Yamaha 2006 T50TLR stalls after 40 minutes running and wont start

[Outboard Mike]

Have a 2006 Yamaha T50TLR 4 stroke with EFI that will run for up to 40 minutes and then stall out and not start. If you let the engine sit for a while it will start back up after it cools down. We have replaced the low pressure fuel pump and replaced the fuel lines but still have the same results. The next step is to replace the high pressure fuel pump. I know there was a fuel restriction issue with some Honda 50hp 4 strokes that involved a grommet on the high pressure fuel pump expanding or bloating after running for 20 minutes or so and blocking off the flow of fuel to the engine and causing a stall condition. The configuration is almost the same on these motors as the Honda but the part is called a pump damper on the Yamaha. Has this been identified as an issue on Yamaha 4 stroke EFI models. I hate to spend over $300 on a high pressure fuel pump if the damper or grommet is the issue. Best time of the year to be on the water and hoping to get boat running right.. . .

 

[Sea Rider]

If the motor stalls when running, let cool, run again with no issues to stall again, definitely it's not a mechanical thing that heats up and misses, seems more of an electrical issue, heats, misses, cools , heats, misses and so on. It's a 14 year oldie and any electrical component could have gone bad through the boating years.

Happy Boating

 

[Outboard Mike]

What electrical components should I be looking at?? Is there a troubleshooting guide for electrical issues for this motor? Not sure what components I would be able to test. Just hoping to get it on the water during the best time of the season. Thanks for your help and direction.

 

[Sea Rider]

What electrical components should I be looking at?? Is there a troubleshooting guide for electrical issues for this motor? Not sure what components I would be able to test. Just hoping to get it on the water during the best time of the season. Thanks for your help and direction.

Will need to get a Yam Service Manual for that motor, there should be stated all the electrical parts and how to troubleshoot them correctly including their individual Ohm readings and DVA voltage output for each electrical component. If have already checked all the mechanical and fuel related parts with no avail, next is an electrical troubleshooting...

Happy Boating

 

[Outboard Mike]

Update: I replaced the spark plugs, gas line from tank, primer bulb, gas line fitting, and fuel filter. The fuel filter was the original and was definitely in need of replacing. There was some debris in the bottom of the fuel filter bowl that I cleaned out. I added 6 gallons of recreation fuel and she ran great for an hour and a half and is running great ever since. Sure glad it wasn't the high pressure pump or electrical. Life is good