yet another no start

[Deleted]

if the timing marks are lined up....it has spark, compression and fuel it should run.

[Deleted]

you said weak spark..what makes you say its weak? when checking it in the dark is it a fat blue (hot) spark or a thin yellow (cold) one?

[darkdragondsm]

its def blue spark, but as in not enough fire. i do know any kind of spark "should ignite.

as for timing marks, if timing was off, i should not be getting this high of a compression. i will take a picture of it all later on to show.

[trevvor]

my moped is doing the same thing i replaced starter, starter clutch and belt and cranks but on the 4th stroke it stops then wait a second then it cranks again im truly lost

[Deleted]

Apr 30, 2012 20:23:34 GMT -5 trevvor said:

my moped is doing the same thing i replaced starter, starter clutch and belt and cranks but on the 4th stroke it stops then wait a second then it cranks again im truly lost

We are finding out that not all 139qmb starters are created equal. I went through a system 100% both mechanically and electrically. I even doubled the wiring and put in a booster battery.

Posts 38-42 have to do with what i did with the starting system:
49ccscoot.proboards.com/index.cgi?board=builds&action=display&thread=3060&page=3

I finally found some high quality starters like are on my new 72's that i used on the above bike which now cranks without the booster battery:

www.ebay.com/itm/YAMOTO-STARTER-MOTOR-MOPED-SCOOTER-GY6-50CC-/260994104870?pt=Other_Vehicle_Parts&vxp=mtr&hash=item3cc475fe26#ht_2088wt_1017

That is not a standard replacement starter it is an excellent quality aftermarket one. If your electrical system and engine are in good order that starter will turn even a tight 200psi 82cc over with ease.

[trevvor]

so what can make it run perfect then the belt shreds i was still able to start it a couple days later then i stopped messing with it for a month or so then i put it together and now it wont start please help me im stumped

[Deleted]

1) a compression test
2) if it passes that, a new unsealed quality carb
www.ebay.com/itm/170769236151?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649#ht_6748wt_778

[darkdragondsm]

ok. its all assembled again. yet still a no start.

replaced entire fuel system; carb, fuel line, filter, regulator pump, int manifold, fresh 93 octane.
new spark plug (again)
new gates belt

when i crank, you can see the fuel flowing into the carb through the filter.
i sprayed cab clean through the vacuum nipple on the manifold to try to get a pop, and nothing. i tried, just about everything. and still a no start. already invested $200 on a $100 buy.

[Greg]

What was the psi from the compression test?

[Deleted]

May 11, 2012 11:13:05 GMT -5 Greg said:

What was the psi from the compression test?

:popcorn:

[darkdragondsm]

175psi

[Deleted]

it should be running then. Compression OK......mechanical timing.....?...fuel delivery...?...spark..?....(you want a thick blue spark not a weak yellow one).

[darkdragondsm]

May 11, 2012 20:02:32 GMT -5 darkdragondsm said:

175psi

just want to say whoops and i'm sorry. i forgot to turn the ignition switch to the on position on the steering... :beatup:

i got it started and running.

but now another problem. there is some weird noise coming from the belt area and under the engine cover...

will take video of it tomorrow.