!!!help!!! Hammerhead gt 150 stalls at wot
 

Hello everyone, i have a question that seems to be stumping me...i recently got a 2008 hammerhead gt 150 with the gy6 motor..it had been setting up for 5 years and it was completely out of the weather...so here is what i done,
1. New petcock diaphram on gas tank.
2. New 26mm manifold intake
3. New 26mm carb with 125 main jet
4. New high flo air intake
5. New fuel lines, fuel filter, and vaccum lines
6. New orange hot ignition coil
7. New yellow cdi with adjustable curve
8. New variator sliders (11 grain)
9. New 1500 rpm main clutch spring
10. New clutch

so this thing busts right off and idles like a dream, and runs like a champ too, until you run it at wide open throttle for about 10-12 secconds or so..then it stalls out like my carb bowel ran out of gas...i can let off the gas and in about 4-7 secs its good to go again..i need some help fellers!!!!!! It runs to good from low end to right before it stalls out, so i'm thinking it a fuel problem..possible running out of gas, but i dont know how to get more gas to my carb???? Any ideas???

Hammerhead gt 150
 

Also, on the adjustable yellow cdi box, where do i need to have this thing set at??...it has a phillips screw on the cdi box and this is a dc fire cdi box for this unit..it did not come with any instructions for it, so i don't know where to adjust it at..

Get a clear fuel filter and see if it is running out of gas by looking at it when it acts up.

I had a similar problem that I never figured out. Eventually went with a Mikuni flat slide carb and it disappeared after doing the things listed below.

Get the clear fuel filter.

Try installing some larger diameter fuel hose

Make sure the float height is correct

Make sure the carb vent and hose is clear

Does the flat slide gravity feed carb work good on these buggies?? I do have a see through filter and I have the see through yellow fuel line too...so I will be trying this first thing in the morning...I sure appreciate it bud...I will gladly take any advise and ideas..

And carb vent line is clear too

You may need a bigger main

Main jet

Sounds like you ran it dry. Might need larger fuel supply as in bigger fuel lines.

I have tried switching out the main jet, I went up to a 130 and it was still doing it...bout to switch out the fuel lines with a lil larger ones...will post ASAP and give updates on this problem...I'm very curious though, has anyone tried the 30mm flat slide carbs on these buggies?? And how do they perform with them???

Ok fellers, I just got through changing out my fuel lines and went ahead and went with a larger size vaccum lines too...I went up to a 5/16 fuel line, I had to find a sure enough good hose clamp to hold this sucker on there, wanted to leak...but I got it all snugged up...even swapped out with a larger see through fuel filter...made a couple of test runs and still doing the same thing, stalled at 13 secs...I was able to tell I had no fuel in my filter when it stalled out on me...so that tells me I'm not getting enough fuel in my bowel...checked my float level and it is perfect...so, question now is, how in the world do I get more fuel in the bowel??????

Here's a potential suggestion just to experiment: run it with your gas cap loose and see what happens. Possible your vent for he fuel tank is not functioning. Fuel out has to let air in.

And also remember that your petcock itself may be your limitation. If your fuel lines are 5/16 but the petcock outlet is 3/16 then it doesnt really matter what size your fuel line is.

get rid of the vacuum style petcock I bet that's the problem, theres tons of people posting threads about not getting enough fuel and that vacuum style petcock isn't efficient.

Tomorrow I will be trying a gravity feed petcock and seeing if that will get rid of this problem..hopefully can do away with this vaccum style petcock all together...in my opinion, these things should not have ever been put on these buggies, I mean, why not put a gravity feed petcock to begin with...I sure appreciate all the help from everyone too..I will be posting updates soon as I have tried it out..

Still stalling with the gas cap loose too...it was a good idea though..thanks man

Those percocks are actually a fantastic thing on a stock machine. Keeps people from having to remember to turn the gas off and flooding out the machine. They just have their limitations if you bump the fuel requirements. Worse comes to worse go with a aftermarket tank with a larger fuel supply. I think they are called a spun aluminum fuel tank.

Make sure you don't have a vacuum leak. Under the intake is a plastic isolator, some use a o-ring on one side and gasket on other, some are gasket on both sides. The o-ring could be cracked or the isolator could be cracked causing a vacuum leak. The reason for the vacuum pump is for safety. Atv's come with petcocks, if rolled there is nothing keeping you on the vehicle. The buggy if rolled will build pressure in tank as it rolls and the check ball in cap will close off the vent causing fuel to still feed the carb in a roll over possibly causing gas to ignite on hot engine with occupant belted in. Not a good scenario.

I always thought not having too much Gas in your " BOWEL" was a Good Thing ? :fart:

Thanks so much guys...i took off my vaccum petcock and was going to run a gravity feed one, but before i did, i wanted to try something....so i removed the fine screen filter from the vaccum petcock and reinstalled it back on the gas tank, just to see if maybe the screen was slowing down the fuel..i have a really good inline filter already on, so, figured it was worth a try...to my surprise, i never stalled!!! Ran like a champ! Where before i was stalling around 13 secs or so, i was able to hold it at wot for 25 and never had a hickup....thanks so much for all the help, yall don't know how much i truely appreiate it..