gy6 starting problems By tonymc (Read 1,621 times)

[tonymc]

tonymc have a trailmaster challenger 150cc with 180 miles that wont start unless you use starting fluid, but still hard to start. getting fuel and spark, compression shows 90. even with low compression would it start with starting fluid, it will run a few minutes after starting it with starting fluid then shut down. installed a new carb, that didnt help. would low compression cause it to shut down like that after its running

[crwford]

my first question are you running high test gas also is this old fuel.

[jct842]

My question is why havent you adjusted the valves yet? Low miles, low compression, hard to start, and won't keep running. All the classic symptoms of valve gap = zero. As they get hotter the gap closes up to zero when there isn"t a big enough gap to start out with. Look in library to learn how to adjust.

[bostoncito617]

I bought a 150 on Craigslist with some really nice upgrades and mine has the same starting issue I definately think it's a value adj issue because it has 3k miles and I changed the carb,iridium spark plug,93 gas.....all it does it crank for awhile sometimes the headlights go on like its about to start and just shuts off nothing! As soon as I spray carb cleaner it turns right on😞 a scooter guy that knows alot on these saids the emmisions should be eliminated and that it will cause hard starts because the system they use former the chinese factory's sucks and it's just to make it sellable in the states lol I think Its called the egr or paar or maybe even pair lol 1 of those but if your valve cover has a u looking chrome loop then yours has the same system take it off!!! I hear its like a breath of fresh air it unleashes the clogged up arterys in this little scooter gd luck

[cyborg]

Valve adjustment time

[tonymc]

tonymc thanks for the replys. I did try to adjust valves already, I set intake to .004 and exhaust to .005. didn't really help any. I set the timing on the t mark and adjusted valves. when I put oil in spark plug hole my compression went over 150

[tonymc]

ive been running 87 octane gas instead of premium

[sillylittleboy]

I don't know if the regular gas vs. premium will cause this issue OR cure it. Once I read that I should use only premium gas in my scooter's tank, that's all I've ever fed it. The fact that my scooter uses very little gas (1-1/2 gallon tank) just makes it easier to keep feeding it only the premium grade fuel.

Of course once you do fill her up with premium, you'll probably have to burn through a little to get that fuel permeated throughout the fuel system.

Hey, it's a cheap fix and can only help.

P.S.  I think our premium is like 91-92 octane.

[tonymc]

that's not causing my compression issue or could it

[trashtruck12172]

it's possible with that low mileage and a compression jump the rings may not have seated yet and the motor needs to be broken in. i suspect compression may increase as the miles increase. also, was timing set on the compression stroke?

scooterdoc.proboards.com/thread/9155/easy-valve-set-ignore-mark

[crwford]

what was the reading before you added the oil

[cyborg]

He said it was 90,,,that's awfully low then the jump to 150 after oil was introduced in thru the plug hole....it may have been run dry ,,what's the oil level now?

[jct842]

As been mentioned many times before 87 is the right gas for these scooters. The chinese use a different method to measure octane and recommend their high octane which is roughly the same as our low octane. High octane has less energy and is designed to burn slower and a waste of money in these low compression engines.

The worst case with your low compression is you might have to slap a new set of rings in and hone the cyl or at least scuff it up some. It is possible as been said your rings haven't seated, rings are cheap.

[tonymc]

my compression was 90 to start with, after adding oil it went over 150. my oil level is good I set the timing like the video, set it on the t mark and made sure that big hole was in center between the 2 valves. I bought it with 75 miles on it and after putting another 100 on it, it started getting hard to crank. gonna go try to adjust valves again, if that don't work gonna try a new top end I guess

[crwford]

If you start with only 90 PSI and get 150 after oil test does sound like ring problem. But get it back the compression put plug in see if it runs take it for a run varying speeds done baby it see iff you can brake in rings that way after all nothing to lose right.