OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines 12 hp model 281707 choke governor connection point

Hi,
I have a 12 hp. Briggs and Stratton engine model 281707, type 0412-01 on a craftsman lawn mower tractor. I have included pictures of the choke link cable and the governor plate that it somewhere attaches to on the backside. I connected it through the hole on the pinion plate but the choke didn't work properly. Briggs sent me the maintenance manual but it des not show the connection on the governor plate. Any assistance would be appreciated. Thanks




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Hi Ali, welcome to Outdoorking.

Here is a thread we had on this subject back in December 2012:
https://www.outdoorking-forum.com.au/forum/u...amp;Words=rack&Search=true#Post42644

Here is the Illustrated Parts List for your engine:
http://bsintek.basco.com/BriggsDocumentDisplay/Z6ntzHVJ1DajI.pdf

The choke link is shown on page 3 of 12 in the IPL, and identified as Item 216. First, is your link the same shape as the illustration? In the previous thread, that was the problem.
Here is the illustration of how it assembles, from the B&S manual (page 132 of 338):


It shows Item 216 as going behind the governor plate to attach. I can't find an illustration that shows the attachment, but I'm wondering if it attaches to the hole I've circled in red on your picture. (I've had to use File Manager for some reason, or the picture appears as black. Just click on the Attachment below.)

Please report back on whether connecting the link that way is successful, if possible with a another picture or two. Our archive badly needs a clear illustration of this, since it is obviously a problem people are having.

Thanks Grumpy for your quick response. I also thought that the linkage went through the hole, but when I hooked it up that way it just didn't seem to work properly. I will give it another try in a few days. Spring is here and the grass is getting long so I will hold it by hand until I have time to play with it some more. I will update when I find the answer. Thanks again.

Thanks Ali. That end of the 216 link looks as if it is designed to work as a lost-motion device, which it can't do if it goes through that hole, but I can't see where else it could attach. Could we have some more, clearer pictures of the back of the rack and pinion mechanism please, to look for other possibilities? It seems clear from the Briggs illustrations that the link attaches behind the mechanism, somewhere.

Hey Grumpy. I think I may have found how that linkage works. There is a slot on the plate and the linkage just sits in that slot. When the choke lever is moved to the choke position , an actuator arm on the rack assembly goes through the horseshoe, makes contact with the end, and then pulls the choke linkage to activate the choke. When the choke lever is put into normal run, the arm is no longer in contact with the horseshoe and the choke returns to normal because of the spring on the choke plate. Sorry for the long winded description and the non technical explanation. A picture is worth a thousand words, so I have included a picture. Now on to tackle a bigger problem. A compression test only giving me a reading of 30 psi.

Well Ali, you've found the lost motion device that I was looking for, and its purpose is just as you have described it. Much more complicated ways of doing the same thing were used on car chokes back in the days of automotive carburetors.

If you could take a picture of the entire governor plate, with choke link correctly installed, from a position perpendicular to the plate, like the second-last picture in your previous set (the one with your thumb featured prominently), I think it would be very useful to other people in the future. We've never established a decent archive on the rack and pinion governor control.

The low compression pressure is very likely to be due to one of three things:
1. Blown head gasket.
2. Terminally worn piston rings.
3. Leaky valve or valves.

I suggest you begin by putting one spoonful of engine oil into the combustion chamber through the spark plug hole, then immediately repeating the compression test. If it makes little or no difference, you can cross off worn piston rings from the list. We can then go on to investigating the other two mainstream possibilities.

Hi Grumpy,
Thanks for all your help. I just saw your response after everything was back together, and you nailed it. It was a blown head gasket and both valves needed to be adjusted. I didn't have a spring compressor so I made a shim and placed it under the keeper with the valve open and then rotated the flywheel so that I could get a gap between the valve stem and the push rod. Then with a small file I filed it a bit at a time repeating this procedure until I got the proper gap. Put everything back together started it up and Bingo started great. Compression test was up to 100 psi. Unfortunately I didn't see your response until everything was back together so I didn't take a picture of the plate. if you combine the pictures I have sent it is possible to see how the choke link is tied in. If I have to take it apart again I will definitely take more pictures for the group, otherwise unless you really need it I will leave it as is and move on to a tiller and a trimmer I have been meaning to fix.

Thanks for giving us a final report on your project, Ali. It should all be good. You didn't adjust the tappets in a way that would enable the Briggs guys to preserve a neutral expression on their faces - they'd be wincing heavily - but it should work satisfactorily nevertheless. Because the valve stem is very hard - harder than the tappet - I think nearly all of the metal you removed will have been from the tappet, where it is supposed to come off the valve stem, by grinding it. Most of our members don't have valve spring compressors that will suit a side-valve engine, but most find they can lift the spring with their fingers and push the keyhole-type spring retainer across so it falls off. When it comes to reassembly, one popular technique is to use a pair of cable ties, positioned opposite each other, on each spring. You compress the springs by pulling the cable ties tight, then when the keyhole retainer is in place, you just cut the cable ties and pull the pieces out with pliers.

I explained that for next time, there is no need for further work this time. As long as you ended up with the top of the tappet parallel to the end of the valve stem, what you have done should work, it just limits the number of adjustments you can make before you have to invest in new tappets.

Hi Grumpy,
I did in fact file down the valve stem. I watched a you tube video on how to do it. (What a great resource). It was a small flat fine file so it took a while. I didn't realize that I may have been able to remove it without a tool. Thanks for the tip. Don't ever recall the engine starting and running so good.

That is interesting Ali, thank you for clarifying. I'm surprised that you could make any impression on the valve stem with a file, but I gather the exercise is not expected to be very good for the file, and if it works, the problem is solved.

The side valve Briggs engines have many good qualities, and among them are light weight, low cost, easy starting, and fairly smooth running. Until the early 1980s they were probably the smoothest-running small engines around. Since then the smoothness of their running has been overshadowed by the OHV Hondas, but at considerable cost both in money and weight. The old Briggs engines still have a valued place in actual use, as well as in mower history. Many people enjoy the ease with which they can be repaired, and the readily-available, low-cost spare parts. I think we still have more Outdoorking members repairing Briggs engines than Honda ones.

I'll close this thread, as we always do with completed projects. If you are looking for any help on your other repair projects, you are welcome to start new threads in the appropriate Outdoorking forums.