OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines Briggs 3hp carb and magneto

Gday there! I have an old rover thoroughbred 16" that I have been fixing up for a little while now. I was wondering if any guys could help me out with some parts on the old 3hp Briggs.I can't get the carb to tune properly I manage to get it started on a rich setting and the lean it off to run smoothly, but after a few minutes it conks out and I have to start again with the turning the screw to the rich side. Could anyone help me? Also was it worth changing from points ignition to the electronic ignition? I do get spark, but it may be a bit patchy/unstable. Cheers! Also the model number is 80202 0635-01 76091503 thanks for any help!

Hi mate. I would recommend removing the breather casing and checking your valve clearances. The valves may be seating when coldm but as the engine heats up clearances could reduce causing issues.

Check the diaphragm & spring in the carby

Oh yeah I never thought of that. I know the breather casing, how do you adjust the valve clearances? I'm a pretty handy guy but valves is something I have managed to stay away from in the past. Cheers!

Oh that the fun to do and most likely you find that it might your problem too.

Requires removing the head so the valves can be removed if the clearances have closed and that is fairly common on L heads (Side Valves).
Once the valves are out you file squarely the valve stem to increase the clearances. To close up you either install new valves and/or grind the valve seats. Be carefully as you can over do it quickly. I usually go for max clearances as they do close up over time from wear of the valve face and seat.

Got to go a turkey hunter just showed up and I got to hid....

OK so I just cleaned and adjusted the point and condenser to .o45" and it seemed to run good first pull I let it idle for 15 mins and it ran smoothly, then I went in and had dinner and came back out and went to start it it ran for about 20 seconds and conked out. After trying to start it for about 10 minutes I checked to see if they was a spark. I pulled the plug out and rested it on the block.I connected my drill to the crank and kicked her over, there was spark! At idle speed so I wound the speed up to say somewhere in the mid range maybe around 1600 rpm the a loss of spark. So I reduced the rims back down to idle speed and the spark RE appeared... what could this be? And what parts do I need to fix it? Cheers jason

Not sure of the motor you have but you can usually fit a later coil on it and this then removes the need for the points.

Yeah I have seen that but I am unsure of the coil that I need, I called numerous mower shops and they all said throw the engine in the bin. Which I thought was a bit rude. "You know it's over 40 years old Don't you?" My reply was "yeah I do actually, and it will someday run for another 40" you'd be lucky to get 10 out of a new mower these days. all the mower shops with their throw away attitude. If it wasn't my grandpas old rover thoroughbred I probably would Chuck the motor in the bin. But it has some sort of sentimental value to me.

I can assure nobody cares anymore, so don't get offended by the mower shops, they don't have time to waste on old stuff, it's nothing personal, just the way life is these days. Is this motor a vertical pull, bit hard to tell, much easier if we had a pic. I'm pretty sure any of the horizontal pull Briggs motors have the coil you are looking for. Otherwise you could get a new condensor and points for it, but then the problem may still be in the coil you have. This is the advantage of the later coil, no points or condensor needed, just leave them in there and cut the wires off

Hi again, have you tried a new plug, or known good plug. If so, the symptons are typical of a faulty condendor/points. Sourcing a newer coil assembly (as mentioned by other members) will have inbuilt electronic ignition and rule out the ignition circuit. If you go down this path I would also recommend checking the valves clearances (no need to remove head) whilst your at it.

Gday, it has a brand new plug. I'm trying to find the coil which I need to convert it from points to electronic. 298502 is the original part number for the magneto, I don't know which electronic coil will fit mine my motor number is 80202 06531 cheers.!!!

I sure hope meant to be a metric measurement instead of inches.

The point gap on all models from 1919 to 1981 is .020� (0.51 mm). Points
should be clean and line up squarely.

The capacity of all condensers is .16 to .24 MFD.

Magnatron Ignition Coils 398593/395489/793281/793281/591420 are used on 2hp to 4hp aluminum block engines, such as 60000, 80000, 90100, Quattro, and Classic when converting form points to electronic version. Wire from points set to coil is then removed or cut as it interferes with the kill circuit. This list includes several numbers that have been superseded but these may be still around in NOS.

Problem is buying a new later coil is going to be worth a lot more than the motor is worth, try getting one from your local tip shop or hard rubbish, millions of those later Briggs out there
Another option if you can wait is this one, but it would be best if you put a pic here of the motor just so we can confirm what you have
http://www.ebay.com.au/itm/Ignition-Coil-For-Briggs-Stratton-591420-398593-496914-793281-793295-/131876318672?hash=item1eb470edd0:g:i00AAOSwygJXhgnA

So quick update, I managed to find a new Briggs coil which eliminated the points. First pull half way out, BOOOM! She fired right up! Cost me 40 for the briggs coil. Wam bam thank you mam. I think I may have destroyed the original coil as when I painted the engine I baked it at about 80 degrees in the spray oven. (I'm a vehicle painter) I did hear that they don't like extreme heat. So I think this may have been the case. I don't know how to post pics here but would like to put some up to show what I have done. I didn't take the original route of hammertone green. So I thought I'd try something different and I think it works. I know I'll probably get shot down as it looks nothing like the original. Cheers p.s. could someone tell me how to upload images from my phone cheers

I think your image needs to be uploaded to an image hosting site. For me it is Photobucket but there are others. Most times there also an image size limit like the site I manage where it is 600 x 600 dpi per image. The we use a limit for those who has smart phones are able to view the images easier.

To each his own when it comes to painting but as you there some that like to keep things as original as possible. To me a good paint job is better than something half done.