2012 YAM F90 Won't ReStart after normal run

[DSR-550SRMN]

I have (4) incidents of the where engine fires up & runs normal and won't restart after a run. Run the boat out 20-30 minutes varying speed up to full throttle. Get to destination turn off and won't restart. Wait roughly 10-15 minutes then re-starts normal and cycle repeats itself. After 1st incident replaced Racor fuel H2o separator filter, engine fuel filter and installed new NGK plugs. (Pulled plugs looked good) All connections checked for leaks & fuel tank vent & fuel bulb working normal. 2-4 events were all after driving 8 hours (400 miles) to new water destination. After 3 no starts engine to unreliable to continue trip. Returned home. Today inspected all wiring harnesses, canister and related fuel lines i.e. main fuel feed and hose lines to VST. Nothing abnormal. Drained fuel from VST. Under normal start & run engine performs great, no sputtering, hiccups, full power etc. all operating parameters (gauges & sensors) within normal. Acquired boat with 348.5 hours now with 355 hours. I can run the engine in my back yard connected to ear muffs/garden hose. Haven't started yet after VST tank drain because I need to recharge the fuel tank. Plan on doing this on Monday. ANY SUGGESTIONS????

[trevbouy]

This sounds fuel related. To restart engine it must have immediate fuel supply.

Sounds like yours is draining back on shutoff, is there a one way valve somewhere?

Could also be vapourlock from engine heat in one of the pipes, moved any lately?

[Limecc]

Onboard tank?
Why not borrow a portable 25l tank and priming line to do some diagnostics by process of elimination?

[charliee]

Stator or vapour lock - both caused by heat build, can be a bugger to isolate the issue.

[DSR-550SRMN]

Originally Posted by trevbouy

This sounds fuel related. To restart engine it must have immediate fuel supply.

Sounds like yours is draining back on shutoff, is there a one way valve somewhere?

Could also be vapourlock from engine heat in one of the pipes, moved any lately?

Recall 1st incident squeezed fuel bulb and didn’t help. Inspected “fuel strainer” above 1st fuel pump and actually looks like empty tube.

How to check for vapor lock? And/or heat in what pipes??

TIA

[DSR-550SRMN]

What is stator lock??

[DSR-550SRMN]

Originally Posted by charliee

Stator or vapour lock - both caused by heat build, can be a bugger to isolate the issue.

Yes I'm coming to the same conclusion its a bugger to isolate, thanks for the tip!!

[DSR-550SRMN]

Failed to mention that by a slight chance of luck I came across a marine engine tech that had a diagnostic unit while I was away at the dock that could read the engines on-board computer and it showed "no faults". Second, when I explained a no start after running some +/-30 minutes and won't restart the throttle position is in "neutral" and the key switch turned to start cranks the engine. It cranks over but doesn't fire.



If you have direct experience with this problem please by all means contribute.

[A1an]

When it is in one of its no start scenarios, blast a bit of brake clean or easy start in to the intake whilst cranking, if it fires you know it’s fuel related, if it doesn’t then you can look elsewhere.

[Bucksribster]

I had a similar problem on my Suzuki DF 140 a couple of years ago. Would start and run - not perfectly, but OK. Once stopped would not restart. Pulse were sparking and fuel getting through. I replaced lots of stuff, low and high pressure fuel pumps, IAC etc. In the end gave up and took it to the Suzuki guru ( Barry Windsor - Windsor Marine - top guy). He eventually traced it down to a faulty engine control unit. It was not turning off the fuel pump when the engine was stopped, and so was flooding the cylinders with fuel. The plugs were then too wet to fire. When it had time to evaporate ( like overnight) it fired again no problem. Apparently he diagnosed it by listening for the fuel pump when it was first turned off. Worked faultlessly ever since ( touch wood!).