Not getting fuel to the cylinders?

[hyperlite33]

If the 'shee has been sitting for a while, it wont start and no matter how many times you kick it, the plugs are still dry as a bone. I can take off the filter, and jam a rag in the air box, to cut off air supply, and it starts right up. Once started, it runs flawlessly and idles perfectly.

Could this be a ploblem with the reeds not letting gas in, or a normal problem? I have gone throught the carbs and they seem to be okay, its has good spark and compression. :shrug:

Any ideas would be much appreciated!! :thumbsup:

[Dinner]

I'm guessing you have tried pulling the choke all the way out and trying to start it with the choke on. Have you checked your pilot jet, adjusted your air/fuel screw? You might need a bigger pilot.

[hyperlite33]

I'm guessing you have tried pulling the choke all the way out and trying to start it with the choke on. Have you checked your pilot jet, adjusted your air/fuel screw? You might need a bigger pilot.

 

Yeah I've tried the choke...It doesn't seem to help at all. I am new to working on carbs, but wouldn't a bigger pilot cause it to idle bad? If not, what does the pilot jet do?

[Dinner]

A larger pilot would cause it to idle bad, if your jetting was off. The pilot helps with idling, to 1/4 throttle. If adjusting the mixture screw won't improve the low-end running speed it's time for a different pilot jet.

 

This should help:

Jetting

Edited October 22, 2006 by Dinner

[fox_forma]

just the statement saying you pulled thr airfilter and jammed a rage in there to get it to fire up is a good indicator that you are lean on the pilot circuit and it needs to be richened up. When was the last time you did a rebuild? If it was slowly getting worse and worse that could be the culprit

[hyperlite33]

just the statement saying you pulled thr airfilter and jammed a rage in there to get it to fire up is a good indicator that you are lean on the pilot circuit and it needs to be richened up. When was the last time you did a rebuild? If it was slowly getting worse and worse that could be the culprit

 

Thanks guys for all your help! I got a compression tester and I am going to check the compression before I dig into the carbs. It does bog down quite a bit off the start which make me think it is the pilot jet. Once it is run for a while though it runs fine and idles perfect no matter if it is warm or not.

Does anybody know what a stock engine's compression should be at 5300 ft?

Thanks!

[hyperlite33]

Okay...I just did a compression test, and came up with 89 psi on the left and 92 psi on the right. Does this sound low even though I am at 5400-5500 feet here? This is also not warming the engine up. I am pretty sure the engine is all stock, but not sure as I just got her a couple weeks ago.

Edited October 24, 2006 by hyperlite33

[dajogejr]

Actually...that's about right for being that high up.

Stock near sea level is 130, give or take.

You should pick up a cool head with 19cc domes or cut .030 off the stock head to gain some lost performance from that high of an altitude...

 

It would be a great idea to completely clean out the carbs, especially since it's been sitting a while...but, try turning the air screws all the way till their lightly seated. Count how many turns on each.

 

I would also ditch the gas and get fresh gas and two fresh spark plugs, too.

 

Then, back each one out 1/2 turn...see if that gets any better....

 

Here's a chart from Dave Noss, who makes the Noss Cool head. It's an estimate, but...as said, you're not too far off.

 

Sea Level 1000' 2000' 3000' 4000' 5000'

18cc 197 178 171 170 165 145

19cc 183 167 160 158 152 137

20cc 169 156 149 146 140 129

21cc 156 145 138 134 128 121

stock 130 125 118 112 106 100

[sheefreak]

You can do the same thing by closing your airscrews up as stuffing a rag in the end of the carb. You might suck in whatever is foreign on the rag not to mention pieces of the rag. Sounds to me like you may have an airleak. If you are indeed all stock and your air screws aren't wide open I would look in that direction.

[hyperlite33]

Actually...that's about right for being that high up.

Stock near sea level is 130, give or take.

You should pick up a cool head with 19cc domes or cut .030 off the stock head to gain some lost performance from that high of an altitude...

 

It would be a great idea to completely clean out the carbs, especially since it's been sitting a while...but, try turning the air screws all the way till their lightly seated. Count how many turns on each.

 

I would also ditch the gas and get fresh gas and two fresh spark plugs, too.

 

Then, back each one out 1/2 turn...see if that gets any better....

 

Here's a chart from Dave Noss, who makes the Noss Cool head. It's an estimate, but...as said, you're not too far off.

 

Sea Level 1000' 2000' 3000' 4000' 5000'

18cc 197 178 171 170 165 145

19cc 183 167 160 158 152 137

20cc 169 156 149 146 140 129

21cc 156 145 138 134 128 121

stock 130 125 118 112 106 100

 

 

That was just the chart I have been looking for!!! Thank you very much!! I have gotten new gas with 93 octane and am mixing at 50:1 with Amsoil Dominator. New spark plugs didn't change anything, but I am now suspecting the pilot circuit due to the above chart like everyone has said previously.

Now another dumb question...Is the air/fuel screws on a stock carb right in front of the air box hose? Clockwise is richer and counterclockwise is leaner?

Thanks for all your help everyone...I am enjoying learning this stuff rather than paying someone to do it for me!! This site is awesome!

[sheefreak]

Yes, turning to the right(closing them, inturn choking off your airflow, inturn making it richer) Another thing you might check is your float bowls. If they have been taken apart they may be on the wrong carb, which will make the choke work improperly. This may explain why you have a hard time starting it, but runs great once she is warmed up. The bowls look identical, but they are not. Mine were labeled 1-1 and 1-2 in the inside bottom of the bowls. 1-1 goes on the carb w/the choke pull.

[hyperlite33]

Yes, turning to the right(closing them, inturn choking off your airflow, inturn making it richer) Another thing you might check is your float bowls. If they have been taken apart they may be on the wrong carb, which will make the choke work improperly. This may explain why you have a hard time starting it, but runs great once she is warmed up. The bowls look identical, but they are not. Mine were labeled 1-1 and 1-2 in the inside bottom of the bowls. 1-1 goes on the carb w/the choke pull.

 

Good call on the float bowls...I'll check that tonight! Is there a measurment in the bowls since I have them apart to have the floats set at?

[dajogejr]

You want the actual spec or the "eyeball" spec...lol.

 

Turn the carbs upside down, the bottom (top edge) of the float bowl should be level.

 

However, from the gasket surface on the carb (no gasket) to the float should be 21mm.

Remember, the needle has a small spring on it (to help it from bouncing going over bumps, etc.) make sure you're not depressing the spring in the needle when you set it.