engine rebuild help!!

[05blasterkid]

I just got my top end done and it runs good but dies quick, its not getting gas through the carb. Me and my dad filled a spray bottle up with gas and took the back plastic off with the air cleaner and all and then sprayed gas into the back of the carb and it would run but only when the gas was being sprayed in. Any ideas of why it isn't getting gas through the carb?

 

[brandoz28]

sounds like an air leak. did you do a leakdown test?


and did you turn the fuel on?

 

[1995blaster]

^^^thats a good start
and dont spray raw gas in the carb of a 2 a stroke

 

[05blasterkid]

Fuel is on, leakdown test no

 

[brandoz28]

first clean out the carb, and make sure you're getting flow TO the carb. and check all gasket surfaces etc. there's a reason that the thing melted down the last time.

 

[05blasterkid]

OK I will let u know what happens tomorrow

 

[05blasterkid]

How would an air leak cause gas not to get into the carb? When I turn the gas on it flows from the tank through the hose and to the carb but the gas isn't going through quick enough to keep it running, would it be my main jet?

 

[05blasterkid]

And 95 I wasn't throwing raw gas in it was a premium (93) mixed 32:1 with yamalube 2r

 

[scotj77]

your pilot jet is what gives it gas at idel. try cleaning that out too. and you always want to do a leak down test on a rebubild. there is a diy on it show it to your dad he can find all the stuff you guys need in a hardware store. it will save a lot of money and work in the future.

 

[Kieran]

How would an air leak cause gas not to get into the carb?

if the gasket is not in good condition or not compressed by tightening, then you may get an air leak, and that makes it harder for the fuel to flow because the air which is mixed in with the fuel is leaking out and as a result the flow slows down and cant make it into the chamber in time.

 

[Sandking]

Try removing your gas cap. Sounds stupid but if your vent hose is clogged the gas won't flow. Common problem with those Shorty hoses.

 

[brandoz28]

i'm saying with an air leak, the motor is going to suck in more air than what it needs and make it appear as though its not getting fuel, but you neeed to make sure there's fuel in the bowl, check the float level, and make sure that the pilot isn't clogged

 

[Kieran]

i was sure it would lose the air and slow down the flow??

 

[brandoz28]

the engine is going to pull air in from everywhere it can, it may slow down the flow, but its also going to be drawing air from multiple locations, creating a lean condition.

 

[Kieran]

ahh makes sence

 

[xJust_Causex]

Just curious but did you rejet for all your mods, and how recent was the new top end gaskets. I'm guess you burned up your last piston so you rebuild it, well something nuked that piston, now you need to figure out what it was, otherwise you will nuke this one as well. I'm also gonna say that you have an airleak somewhere, it is very common to have some somewhere especially when you have the top end apart. Look up how to build a leakdown tester, or you can buy one from holeshotman, and do a proper leak down, so we don't have to see another "well I burned it up" thread.

 

[05blasterkid]

i just put the gaskets and the top end in yesterday and i siliconed all the gaskets down and they sealed tight

 

[Blaster200boy]

i just put the gaskets and the top end in yesterday and i siliconed all the gaskets down and they sealed tight

Whats your main jet size, pilot jet, a/f screw, and needle clip at? I run a 340 main, 3rd clip from top, 32.5 pilot, a/f screw 1.5 turns out. im running a little rich. Running Bel-Ray MC1

 

[05blasterkid]

im running a 310 main, stock pilot, 3rd clip. i Dont know if i was running lean or what i have been old i was running lean because my pipe was red hot when it blew, but i have alos been told that my oil injection could have quit. But i just wanted to get my blaster running good so i could do plug chops and find out, and i already unhooked the injector so im premixing 32:1 with 93 octane and yamalube 2r

 

[super noober]

im running a 310 main, stock pilot, 3rd clip. i Dont know if i was running lean or what i have been old i was running lean because my pipe was red hot when it blew, but i have alos been told that my oil injection could have quit. But i just wanted to get my blaster running good so i could do plug chops and find out, and i already unhooked the injector so im premixing 32:1 with 93 octane and yamalube 2r

did you block off all the hoses and the brass nipple on the carb where the oil injection used to go?