6 months of sitting. Starts good. Dies when touching gas.
 

Less than a year ago I purchased a crank no start 150cc fox carbide. Did a 155cc big bore kit with cam and uni intake along with perf coil new plug and gutted exhaust. Big jets in the carb as well. After all that started and ran great. Rich at idle perfect up to wot @ 40mph

Let sit for 6 months. Charged battery today and cranked for a few mins. Finally started. Right away I noticed it would die as soon as throttle is cracked. Let idle a little more to warm up a bit. Starts everytime first crank but dies right away when cracking throttle even a hair. Played with air fuel screw but no change.

Any help would be greatly appreciated. Can't wait to get it running and back it out of the trailer at the new house.

time to clean the carb most likely. can't let ethanol mix fuel sit in these things for more than a couple weeks. If not that, they maybe check your valve settings

Also, maybe your fuel enrichment valve went bad.( or auto choke as some call it)

Wow. Couple weeks????

Ethanol mix your talking about reg pump gas right?

What about the vac actuated needle that comes down through the main jet from top of carb. What if that is stuck in the jet. Could that give me a similar prob?

I am not really sure, just throwing that suggestion out there. Mine went bad so I just ordered a new one. I hope it fits.... And works.

I'm doubting its the valves. When putting the motor back together I adjusted to .004-.005 and after a few miles I rechecked and they were the same.

Auto choke. You mean black thing with 2 wires??

Trying to understand the carb a little better. At idle the vac from engine is pulling fuel through the idle jet right? Then after idle vac needle in main jet raises and lowers to allow more or less fuel through main jet right? Is this correct?

Went out and checked again. Starts and idles perfect but the slightest opening of throttle turning cam on carb with my hand kills engine right away.

Sounds like an air fuel problem play with the screw. Sounds like that is the problem. Do you still have the stock a\f jet #35?

When I read your earlier threads it said you ordered a 40 a/f jet?
Try the stock one first. Seeing hiw that jet affects the beginning to 1/2 throttle.

Idle jet is 1 up so if stock is 35 then I think I have a 40

My main is somewhere around a 135

I like the jets I have. When it was running 6 months ago it was running perfect. Nice burn little rich. Good response. Messing with screw does nothing.

Something has happened from sitting. How does the long main jet needle work? I know it operates off the diaphragm up top. But can that needle stick?

Thinking if that is what controls fuel intake after idle and it's stuck then when opening throttle more fuel should come through from needle riding up and if that needle is stuck then it would die because of lack of fuel.

correct, pump gas ... it bites ... my wife doesn't ride her baja much. If i don't shut the fuel off, run it till it's out of fuel then drain the bowl, I get EXACTLY what you're getting. I have 4 carbs. every time i forget to run it dry and it sits a month or so, i hit the same problem and just swap to a clean carb and put the one off it in the "to be cleaned" line ...

You are on the right track now. I think you need to pull the carb and fuel tank and thoroughly clean out both. It sounds like the enrichment valve is the only thing keeping the engine running at idle. The pilot jet holes are very small, even with a bigger one installed.

I go into great detail, as I'm sure X can too, about the negative effects of ethanol in our pump gas. The ethanol is alcohol, alcohol is water based, moisture brings corrosion, corrosion clogs things. If you let it sit up, next time drain the bowl and let it run out of gas and shut off, or run ethanol free fuel. I purposely run ethanol free in all my small engine stuff for this reason, or you will need to rebuild the carb about once a year. I let my mower sit for around 4 months, primed it and it fired off first pull.

clean carb

/thread

do not let your buggy just sit

if you are going to do that you need to add fuel stabilizer

i also recommend when you are going to put it up for any period to let it idle and then close the stopcock and run the carb dry

restart it maybe twice after it shuts off to make sure you got most of it

You have a lean condition. Most likely a clogged pilot jet. Also could be an air leak. Spray some starting fluid around your intake manifold while it is running and listen for rpm change. Or check for unplugged or cracked vacuum lines.

