briggs 11hp problem

[whmtd]

I have recently acquired a wheel horse b111 it was running fine when I first got but two days later it will not start. At first I thought it was the carb as I adjusted it whilst running because it was really rough but after adjusting it to the original factory settings and making sure fuel is getting into the cylinder I discovered that the spark is very weak indeed so weak you cant see it if you hold the plug in the ht lead and only just see it if you put a screw in the ht lead and hold it againsed the block (earthed) On cars I would say it was the points or condenser but would this have them (1979 build date11hp brigs electronic? )If so then is it worth taking it to the garage as it has no cutting deck and I only paid ｣50 for it. any suggestions thanks

 

[EngineMan]

If you need to know if it has points with condenser, post up the engine numbers.

Believe engine for that is a B&S 252707 if so no points with condenser, part number 398811 Armature Magneto

 

[whmtd]

Thanks for the reply I have been working on the mower this morning and it does have points and a condenser although that is the model number I have cleaned the points and I am now trying to find out the correct .Do you know if there is a standard gap for these engines

 

[Rivets]

Standard armature air gap is .020. EngineMan will have to convert that to metric, as I'm not a math major.

 

[EngineMan]

Standard armature air gap is .020. EngineMan will have to convert that to metric, as I'm not a math major.

.020" = 0.5mm

 

[EngineMan]

This maybe a little late......but........

 

[whmtd]

Hi thanks for all your help :smile: the points look ok and I have cleaned them and re gaped them but still no luck what is next? can you test the condenser? which would be more likely to be causing the problem the ignition coil or condenser?

 

[EngineMan]

If you contacted B&S tech help line with queries including asking what the magneto coil resistances should be – they will say “Sorry but there are no published resistance readings for our ignition coils”
A Mag Coil primary (The wire connected to the points) has a VERY LOW resistance. It is about 1/2 OHM with the engine block as the common point. It is the rare ohmmeter that can tell the difference between the resistance of the coils primary and the ZERO resistance of a closed set of points. You need to also read the resistance of the spark plug wire to engine ground. It should be in the Kohm range. It can be as low as 4 Kohm to as high as 13 Kohms. No reading is normally BAD but not always. At best using a ohmmeter to check a mag coil is better than nothing test BUT there are ISSUES. THE ONLY TRUE TEST OF A MAG COIL IS ON A MAG COIL TESTER.

How to test a condenser. they should measured out at around 0.22 micro Farad

How To Test Lawn Mower Condenser When Troubleshooting Lawn Mower Electrial Problem - YouTube

 

[whmtd]

hi I have tested the condense as best I can but I cannot do it properly as I only have a cheap multi meter without the correct settings. is it possible to buy an electronic ignition upgrade kit?

 

[EngineMan]

Best to ask at your local shop, but if it is the B&S 252707 then part number 398811 Armature Magneto is the one fitted to that engine, but you better ask before buying.

Where in Wales are you..?