Hi, This is an offshoot of my earlier topic titled 'Scott Bonnar and unleaded fuel.' Before I knew what I was doing I purchased a 2nd machine to renovate. I am having problems so i thought I would start a new thread with an appropriate title so interested folk could find the subject easily.
Mower was sold to me as non running - seller said it was running before he left it outside in rain for a month.
I have changed oil, petrol and spark plug; cleaned the flywheel/magneto and armatures (which had a lot of surface rust) but no joy. Looks to me that there is no spark, which is puzzling. I attach photos of the the fly wheel/magneto and the wiring. Sorry about the picture quality - it was getting dark but I'm sure you guys have seen plenty of these.
G'day, your system is the older points and condencer system. i would almost bet that its the points giving you your trouble, becuase they get dirty and corroded easily. the first thing i would look as is the stop switch(if installed) and make sure its not too gunked up and there is no wires obviously worn threw or toughing. the easiest solution is to replace the whole magneto with a later electronic ignition system as they are much more reliable in the long run. another advantage is not having to remove the flywheel assembly to get to the points, which can become troublesome as you need a special tool to remove the starter mechinism (although i normally tap them lose with a hammer, but i would not recommend this). so try the obvious first then if you still have trouble ring a few mower shops and get a price on a secound hand electronic ignition coil (i wouldn't expect anything over $15 to $20). if they try to rip you off ill sell you one for $10 + postage (last time it was about $5) so see how you go regards jay
I agree with tezza - the first step is to check whether there is spark - though I wouldn't do it his way because it hurts too much if the system works. Remove spark plug from engine, connect plug lead, hold or clamp metal base of plug against cylinder head, and pull the starter. Watch for spark across the plug gap. If there is spark, tell us and we can go into the next steps (which are checking for compression, and for fuel actually getting into the cylinder).
Sorry, I should have been clearer but I was a bit crackered last night. I have risked the shock snd held the connected original spark plug and subsequently a replacement spark plug on bare metal of cyl head whilst cranking engine - no spark
Jay Thank you for your time and expertise. My lack of knowledge caught me out and now you have highlighted I can see the points/condensor on the parts diagram I have downloaded from the B&S website. I am happy to follow your advice re upgrade - presumably I don't need to worry about 'preserving originality' rather like classic cars which also have ignition upgrades so they actually go.
Forgive me, I don't know who I am typing to - do you sell B&S parts and maybe Scott Bonnar parts. I ask because there are a few more bits I need and I have another B&S engine on a slasher wating in the wings - I would prefer to buy from someone on the website.
Presumably I need to get the flywheel off now anyway. You mention tool to remove starter mechanism - is that the splined rod shown in my first picture that the pull cord housing slips over. Is the special tool some kind of universal puller that I could get from Supercheap - if not could you expand on 'tapping it loose'
Oh, by the way the 'stop switch' which should be on the cyl head has been removed and the spark pug connector on the HT lead has a rubber cover on it. All looks good. Regards
Hi Brian, Grumpy,(who is very experienced with all things B&S) will surely jump in here and give you good advice about flywheel removal, and what to check re: points, condenser etc... Re: Scott Bonnar parts; Bruce is uploading parts to the Outdoorking online store all the time..(click the button in site links in the left hand navigation menu) and follow the prompts and have a look.
Jay (mowernut) has given you good advice about the electronic module, you could purchase the one from him...Just send him a PM to sort out the details
Please do not PM me asking for support. Please post your questions in the appropriate forums, as the replies it may receive may help all members, not just the individual member. Kindest Regards, Darryl
First, Outdoorking has no staff. Bruce owns and runs it, and various hobbyists come here for entertainment and a sense of satisfaction. You send a PM by clicking on My Stuff at the top of the page, then Messages. You can send a PM to any registered member. You have verified that you have no spark, and you have no killwire (your engine originally had the sparkplug shorting device, which preceded the killwire). If you had a spare coil it would be worthwhile trying it rather than removing the flywheel to access the points and condenser. To remove the flywheel take off the piece of perforated metal behind the splined over-running clutch at the center. That reveals the larger-diameter clutch at the back of the splines. This unscrews from the flywheel. You need a device called a C-spanner but as mowernut has said, some desperate individuals sometimes apply a soft punch to one of the slots the C-spanner should engage, and tap the punch anticlockwise to undo the clutch. Be careful - several balls will fall out, and you'll need them when you put it back together. Now you can access the flywheel retaining nut. Unscrewing it requires either restraining the flywheel, or using an impact technique. When the nut is off, you still have to deal with the taper the flywheel is on. The proper way to do this is to make a simple puller out of a small piece of steel plate, but the screws required (to screw into the flywheel) have American threads. Desperate people sometimes avoid this problem by treating the flywheel as an automotive ball joint: you place a very heavy metal object on one side of the flywheel, and whack it sharply with a largish hammer at a point directly opposite. It should then pop off the taper. Once the flywheel is off, the points and condenser are accessible behind a metal cover. If you need more detail for some of this, just ask. Here is a quote from the B&S engine manual:
NOTE : To remove small cast iron flywheels without puller holes. Support the flywheel with a gloved hand, exerting an upward pull. Using a rawhide hammer, strike the outside rim of the flywheel with a sharp blow. Several blows may be required on an extremely tight flywheel.
i wouldnt reccomend tapping the starter cluctch off, its made of aluminum and will break easy.
Instead get yourself a length of wood and some longish bolts, and make a removal tool yourself. There is a video floating around this site somewhere that shows you how to remove the flywheel, and the fella in it uses a home made steel tool, but i reckon that a wooden tool would work just as well.
Many thanks Grumpy - as you will have gathered I am new to the Forum and I didn't appreciate the setup. I will escape to the shed as soon as I can and follow your instructions. Regards
