2016 F70 Issues

[Gatorlizard]

I used the Star Brite descaling flush.

[99yam40]

that foam was from the mineral deposits lining the surfaces being dissolved.
what did you use to do this?

[Gatorlizard]

I did the acid flush as directed. I can't say it really did anything as all I noticed coming out of the exhaust hub was foam. No particulate matter. I did remove the thermostat and replace the anode after flushing. The motor is running well after cleaning the fuel cooler. A 40, 50 and 60 mile round trip with no issues. Knock on wood!

[99yam40]

It's really no more than an acid solution you gravity feed through the flush muff with the engine running until it runs out of the prop hub. Let it soak 5-10 minutes and do it again. I cannot see where it would hurt anything if I flush everting out after using it. Considering the back story on the engine I'll probably do it. I'll probably take the thermostat out before doing it.

most recommend removing the internal anode while using it or replacing with new after.
I have read good report on the Rdlyme descaler, but it is used with a pump and run for hours to clean things up

[Gatorlizard]

I am not familiar with those kits, so I have no idea how well they work

It's really no more than an acid solution you gravity feed through the flush muff with the engine running until it runs out of the prop hub. Let it soak 5-10 minutes and do it again. I cannot see where it would hurt anything if I flush everting out after using it. Considering the back story on the engine I'll probably do it. I'll probably take the thermostat out before doing it.

[99yam40]

What do you think about those acid flush kits like Starbrite sells?

I am not familiar with those kits, so I have no idea how well they work

[Gatorlizard]

if there was a build up inside the cooler that caused overheating of the fuel in the VST, that cleaning out should have taken care of it.
something to think about, if the motor has crud that can get into that cooler line, it may repeat

What do you think about those acid flush kits like Starbrite sells?

[99yam40]

if there was a build up inside the cooler that caused overheating of the fuel in the VST, that cleaning out should have taken care of it.
something to think about, if the motor has crud that can get into that cooler line, it may repeat

[Gatorlizard]

I think I finally solved the problem. Knock on wood! I rethought the circumstances under which it shut off. I ran the boat again at speed but gradually reduced the RPM over the last mile before running at low speed. It wouldn't shut down as long as I did this. If I ran it hard and pulled the throttle back it would shut off after 5 minutes at low rpm. The last time the shop had it they said the fuel cooler was the issue but they didn't take it off. Al they did was blow air back and forth through the hoses under the manifold. I took the cooler off and flushed/soaked it a half dozen times with acid until I got clean acid out. Put everything back together and ran it 12 miles round trip at 4000 rpm. Pulled it back to 2000 rpm for the last mile to the ramp. It didn't shut down. What do you think?

[Gatorlizard]

Fail on the river today!! Ran for 45 minutes at varying RPM. As usual it quits at 18-2200 revs. Took the cowling off and 20 minutes later I pumped the bulb up and went back to the ramp with it off at 1800 rpm without a problem. I have got to find someone who knows his way around these engines. I don't care if he is 200 miles away from me.

[99yam40]

Thanks for the update, and I hope it runs well out on the water

[Gatorlizard]

seems you left out what they did to the motor.
info like that is interesting to all of us

Guess I did leave out something... Fuel cooler/hose clogged causing vapor lock within the VST.

[99yam40]

Got it back Tuesday but didn't get a chance to run it until today. It ran for an hour and 45 minutes on the hose at 2200 rpm without shutting down. That longer than ever before since having the issue. Won't get it to the river before Saturday.

seems you left out what they did to the motor.
info like that is interesting to all of us

[Gatorlizard]

Got it back Tuesday but didn't get a chance to run it until today. It ran for an hour and 45 minutes on the hose at 2200 rpm without shutting down. That longer than ever before since having the issue. Won't get it to the river before Saturday.

[Double_A]

SOLVED. I spoke to my mechanic and told him what I was seeing. He asked if I had a water pressure sensor, which I do. He said the water pressure and the oil pressure sensors were notorious for leaking into the connector on the older motors like mine. I went out to the garage and unplugged the water pressure and looked at the connector, it had a tiny bit of corrosion in it. With the ignition on, the computer showed stable TPS voltage. I let it stay on for 10-15 min, no problems. I took the boat outside ran it on the hose for 15 minutes ran perfect no errors. Went to the neighborhood park with a long fresh water canal and ran it 10 miles no problems ran like a clock.

Long story short my mechanic did me a solid. I always thought the engine got hot and caused an error (vapor lock or got some component hot), but what was really happening water got into the harness and shorted it then it would dry out and run normally. It was hard to diagnose since every time I took it to the shop it ran fine. I feel confident the problem was solved since it wouldn't run for more than a few minutes at a time recently ( this morning). I have chased this problem for years I hope this post might help someone else out. If this ends up being a false positive I will post here and let you know.