View Full Version : 59 340 utility (gas) starts but only runs a few mins at at time

01-17-2010, 11:43 AM
59 340 utility (gas) starts but only runs a few mins at at time. has a marvel shot. carb, just had a rebuild kit installed. new points, condenser, plugs.wires etc. not understanding why wont stay running. please help!

01-17-2010, 12:48 PM
Vapor lock maybe?

01-17-2010, 03:22 PM
could be a plugged gas line at the tank or coil could overheat and die out. My 300U was 6v and some po converted to 12v battery with the same coil and NO resistor so point life was VERY short. Added a 12v to 6v adapter resistor I had around from the 60's and fixed.When it quits check to see if it still has spark?? if it does remove the drain plug in carb bottom and see if there is gas there. I hope you added a filter in line when you rebuilt the card.

01-17-2010, 03:23 PM
Vapor lock maybe?
NOT on a gravity feed system!

01-17-2010, 03:30 PM
Just a semi-educated guess. I've seen plenty of guys route their fuel lines too close to exhaust and wonder why the engine only runs when it's cold, then dies as soon as it starts to warm up (because the hot exhaust vaporizes the fuel in the lines before it gets to the carb).

09-08-2012, 01:47 AM
We have a 350 that did that, and it was something plugging the port at the gas tank outlet. Fuel would seep down over time, but when running, it would go a couple minutes, and the engine would starve for fuel and die. 5 minutes later, it would start right back up.