F300 random shut off

[RodWorks]

2015 F300 4.2 liter with DET dual station controls. Having an issue with engine shutting off, tends to happen above 4000 rpm or during acceleration. Gauges stay on, no alarms, checked and tightened all battery and engine terminals. Replaced battery twice, new battery switch, new positive and negative terminal posts.

When it stalls, you can move throttle to neutral and engine cranks right back up. Runs perfect otherwise and recently serviced.

Any ideas on where to troubleshoot before bringing to a Yamaha tech?

[99yam40]

loss of fuel pressure will turn a motor off like you turned off the switch.
you need to find out if you have a fuel problem or not
and then chase spark
or see if you have spark when this happens and then chase fuel

[RodWorks]

Thanks, spoke to a tech today and he seemed to think it was fuel related. We'll see thanks for the advice.

[Mytoolguy]

2015 F300 4.2 liter with DET dual station controls. Having an issue with engine shutting off, tends to happen above 4000 rpm or during acceleration. Gauges stay on, no alarms, checked and tightened all battery and engine terminals. Replaced battery twice, new battery switch, new positive and negative terminal posts.

When it stalls, you can move throttle to neutral and engine cranks right back up. Runs perfect otherwise and recently serviced.

Any ideas on where to troubleshoot before bringing to a Yamaha tech?

Mine did the same was low pressure pump. I opted to get an aftermarket for $80 and cleaned out everything and swapped out both filters, No problems up until today with no crank but I think that's a communication issue with my binnacle

[RodWorks]

Replaced VST filters and high pressure fuel pump and still have the issue. Tech was unable to duplicate the issue while on the computer.

I’m going to disconnect kill switches and test tomorrow. Also, going to disconnect water pressure and speed sensors and test. Lastly, running a main harness over the deck to test.

[RodWorks]

Mine did the same was low pressure pump. I opted to get an aftermarket for $80 and cleaned out everything and swapped out both filters, No problems up until today with no crank but I think that's a communication issue with my binnacle

When the issue happens the primer bulb only needs one pump to be firm. Tech said this rules out the low pressure fuel pump.

[Mytoolguy]

When the issue happens the primer bulb only needs one pump to be firm. Tech said this rules out the low pressure fuel pump.

Ok so throw an after market LP pump in and see what happens. At higher RPM's the LP pump can't fill the VST fast enough.

[RodWorks]

Ok so throw an after market LP pump in and see what happens. At higher RPM's the LP pump can't fill the VST fast enough.

Ok, I'll see if they have a spare to test.

[RodWorks]

Bypassed kill switches, and entire 2nd station controls. Disconnected water pressure and speed sensors. Ran separate harness over the deck. No luck....

Read something about CAM sensors causing an issue like this, but I don't have the engine code?

Also, I've found the issue consistently happens after running fairly hard for 30 minutes and then turning off for 15 minutes. Cranks right up and idles fine, but when you go hard to get on plane it dies. Starts immediately after the stall and will run fine under 4000rpm. After running easy for a few minutes you can run hard again without issue.

[Mytoolguy]

Bypassed kill switches, and entire 2nd station controls. Disconnected water pressure and speed sensors. Ran separate harness over the deck. No luck....

Read something about CAM sensors causing an issue like this, but I don't have the engine code?

Also, I've found the issue consistently happens after running fairly hard for 30 minutes and then turning off for 15 minutes. Cranks right up and idles fine, but when you go hard to get on plane it dies. Starts immediately after the stall and will run fine under 4000rpm. After running easy for a few minutes you can run hard again without issue.

almost exact same scenario as mine until I switched out the LP fuel pump. Haven't had the issue since. You can get them on amazon for under $100. It's just a fuel pump and the LP is fairly easy to swap out.

[RodWorks]

almost exact same scenario as mine until I switched out the LP fuel pump. Haven't had the issue since. You can get them on amazon for under $100. It's just a fuel pump and the LP is fairly easy to swap out.

Wouldn't the VST have to be empty to cause a stall with a LP pump failure? Why would it only take one squeeze of the bulb to get firm?

Honestly, I'm going to swap it out, just to rule it out. Thanks

[99yam40]

Wouldn't the VST have to be empty to cause a stall with a LP pump failure? Why would it only take one squeeze of the bulb to get firm?

Honestly, I'm going to swap it out, just to rule it out. Thanks

I agree, the VST would have to be empty to cause the stall if the LP pump was the problem.

maybe Toolguy can explain how that could be wrong

[Mytoolguy]

I agree, the VST would have to be empty to cause the stall if the LP pump was the problem.

maybe Toolguy can explain how that could be wrong

Because I had the exact same symptoms. At idle or lower rpm no issues. Anything over 3400 rpm for me the engine would die intermittently but start right back up.
With power to the LP pump it still kept the ball relatively hard and able to keep up with the fuel demand at lower RPM's. So at higher RPM's the VST is probably getting empty and as soon as your ready to crank the engine back over there is enough fuel in the vst to do so.

Not saying the LP pump is completely shot but most likely on it's way out.

[Mytoolguy]

try a LP pump any updates?

[RodWorks]

No, the tech said he was gonna do some research and call Yamaha for some advise. I was giving him some time. Thanks for checking.

The frustrating thing was he ran it on 3 different occasions and couldn't replicate the issue with the computer hooked up.