MegaSack DRAW - This year's winner is user - rgwb
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Advice sought for a problem with my sons' Scooter.
It's a 2-stroke and I've recently put a new oil pump in it(amongst other things, as it has been used by Son No.2 for the last 3 years).
Passed it's MOT etc and rode ok, but it nipped up on my on the way back. It's a hill so I thought maybe I'd not adjusted the pumps' cable properly.
I took the head off too and found a few marks on the barrel but when I took off the exhaust I could see markings on the piston.
So bought a new piston and rings.
Put those in and adjusted the cable so as soon as the throttle is turned it activated the pump.
Reassembled and after a few turns it started.
Went for a spin and it nipped up again, but only under 'load'. It'll start and run fine, but still nips up once past 20 and/or rise.
Any ideas?
It might be Too much oil making the mixture lean, there are usually marks to line up on the oil pump to make sure it opening at the right time. If it's starting too early that might be your problem. It could also be an air leak somewhere.
Empty the oil, Pre-mix the oil and fuel directly into the tank and see how it runs..
What's the plug colour like?
I'd premix as tymbian suggests.
tymbian has the answer.. pre mix the oil and run a tank full through, 70ml per 5 litres of juice would be ok no probs and its the pump nips up and your running lean and or hot..( ignition..)
Sounds like an air lock in the oil feed to me. Have you bled the oil pump?
It was running pre-mix before, as it had failed, and my lad lives away so went with the easiest fix option.
[i]Sounds like an air lock in the oil feed to me. Have you bled the oil pump? [/i]
No..., how?
This advice is going back 30 years, but there used to be a bleed screw you took out and waited till oil came out of the hole and then replaced the screw.
Oil in the tank and working fine...
A pal suggested that the oil pipe into the crankcase might be blocked too.
Will take it apart next w/e.