Mind_Reader7

Ok guys, I've come here before with my problems on trying to fix this car up (bought it second hand). Anyway, I've got the car together now, and the engine won't work. I can get the engine to kind of start, the best I got was idle, then the second I put a tiny bit of throttle on it, it died. Can someone give me a rough idea where to start? It's a brand new carburator. I assume there's something more to it then it being to rich/too thin.

thomasgoalie2

are you sure the fuel is getting to it or the fuel line is blocked

got_nitro

iTrader: (24)

(NEW CARB)
If it's snuffin out from idle to when you give it some throttle, thats a rich LSN but.........
Make the idle gap 1 credit card in width by adjusting the idle screw, HSN 3-1/2 to 4 out, LSN should be flush with the throttle horn or about 1-1/2 out.

You can do a pinch test as a guide too. Pinch the fuel line about 2-3 inches away from the carb nipple while it's running. If it dies out in about 3 seconds, your LSN is fine, if it dies before that it's lean,beyond 3 seconds it's too rich. Adjust your LSN in incriments equal to 5 min on a clock.

Mind_Reader7

That's a good test.

Storydude1

iTrader: (7)

Also good for figuring out if your LSN is too rich or lean.

Too rich, it'll gain RPM before it dies. Lean or decent tune, it'll die out with no RPM increase.

jwm2

iTrader: (5)

If it doesn't rise at all when pinched then you are running too lean. It should build up rpms for a second or 2 and then die out. Check the tuning bible at the top of this section. It should not build up rpms to the point of engaging the clutch though, that is when its too rich. It should take about 4-5 seconds for the engine to quit running, the first 2-3 seconds it won't do anything the last 2 seconds it should build rpms and then die. But the lsn should only be changed after the hsn is tuned as the hsn controls the overall fuel flow and will affect the lsn when changed.

jwm2

iTrader: (5)

If its a new carb on an old engine then thats why. The carbs are set for break-in and not day to day running. You'll need to adjust the hsn a 1/4-1/2 turn or so in and start from there. Once you get the hsn set then move onto the lsn. Also check the pinch on the engine, if the piston moves freely up and down the sleeve then chances are it needs to be repinched.

So first thing i'd do is check the pinch, rotate the flywheel and make sure it gets harder to move the flywheel at the top, if not then you'll chase a tune all day long and eventually get frustrated and put the truck away on a shelf.

jwm2

iTrader: (5)

From my experience with a brand new trx 3.3 i had a few months ago the lsn was very rich as well. So it won't hurt to turn that in a tad as well about a 1/4 turn. Then start it up and see where it is tunewise after its heated up for about a full tank of fuel. Keep an infared temp guage handy just in case. The engine shouldn't get much past 260-270 and certainly should not touch the 300s. If you see it getting up over 280 then shut it off and report back for further instructions