Oh wow so the E valve can let enough fuel in to run? In that case im sure both jets are clogged and i need to clean them.


Ok so you think ethanol gas sitting for 6 months will def clog jets huh?

Ill pull top of carb off cause its simple and make sure needle is not stuck. Also check vac lines etc.

Masteryota just wrapped up building a 3.4 for my mkiv supra. Lookin to run 8s this season.

1/8th or 1/4?

1/4


Gonna head out shortly and pull carb.

On your mods mentioned the pilot should be no larger then 138 and main maybe a 128 at most. Too rich mixture will eventually wash out your rings. Go online to pure-gas.org and look for stations in your area that have non ethanol fuel. The ethanol will kill a carb and engine. Stabilizers will not work with ethanol, don't care what they claim. Been there done that. The only fuel to use is non ethanol.

Sweet, must be a small package monster--sorry but cars always pull me off topic. post some pics!

Yeah its gonna be a monster.

Sycarms i know my idle jet is one step up. My main is a 135 i think. Like i said was running perfect when it was running.

Ill post some pics X

Niiice ...you gonna have to take a sawzall to the hood? :biggthumpup:

Wasn't meaning to call you out/put down by asking, but i hear the bs bingo all too often about running times then find out they've never been down a quarter.

Back on topic, prime example of your problem ... just finished piecing together a gy6, got it to idle with a "dirty" carb, (had been working fine til it sat) touch the throttle and it died. pulled the "clean" carb off my wife's baja a couple minutes ago, and presto, full revs.

BTW, thanks Tom! the thing sounds really strong--now i'm thinking sell the SYM!

That motor need to go into your buggy.:banana::lmao:

lol the torque would wrap the frame around the engine

X I'm with ya on the bs. Last season stock 3.0 with an 80 mm snail put me in the 9s a few times @ 9xx whp then bottom end let go. This 3/4 cemented 3.4 with a new 4788 and supporting mods should put me in the 8s. As for the hood it should clear. Did some custom manifold spacing so stock hood should clear.

Got wrapped up in fam things today but gave the buggy some spray when running and it revved up so I'm gonna have to agree with you all and say jets are probably clogged. Hopefully it's up to 40 mph tom

Allright finally got around to pulling the carb. All ports and jets clean as a whistle. Again starts immediately but rpms will not increase no matter what. When starting it idles a little higher like it should then drops down after a minute a bit to a correct good idle. At any point when cracking throttle it dies. I'm lost at this point.

Just for ****s and giggles, have tried the 35 stock pilot yet?

Allright everyone hope this helps cause I'm sure people will run into this in the future. Charged battery and voila!!!

Always the simple stuff but FYI after 6 months of sitting with pump gas my carb was clean as can be.

Reason this thing didnt start and run right away in first place is cause my stupid *** had the kill switch pushed in which i cranked a bunch and drained battery. Then after pushing kills witch to run position battery had just enough juice to start but not rev above idle.

Putting it back together and taking it out today.

And for the record I do have a bbk with cam also perf coil. Uni intake and gutted exhaust. Have 40 pilot and 138 main. Starts revs and runs great. I would rec for my mods a tad less on each jet. 38 pilot and 135 main would be perfect.

:stupid::buttkick::banghead:

haha glad it is working.

I should be reassembling mine tomorrow hopefully. Gaskets and high performance coil should be in.
The biggest main jet i have is a 134 I am at 700' elevation I hope it will be big enough. I am getting anxious to hear how BBK sounds and feels.

Been there done that:banghead: More then once too:banghead::banghead:

Glad to hear problem solved. I've got an old TBI dodge dump truck at work that the battery hangs me out like that. can't get the boss to pony up for a proper group size battery for it. Electrco hydraulic dump, run it and it kills it if i don't keep it revved. go to low on the juice and the truck will fire but not run.