I've got a Briggs & Straton engine on a Rover Model 45 Reel mover. i'm having problem starting the engine and just want to find out what are the things i should check for. Please note that i recently did a thorough cleaning of the carburetor including the fuel tank and managed to use it afterwards so i don't suspect that i did something wrong reassembling the carb. First thing i suspect now is the spark plug which i haven't replaced for a while. I am yet to test it does spark but not so sure how to test it. My idea is to remove the spark plug and leave it connected to the ignition cable and see if it spark when i cranked it. Will this be right ?
Hi Shannon, That way will often only tell you that the coil is sparking, sort of tells you the plug is sparking but it is no guarantee, often a plug will spark in the air but not work under compression. If you are going to test the plug out of the motor it must be connected to the plug wire and the plug body must be held against some steel part on the motor
Thanks NormK for the advise. I did buy a new plug but to my disappointment, it still won't start. I tried testing the plug out of the motor whilst connected to the plug wire and i can't seem to see any spark. So it could be something else on the electrical circuit. Next thing i'll be checking is if all the wirings are still connected. How do you know if the plug wire are still good ? Any other components that i should check ?
In the past, if i couldn't get it to start, i removed the spark plug and put in a few drops of petrol and re install the spark plug. it has worked for me on several occassion..
Hi Shannon, this could be long and hard for you to sort out. Spark is simple to diagnose if you know what you are doing. I don't know what ignition you have on it without a pic or 2 to give us an idea. It can be a combination of coil/points or condenser or it may be fitted with an electronic ignition coil. We need more info as to what you have and pics should help with the diagnosis
I have attached some photos which i hope would help. I open up the carburetor chamber and noticed there's a little bit of fuel sitting there. It could be that i tried to start it up a few times. From what i can see, the plug wire is connected to this small device with a magnet. This device is in turn connected by a small black wire to the end of the throttle control (not sure what this is called. Shown in pic 0327).
Norm will get you sorted but something to try first. Looks like you have a lot of rust build up on the flywheel and magnets, these need to be clean or it will effect spark. Take the coil off, clean the flywheel magnets with emery til they look like bare metal and clean the coil pick ups as well, re fit coil, set air gap and check to see if you have spark, you might get lucky. The black wire is for the kill switch when you shut the engine off, you can disconnect this when checking for spark to eliminate the wire being the cause.
Hi Shannon, At this stage don't worry about the carby, no point if you don't have spark. The black wire from the coil to the carby mounting bracket is the killswitch so disconnect this from the coil and check again to see if you get spark. If still no spark I would say the coil is the problem.You could give the flywheel magnets a sand up and the face of the coil legs. Reset the coil gaps when you refit the coil.
It looks like i have a few things to do here but just need to clarify the parts you're referring to : :
1. Remove coil - which is the coil ? is this where the spark plug wire is connected to ? 2. Clean the flywheel magnets - I assumed the flywheel magnets is the rusted part. It must have rusted when i stored the mower just under the roof. 3. Clean Coil pick up - not sure where is this. 4. Set air gap - where is this gap. 5. Sand up the face of the coil legs - where are coil legs 6. is the coil gaps the same as the air gap mentioned by wce.
Sorry about all the questions as i don't have a parts diagram of where are all this and i'm not totally familiar with the terminology.
Thanks wce for the video. Now i understand which is the coil and flywheel. From the video, it looks like the air gap you're referring to is the gap between the coil and the flywheel. i do have a feeler gauge. Is there a specific gap that i should set it to. From the video, the gap was just set arbitrarily.
you can set the gap by eye after you have done a lot of them but I think from memory it's about 10 - 11 thou but anywhere close to that will do to determine if the spark has returned.
When you say 10 - 11, do you mean it to be 0.10 to 0.11 mm ? I'm asking cuz my feeler gauge range is from 0.05 to .0.50 mm. I've started cleaning up the flywheel magnets and the face of the coil legs. I just need to clean it up a little bit more and should be ready to reassemble.
Finally, i finished polishing the flywheel magnet and the coil legs. I have re-assembled them back setting the gap to 0.20 mm and have retested to see if any spark is generated. When testing it, i placed the spark plug touching the cylinder body and i couldn't see any spark. This is the part that i'm not sure if i'm doing it right. I also tried testing it with the plugs installed but also unsuccessful in starting it up. I've attached the photos showing how the flywheel and coil legs are and how i'm doing the test.
Hi Shannon, I believe you have done exactly as our Postie did this week, I gave him a Magnatron coil and he soldered the existing points wire to the terminal on the coil. This kills the spark. Those 2 wires need to be cut off and discarded. That terminal on the coil has only one purpose and that is to go diretly to the kill switch on the carby throttle bracket. Initially just cut the wire off and you should now have spark, then you can worry about the kill switch wire, it has no other purpose than to shut the motor down.
Norm, this is an original magnetron engine by the looks, not soldered on from old model. Quite possibly the spark was jumping 'down' to underneath the cooling fin.
Shannon, change the way the plug sits on the block and crank it.
As Norm said, disconnect the kill wire and give it a go
Hi Tyler, looking at the pic again it looks like the kill wire isn't connected. I can't remember what the story is here, is this another coil? all a bit hard because it has gone on for so long.
Time to celebrate fellows. I have made progress. As you guys have suggested, I disconnected what you call the 'kill switch' wire from the coil and after a few try, it finally started. I was already thinking that i might have to replace the coil but that appears to be not the culprit. i just had a problem now of how to stop it as it doesn't stop that quickly. Any suggestions ?
i now have to check what's wrong with that wire if there's a cut somewhere.
I just want to say thank you guys for all your hints and tips. Have learned a few more things about this mower.
Hi Shannon, it is so hard without seeing what is happening. I don't know where that wire is going but I am tipping it was for an old points system. That terminal wire has to go directly from the coil to the kill switch on the bracket where the throttle cable moves back and forth. If you look closely in that area you will find the original wire is still connected there. Cut that wire off at the crankcase where it enters if it is still there and extend this wire to the terminal on the coil. Either replace the wire or extend it whatever is easier for you
