Engine won't stay running - 1992 Evinrude 150hp TE150GLENC

[92 Nitro 190dc Owner]

I've rebuilt all 6 carburetors, installed new OEM Fuel Pumps, Fuel Pump pressure checks out at @ 2psi - 3psi. and holds it at that pressure, the vapor pump holds a vacuum, the vapor separator float is set correctly, the needle is not stuck (assume it's seating correctly). Fuel lines are not kinked or restricted and no cracks when flexed. The primer bulb pumps till it's firm and stays that way. Carburetor jets are clear. The engine starts right off, but will not run for long (a minute or two or less). I've run the engine from a separate tank with fresh fuel. I've used clear tubing for the fuel line to look for air bubbles. No air bubbles. My assumption is that the engine is not getting fuel, but don't know where else to look. The engine is a 1992 150hp Evinrude. It was originally a VRO set up, but changed it a couple of years back to two carburetors using premixed (50-1) fuel in the tank, because the VRO kept failing on me. Any thoughts on where to look next or what other tests I can run?

Background: Earlier this year, the outboard refused to start or run while out on the water. Discovered one carburetor was leaking quite a bit of fuel. Disassembled the carb and discovered that the gasket didn't quite align with one edge of the carb bowl. The gasket would not stay where it would provide the proper seal. I was finally able to keep the gasket aligned with the carb bowl by using gasket sealant that acted as an adhesive. Re-assembled the carb, pumped the primer bulb to build pressure and the leak stopped. However, fuel pressure in the fuel lines dropped very quickly. Of course, the outboard would still not start or run. I disassembled both aftermarket fuel pumps, but nothing stood out to indicate an issue. I decided to buy new OMC OEM fuel pumps to replace the aftermarket fuel pumps. I installed the new fuel pumps and the fuel system is now able to hold pressure. The outboard will start, but will only run for a brief time. I suspect the outboard is only running from the fuel in the carbs. Therefore, the engine is not pumping fuel to the cylinders. To me, this implies that the engine is not creating a sufficient vacuum to cause the fuel to flow to the carbs, since I've checked everything from the fuel tank all the way to the fuel entering the engine.

 

[92 Nitro 190dc Owner]

Could defective check valves cause the issue I'm experiencing?

 

[92 Nitro 190dc Owner]

Progress update: Engine is running purely by accident. I was checking the spark on left bank of the engine and all 3 appeared good. I was checking the spark on the right bank and the engine ran for a brief moment and then died. I wanted to check the spark without the engine starting for even a moment, so I disconnected the emergency/kill switch by pulling off the lanyard clip. I cranked the engine to examine the spark and the engine continued to run. I put the clip back on the the engine died. I repeated this process a couple of times, pulling the clip and trying to start the engine and putting the clip back on and trying to start the engine. The result was consistent (Clip on, the engine runs for only a second or two. Clip off, the engine runs without dying). The emergency switch is operating the opposite of what it is supposed to do. I will now test the emergency switch, the ignition switch, and all related wiring.

 

[Joe Winkler]

Progress update: Engine is running purely by accident. I was checking the spark on left bank of the engine and all 3 appeared good. I was checking the spark on the right bank and the engine ran for a brief moment and then died. I wanted to check the spark without the engine starting for even a moment, so I disconnected the emergency/kill switch by pulling off the lanyard clip. I cranked the engine to examine the spark and the engine continued to run. I put the clip back on the the engine died. I repeated this process a couple of times, pulling the clip and trying to start the engine and putting the clip back on and trying to start the engine. The result was consistent (Clip on, the engine runs for only a second or two. Clip off, the engine runs without dying). The emergency switch is operating the opposite of what it is supposed to do. I will now test the emergency switch, the ignition switch, and all related wiring.

I actually tore a switch apart to see the failure one time, and the switch was full of white corrosion and causing the little flipper contacts to bend.

 

[Thomas Teller]

Replace the ignition switch, Evinrudes have a terrible track record for failures, only get an OEM to avoid issues

 

[92 Nitro 190dc Owner]

Agreed with having an OEM switch. In my case, the ignition switch is OEM and about two years old. I'm checking that in addition to the emergency kill switch to verify that there is no issue with the switch itself or it's wiring (loose wire, disconnected wire, etc.).