governor spring sets the speed for the "governed idle" - your engine has no idle speed screw, and the idle speed is adjusted by bending the special bracket that holds the stationary end of the small spring. The large spring sets the engine speed whenever the speed control lever is above the idle position.

Here is the illustration from the workshop manual showing what your governor control should look like:


We need views of your governor control from directly above, and from the angle used in the workshop manual illustration. I think you can easily see where your idle speed spring should be attached, but at present I am unsure how your remote speed control cable is connected. It does not seem to be connected to the point shown in the workshop manual illustration. However even if it were not connected at all, you could still control the engine's speed, and switch it off and on, by using the speed control lever on the governor plate, circled in yellow:


Please confirm for us in your next post where the engine end of the remote speed control cable (the handlebar end of the same cable goes to the lever on the handlebar) currently goes. It looks as if it may be the cable end circled in red on the above photograph. I do not know whether that attachment point is part of the movable speed control lever, or is a fixed, stationary anchor point. Can you post pictures of that lever with the handlebar speed control lever in two positions, please: full speed, and stop. Then we can see how the lever operates.

Awesome information. Thanks heaps grumpy.

[Please confirm for us in your next post where the engine end of the remote speed control cable.It looks as if it may be the cable end circled in red on the above photograph.]

This is correct. The other end is attached to the red circle in your image. I do feel lot of tension while moving the handlebar speed control knob. Almost like it is going to break the lever.

[Can you post pictures of that lever with the handlebar speed control lever in two positions, please: full speed, and stop]

I shall attach more pics once am back home.

I am attaching few more pics I took today morning. Not sure if the shall be helpful but may help figure out where it was made.

A tidy-up item. Yellow squiggly line surrounds the idle governor spring, red oval surrounds the point where its free end should be anchored. The spring has to end up just the right length, to give the 1750 rpm idle Briggs specifies:

Thread revival here, but I'm having the same problem with my Victa Vantage with 450 B&S engine...

I changed the oil and put a new air filter in today and its running better than it was, but the throttle is still stuffed and I don't really understand why. Both springs are connected to where they are supposed to be according to the workshop manual diagrams posted earlier but still no control.

Once I've started her up, only way to get it to stop is to pull the plug or run it out of petrol so it is annoying... anyone have any ideas?

Are you saying it is difficult to move the speed control lever? If so, the cable probably isn't moving far enough to operate the kill switch at the extreme end of the speed range at the slow end.

Please confirm whether the problem is a stiff cable movement. If so, post some pictures of the cable. Most likely it is either a cable kink or lack of lubrication of the cable.

The speed control lever moves ok, the cable isn't kinked and I can see it moving the lever circled in yellow in this picture:


It does get stuck a little on the body at the "stop" end of movement but even if I push it all the way with my hand it doesn't do anything

I'll take the filter off again tomorrow and take some photos

From your description it sounds as the speed control lever circled in yellow may not be moving far enough in the reduce-speed direction for the kill switch to make contact. Take a look at the kill switch, which probably has one contact attached to the bent lever, and the other to the stationary plate that lever pivots on. See if the contacts are touching each other when you move the lever to minimum speed. That is what stops the engine: if they don't touch, it doesn't stop.

I think we need pictures of your engine's governor, rather than re-posting the previous pictures.

The best I can see through the dirt the stop switch is located in the circled area. The orange arrows indicates the two surfaces that must contact. If these are contacting and it still not stopping the engine you can take an ohms meter and check that switch contact is actually being grounded. If it is being ground then either connecting wire to coil is broken or the coil itself is bad. You can test if the coil is bad by connecting a good length wire the coil's stop terminal and ground it when the engine is running; it should stop it; otherwise, replace the coil. Just make sure you keep away from the moving parts.

Ok so I've given everything a clean and taken some photos. The first one is throttle fully open, second is fully closed and the third is how much further I can push with my hand.

Fully open throttle:


Throttle on stop:


Pushed further manually:


So if I push as far as I can (manually as shown in third pic) while its running, the revs will drop to an idle but not completely stop. The large spring seems loose if that is important but it appears to me that the throttle cable isn't pushing the levers far enough but even if it was, the engine still won't stop

Any ideas?

First, the large spring controls the engine speed when the engine is running above idle speed. The small spring controls the idle speed. Hence it is normal for the large spring to be relaxed at idle.

Second, the major kink in the cable inner near the governor's speed control lever, is supposed to be straight. That is why the speed control arm isn't being pushed all the way to idle. The kink may have been caused when someone tried too hard to push the control lever further, perhaps because the engine hadn't stopped.

Third, because it doesn't stop when you push the lever itself as far as possible in the stop direction, it looks as if there is a problem with either the kill switch, or the wire attached to the kill switch. As AVB said, if you have a multimeter ("VOM" in the US), check whether the contact on the moving arm touches the contact on the governor plate when you slide the speed control all the way towards slow. If you don't have a multimeter you have some extra work. Remove the cooling air cowl (top cover) from the engine and you will see the ignition module near the flywheel, at the end of the spark plug lead. Look at the module and you'll see a thin black wire running off to the kill switch. Trace the wire and see if it is connected at both ends: to the module, and to the kill switch. If it is properly connected, you'll need to check the module itself. You can do this by disconnecting the wire where it attaches to the kill switch, and with the engine running, ground that wire to a metal part of the engine. If the engine keeps running, and you're sure the wire is not broken internally and is connected to the module, your module is faulty.

In the third picture it is still not touching the stop switch by 5mm or more, brigg's from the factory have a cable tie around the throttle cable and the throat of the carb to hold it straight, best guess would be to straighten out that kink, strap the throttle cable firmly to the side of the carburettor and adjust the cable toward the front of the engine if neccecery.

Thanks Joe, that makes more sense - levers not touching the stop contact seem way more common than there being something wrong with the switch contacts.

Ferret, I suggest you do as Joe suggests and straighten the cable then cable-tie it to the carburetor. You'll have to hand-bend the cable inner back to straight as your first step. Once it is straight even when you are not touching it, it is time for the cable tie. It looks as if the cable tie has been broken or removed as the first step, then the cable inner was bent because there was nothing to keep the cable from buckling under load. There's a good chance there's nothing else wrong.

I've done some playing around, I started off by adjusting the cable to give it some more length and it is now hitting the kill switch and stopping the engine. There is no cable tie on mine so it seems that someone has removed it at some stage so I'll replace it and see if I can get the cable as straight as possible and adjust as required.

I've learnt quite a lot during this process as I've never done anything to a mower before except put fuel in so this has been a good learning experience for me. Thanks everyone for your help and advice

You are welcome ferret, you'll find there are many people on Outdoorking who enjoy helping those with problems. Come back any time you have a problem or a question.

I'll close this thread.