4 stroke roketa running issue

[odinxxix]

ok heres the scoop. neighbor brought this over and asked to get it running. so it idles great! but while tring to give it wot it dies out but soon as i let go of the throttle it returns to idle. plus while at wot it will die out then back,die out then back. i checked for cracks,broken seals,cleaned carb,adjusted valves,checked throttle cable, adjusted the a/f screw and idle screw. its really starting to erk me. any suggestions? all are welcome besides blowing it up which i want to do anyway

[Saved]

How clean was the carb? Was it gummed up? Check the fuel filter, tank, and fuel lines for debris. Check the airbox as mine will always bog down / die off at WOT when there is something wrong with the air box.

[odinxxix]

actually when i got it here the carb looked real clean but i did it any way. the air box seems to be on there good. i took out the filter in just i guess a random thought that it might be starving for fuel but nope. but ill check again. the fuel filter isnt plugged and lines are clear. tank looked clean well what i could see. he told me the gas is about 6+ months old. but it starts on the first kick and idles like new.

[Saved]

Maybe it's a choke issue?

[odinxxix]

uh where do i find that? im new to the 4 stroke scoots. all of mine are 2 stroke.

[Clivester]

Whats the model and cc's of the Roketa?

You could have a carb with a bad CV diaphragm. Try looking into the intake without the airbox tube attached - one of those dental type mirrors often helps since the carb faces directly backwards under the seat pan. Gradually increase the throttle and see if the throttle slide rises at the same rate. If not, the throttle diaphragm may have a hole or is not seated properly. You may need to partially cover the inlet while doing this test to make up for removing the restriction of the air box.

If the throttle works OK, check the valve clearances. Its amazing how far out of whack those chinese valve stems can go.

By the way, it should have a bystarter attached to the top left of the carb - it looks just like the one on an SA50 if its a 4 stroke GY6.

[Wheelman-111]

Greetings:

Concur with Clive - diaphragm's likely bad. Add only that a patient approach is needed to reassemble. Time is on your side, as the diaphragm seems to get easier to handle as it dries/shrinks a bit. Double and triple-check that its edge "piping" is seated in the groove all the way around. Do not tighten screws until confirmed.

[odinxxix]

it is the MC-02-50B. and i was on 49ccsoot.com and they said the same check the diaphram. it seems to be sitting in the groove ok but that doesnt mean that there isnt a hole in it somewhere that i cant see even thru the light. it does have 2 holes in the bottom where the needle goes thru. ill see if i can watch the slide move gotts find my mirror.

[odinxxix]

do you think bad gas would cause this problem, they told me today the gas is about 8 months old.

[Wheelman-111]

Greetings:

Before I were a-smart from all duh edjama-cation here I had a hedge trimmer sit for 2 years between starts. Yes it did. I didn't know about Sta-bil then either.

8 months ain't that old. I doubt it's the gasoline. Sportsters in the South TX garage start with gas older than that.

You could test my VM24 by drawing on the outlet. The slide uh... Slid with a Bhang Breath. Suggest you drain the gas first. or at least stay away from matches for a while.

[odinxxix]

well i got it figured out. it turned out to be a broken air box. so i glued it and siliconed the crack and it took off. but at only 25 mph. so i told him to have the timing checked. on another forum it was found that sometimes they will come from the factory 10-20 degrees off. and that 1 out of 12 will run 45 mph they are the ones that have the inspection sticker from factory on them.

[Clivester]

The timing is pretty much fixed on these things - unless the cam chain was installed incorrectly. Much more likely to be a valve clearance issue.

[odinxxix]

what in the world are the reasons this stinking thing would spit out 2 brand new belts. and i mean shreaded looked like tangled hair.

[Wheelman-111]

Greetings:

If you got the belts on eBay for $7.99 including shipping, that's one possible reason.

Otherwise, an alignment problem or possibly a seized rear pulley. See if you can separate them by hand.

[odinxxix]

i will check to see if i can pull them apart. the belts came from a local shop for 26.99 each!!!