I rebuilt the carb on my 3hp lightwin and now it is running through a bowl of gas and then revving up really high and shutting off. What does this sound like, i have the top and bottom adjustments set as the local evinrude shop told me. Also the bulb goes soft after it quits as well, you have to re-pump up the bulb on the gas line. Any help is appreciated.
Hi Alan, The easiest test you can do is to unplug the line from the fuel pump to the carb at the carb nipple. Slide the line out over the side of the lower cowling into a coffee can. Prime the bulb until fuel comes out of the line. Now, pull the motor over and note whether or not any fuel is pumped out of the line. No fuel - no go. The fact that you have to pump the bulb to keep it running is a dead giveaway that you have a fuel pump problem....- Scott
It is running out of fuel. The revving up is caused by a lean mixture just before it runs out.I'm not aware that that engine had a seperate tank. If so, I would supect the fuel pump and/or connections.
We checked to see if fuel was getting to and from the fuel pump and it seems that it is. We were thinking that since it has a cork float it may be soaked and hanging down rather than floating with the fuel level. The fuel tank is not a part of the motor, it is a can that goes in the boat.
Update: I got a new fuel pump and it immediately fixed that problem. New issues however have arrived. At WOT it will only idle. It will stay running with no problem but it will not accelerate.. You can hear it pulsing a bit, like it wants to go faster but won't. We noticed that the bottom plug is fouling out almost immediately but the top plug looks good. We checked compression and it seemed low, about 32 psi per cylinder. Is that too low. We tookk of the carb and checked the float and the jets, all look good. Any suggestions. we adjusted the low speed knob and the lean/rich knob and nothing really happened at all.