Briggs ES45 just will not start!! advice please.

[mowerman]

Briggs ES45 just will not start!! advice please.

Hi everyone,

I have a McCulloch Elite 47 PDE lawnmower with an electric start Briggs and Stratton (looks like a quantum engine) ES45. Here is the problem:

. Throttle lever in correct position to start
. Push primer bulb 3 times as usual
.Turn the key engine turns over lovely, occasionally tries to fire.
. Have drained the fuel and replaced with fresh
. Changed plug and gapped for a new one (same make as what engine run with)
. At one point it backfired through the exhaust

. Had the carb off and cleaned it totally but it did not have any signs of dirt in
. When I remove the plug, it is wet. So tried starting without the choke (after pulling the engine over a few times without the plug) Have also tested the spark and it is good. Prior to removing the carb, I put a small shot of neat petrol in the plug hole, absolutely nothing, not even trying.

When I removed the pull start top to make sure everything was in place a small spark appeared as the steel cover was drawn away from the engine block. I wondered if this was an earthing problem and disconnected the battery. Trying to start the engine by hand proved no better.

There is good compression as it can be started by pull cord or electric start. Very odd and I'm out of idea's. The model engine number is 12770

[sally wright]

Dear Mowerman,
have you checked the oil level lately? Some machines will not start if there is not enough oil in the resovoir. If everything else was working prior to this failure to start then this may be the problem. If this is not the fault then there may be a problem with the piston rings, in which case it will involve a trip to the lawnmower A & E.
I expect Clive will be along soon with more valuable advice.
Regards Sally Wright.

[mowerman]

Hi Sally,

thank you for your input. Good point, I'll check and report back. Would there be a sensor / switch to activate this perhaps?

[FelixLeiter]

The condenser, perhaps. If the condenser's failed, you'll still get a spark, and a bit of life when trying to start it. But of course the timing will be out, which is a hinderance to it running.

[mowerman]

Well, looking on a few forums it seems to be that the coil is suspect. I'll try that and report back. If anyone else has any input please feel free.

Thanks so far.

[oldherbaceous]

Afternoon Mowerman, with you mentioning a small spark when removing the cover, i was wondering if there could be a wire that has worn through somewhere, or even the H.T lead shorting out. Just a thought....

[mowerman]

Yes, thank you for that. I removed the battery to see if that made a difference but it didn't. All the loom is in great condition. There is no condenser either as the coil works with the magnets spinning past on the flywheel. I wil try changing the coil to see if the spark is better but with a coil I would have thought it either worked or not as it is a wire winding? do they break down slowly I wonder?

[John]

Hello MM
One possibilty, though not likely, is that the flywheel has moved slightly on the engine shaft. This will happen if the engine comes to an abrupt stop say when you hit something. The flywheel key may have sheared. If this happens the spark timing is then wrong. Everything appears to be working and you have a spark but the engine won't fire up because of the timing problem.
If all else fails to sort out the problem then you could investigate this. The shaft key is not that difficult to replace.

John

[mowerman]

Hi John,

Thank you for your valued input, greatly appreciated. I will check that as a matter of course. All findings will be posted back on here. Hopefully they will help others.

[mowerman]

ok everyone, here is the long awaited update, The keyway is intact,

Elite-47PDE-flywheel.jpg (28.56 KiB) Viewed 8719 times

but looks out of line with the cut out in the shaft. I would have thought if the keyway moved it would have broken whereas this looks like it has slipped if that's possible? this crank from the correct parts list does not have the slot cut in the top of the shaft which makes me think the keyway has it's own cut out further down the crank?

Keyway intact

Elite-47PDE-flywheel crank.JPG (12.03 KiB) Viewed 8719 times

mower still backfiring through exhaust. Is it possible the exhaust valve needs re-seating / grinding back in ?

[peter]

I think if you take the flywheel/magneto-cover off you'll find you have two slimline keys instead of a single well fitting one.

It wasn't put on snugly enough previously and has been able to shear the key.

[John]

Hello again MM
When you remove the flywheel take great care. I don't know about your particular engine but many of these small engines have cast iron flywheels so don't whack it too hard when you take it off - cast iron is surprisingly brittle. It should come off fairly easily as its on a tapered shaft. Use a block of wood between the hammer and the fwheel or better still a rubber hammer.
New keys are easy to come by. The flywheel and shaft should be fine as the key is designed to shear under any stress.

John

[mowerman]

Hi to both of you, thank you very much for a speedy response. I can see the situation now. I thought the keyway was a steel one but it turns out is is an alloy (net research). I will make the removal tool and order a new keyway. I'll put the pictures on here for everyone to see and for future reference.

Greatly appreciated. Thank you.

[Ricard with an H]

I've had this happen, not on a flywheel. On the blade-boss, because I didn't lift the machine as I started it the STEEL key was shredded and the resulting steel particles embedded the two halves of the key into the keyways.

I'll never do that again, not with a six horse engine anyway.

Thanks for sharing and it'll be about time to remind ourselves how we put away our two stroke engines, Sally-style.

Another thread.

[mowerman]

Hi everyone, thank you for all your input. Now, here are the pictures of the saga and how it turned out:

The flywheel was not threaded so I had to tap the two holes. For reference, the size used was 0 (zero) BA thread.

I made the flywheel puller, removed the flywheel and it revealed two halves, neatly sliced.

Replaced the key way and re fastened the flywheel down. Sure enough http://www.youtube.com/watch?v=9CFU8tZm2-g&feature=youtu.be

It lives again. Thank you to everyone for your input, greatly appreciated.