2016 F70 Issues

[Gatorlizard]

2016 F70 with less than 70 hours. New boat to me. Starts and runs like a champ for an hour and shuts down. Let it sit for an hour and it starts/runs fine for another hour and shuts down again. The boat is 21 years old so I replaced the fuel line, pickup, bulb and added a Racor filter/ water separator for good measure. Any ideas?

[99yam40]

you try running it with the fuel tank cap loose or off?
Just in case the vent is not working properly.

have you checked to see if spark is going away when it shuts down and will not start back up?

[Gatorlizard]

I got an inline spark tester and fuel pressure gauge. I'll try to see what tail to chase this weekend.

[F25Portable]

Running that long before shutdown, and then needing an hour of cooldown before running properly again screams ignition to me. Sounds like a coil breaking down. Coils seem to be way better than they were 20 years ago but if that isn't the textbook definition of an ignition break down then I don't know what is.

[Gatorlizard]

Running that long before shutdown, and then needing an hour of cooldown before running properly again screams ignition to me. Sounds like a coil breaking down. Coils seem to be way better than they were 20 years ago but if that isn't the textbook definition of an ignition break down then I don't know what is.

That engine has two coils on it. What are the chances of them failing simultaneously? I guess anything is possible.

[Tony Harper]

was RPM is it shutting down at ? low speed or high speed ? approx RPM when it shuts down may help diagnosis

[Gatorlizard]

was RPM is it shutting down at ? low speed or high speed ? approx RPM when it shuts down may help diagnosis

Both times it happened in the river it was at 18-2200 RPM. Same when running it in my driveway. It doesn't spit or sputter when it dies. It's like you switched it off. There is spark after it stops but the fuel pump doesn't make the normal buzzing sound. Just a single faint click when you cycle the ignition switch. After it cools down the furl pump buzzes and it fires up with just a bump of the key as if nothing ever happened.

[99yam40]

does pumping the primer bulb help any?
Might be the VST runs low on fuel where the electric pump has no fuel to pump?

if the VST is full all the time, then I would make sure there is 12 v + to the pump when the problem happens.
I guess the ECU grounds the neg to make the pump to run when the ECU thinks the motor is running, so need to find out what is supposed to make it realize the motor is running to make sure that signal is there

[Gatorlizard]

does pumping the primer bulb help any?
Might be the VST runs low on fuel where the electric pump has no fuel to pump?

if the VST is full all the time, then I would make sure there is 12 v + to the pump when the problem happens.
I guess the ECU grounds the neg to make the pump to run when the ECU thinks the motor is running, so need to find out what is supposed to make it realize the motor is running to make sure that signal is there

Pumping the bulb doesn't help at all. When I start the motor after it cools off it starts instantaneously without pumping the bulb. Something is failing after getting hot but I don't know what.

[99yam40]

as I said you need to see if the 12V + goes away or if the ecu drops the neg.
also what that ECU looks at to tell it the motor is running so it will keep the neg for the pump

[zenoahphobic]

Running that long before shutdown, and then needing an hour of cooldown before running properly again screams ignition to me. Sounds like a coil breaking down. Coils seem to be way better than they were 20 years ago but if that isn't the textbook definition of an ignition break down then I don't know what is.

Interesting you say that. Hope we get a final answer.

[Gatorlizard]

Electrical/Computer talk is way above my pay grade. I took it to the most respected shop in my area this week. I'll let you guys know what the outcome is.

[Skin diver]

Any updates to what was wrong?

[Gatorlizard]

Not yet. They told me 3-5 weeks. It's been 3 tomorrow. Some of the guys nearer to me that I don't trust told me 6-8 weeks. It is what it is.

[Gatorlizard]

It's been 8 weeks wed and I am getting tired of waiting. Probably going to bring it home this week and start swapping parts starting with the ECM. What the hell... It's only money!