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Phbh tickover

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Phbh tickover

Postby gp200ts1 » Wed Jun 20, 2018 11:48 pm

Setting my carb back up after a rebuild and I can’t get the engine to tickover on the screw alone, I have to adjust the cable to get it ticking over. Any ideas what could be wrong. It’s an avanti tt3 and I’ve done over 4000 miles on it before rebuilding. Done a leak down test so no leaks but I can’t see why the tickover screws doesn’t work.
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Re: Phbh tickover

Postby MickYork » Thu Jun 21, 2018 6:52 am

choke sticking, air filter needs cleaning, muck in jets, timing too retarded, stuck ring, etc, etc.......
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Re: Phbh tickover

Postby Rich Oswald » Thu Jun 21, 2018 12:36 pm

Usually after a rebuild you get a slower tickover due to the fact that everything is less worn and the sealing is better. Don't really think anything is wrong, you have merely taken the slack out of the cable.

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Re: Phbh tickover

Postby Knowledge » Thu Jun 21, 2018 1:04 pm

I have had issues with PHBH carbs where the screw-in tick-over adjuster doesn't actually do anything. Either the "point" is too short, or the external spring is too long.

It is not wrong to adjust the cable to get a tick-over. The screw AND the tightened throttle cable are doing exactly the same thing, by lifting the slide to allow more air beneath.
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Re: Phbh tickover

Postby gp200ts1 » Thu Jun 21, 2018 2:30 pm

Thanks guys it seems to be a bit different with a different slide. Still a 40 but the screw moves it up a bit more. Choke is fully closed as I set it so full lever movement opens it half way. Carb cleaned and blown out, timing still at 17 btdc and new rings fitted. I’m happier now the screw does a bit so I’ll run it again as usual.
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Re: Phbh tickover

Postby bolzenanker » Fri Jun 22, 2018 9:09 am

I've had a slide worn away on higher mileage carb, the tickover screw had worn a little groove in the slide making it ineffective.
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Re: Phbh tickover

Postby Norfolk » Fri Jun 22, 2018 10:22 am

That's interesting to know you have had problems with the idle screw wearing a grove in the slide, mine is exactly the same. I have done nothing with it using the theory that if it was replaced the same thing would happen.
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Re: Phbh tickover

Postby bolzenanker » Thu Jul 19, 2018 3:07 pm

Actually, I have just replaced the 40 slide with a 45 and upped my pilot and I'm now thinking the 40 was too rich and may have been the reason I was struggling to get a tickover. Who knows with these pesky scooters?!
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