HELP! Birmingham Scott won't start ??

This topic has 61 replies, 17 voices, and was last updated 8 years, 12 months ago by Deleted User.

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12th April 2014 at 6:43 pm #3666

Russell
Participant

I have just finished putting our ‘58 Birmingham Scott back together after a piston seized last year, and am having a few problems starting it. I’m getting a spark from both plugs, and the left plug is “wet” after attempting to start it, but the right plug looks dry. The carb is also leaking petrol, which it didn’t do before. I’ve stripped and cleaned the carb, but it all looks okay. I get the feeling the two problems are related, has anyone any suggestions?

12th April 2014 at 9:38 pm #12213

Deleted User
Participant

just started mine after 20yrs of sitting around, You might make sure the idle mixture screw is in place, that makes leaks and hard starting, don’t ask me how I know 🙄

28th April 2014 at 1:48 pm #12214

Russell
Participant

Anyone any other suggestions ?

28th April 2014 at 3:03 pm #12215

dave bushell
Participant

Try running a little oil down the bores – that often improves the suck and blow initially. You could also open the throttle fully and blow in a short blast of WD 40 into the carb, that often gets them started. Finally, make sure that your spark plug leads are not crossed over – that has caught many an owner out!
Dave

28th April 2014 at 4:33 pm #12216

Russell
Participant

Hi, thanks for that, I’ll give it a go, any ideas why the carb would be “leaking”, i thought the needle might be stuck but it seems okay, what else could cause the carb to leak petrol ?

28th April 2014 at 4:39 pm #12217

dave bushell
Participant

They all tend to do that with the petrol on and the engine not running. You could try rotating the float chamber toward the engine a little bit – that lowers the effective float height.
Dave

28th April 2014 at 4:49 pm #12218

Russell
Participant

Okay thanks, it didn’t leak before, but maybe I never noticed as it started okay so was never sat with the float chamber full and not running.

19th May 2015 at 11:21 am #12219

Russell
Participant

We still haven’t managed to get this started ! There appears to be a strong spark, the plug leads are correct, there is fuel getting through, but its not firing even when trying to push start (apart from the occasional bang), I’ve tried a different set of plugs (not new ones though), but to no avail !

Is there something fundamental here we’re missing !!

19th May 2015 at 12:07 pm #12220

BRIAN MARSHALL
Participant

All 38 degrees downdraught Scott carbs dribble petrol after the tickler button has been operated because that puts the petrol level above the primary airway. It stops as soon as the engine is running, and is nothing to worry about. Screw the primary air screw fully in (gently !), and then unscrew it 1.5 turns for an initial start up. Fine adjustments can be carried out later.
Have you tried switching the plug leads over ?
Also check that you have crankcase compression. Remove the spark plugs, open the throttle fully, no choke, and with ignition OFF, and petrol OFF, turn the back wheel forwards with the bike in top gear. You should hear a ‘plop’ noise twice per engine revolution, like a cork being pulled from a bottle. If you do not hear this noise it is likely that the cylinder base rings are defective or missing. If you have to renew them only use the latest ethanol resistant ones. Ian Pearce sells them but I don’t know the spec of the Spares Scheme ones. Perhaps someone can comment on that ?
Brian

19th May 2015 at 8:32 pm #12221

Deleted User
Participant

Hi all, I once spent a whole day trying to start a Brum ,newly “rebuilt” by its new owner. The fault when we eventualy found it was the PISTONS FITTED BACK TO FRONT!!! Migth be worth slipping off a transfer port to make shore their right. Regards Geoff.

20th May 2015 at 3:30 am #12222

Deleted User
Participant

@Geoff Case wrote:

Hi all, I once spent a whole day trying to start a Brum ,newly “rebuilt” by its new owner. The fault when we eventualy found it was the PISTONS FITTED BACK TO FRONT!!! Migth be worth slipping off a transfer port to make shore their right. Regards Geoff.

When you look at them through the port how would you know?

20th May 2015 at 8:46 am #12223

BRIAN MARSHALL
Participant

The steep, concave shape face of the piston deflector should be facing you when you look through the transfer port. Over thirty years ago I bought one of Albert Reynolds’s creations, an AER, as part of a job lot of mainly Scott stuff, and the engine wouldn’t turn over. The pistons were in back to front ! I sold it to Dave Richmond, who successfully restored it.
Brian

5th July 2016 at 6:15 pm #12224

Russell
Participant

Had another day trying to start this with no success, we’ve tried all suggestions but none seem to help. When trying to bump start it, it does cough and fire but wont run. We’ve got a spark, and fuel (the plugs get wet), timing is roughly correct, and we’re pretty sure the plug leads are the correct way round (as when it does fire with them swapped it seems rougher).

We’ll double check everything again tomorrow, but has anyone got any other suggestions as we’re getting very frustrated 😡 If there is anyone in the local area that could call in and take a look at it, we’d be more than happy to pay for your time.

Cheers
Russell

5th July 2016 at 8:35 pm #12225

Deleted User
Participant

Are you sure on timing, normally if the leads are on the wrong plugs you will not get it trying to run, you get a bang from the exhaust because it’s trying to fire when the exhaust port is open. Last weekend at Cadwell park one of the guys couldn’t get there Scott to start off the kickstart they always had to push it, I checked the timing and although set by an “expert” it was wrong. I adjusted roughly at fully advanced and the piston at just less than 5/16 btdc and the points just opening, it now starts first or second kick. He has now gone home to set with correct tools I e measuring equipment. Not sure if your timing is the same measurements or not but I’m sure someone will comment if you don’t know, I take it yours has a distributor fitted? Have you timed it on the correct rotation ??? Good luck for tomorrow. Kev

5th July 2016 at 9:46 pm #12226

Deleted User
Participant

If all fails tomorrow give me a call, I should be finished late afternoon. If you where closer I would come round, but it’s a bit far. Just so we know, when the piston failed did you completely strip the engine or just barrels and crankcase doors ?? Kev. (Editor, phone number as per Yowl)
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