Yamaha 90 sudden power loss then powers up again.

[Sea lyin’]

No nothing will show up unless there is a hard fault like an injector shorted. Etc.

Like I said these guys are right it very well could be a restriction. Or it could be an injector or even a plug. Sounds stupid, but I've seen it alot on the 4 strokes.

Change fuel filters everywhere
Remove anti syphon valve

See what happens

What other information will he be able to glean from a scan?

 

[ship happens]

What other information will he be able to glean from a scan?

Yamaha is not great for historical data. The diagnostics is meant to be used as a tool for diagnosing engine issues and testing.

The monitor screen shows active values from all related devices plugged in and the related volts, values or calculations based on the device type.

Then you have some ability to test devices such as injectors and electrical activated devices like pumps etc.

Aside from engine hours and active faults, yamaha is pretty limited

 

[Sea lyin’]

I spoke too soon when I said no alarms. When he first starts it from cold he get a single steady tone for about 3 seconds then it stops.

 

[sudsy]

I spoke too soon when I said no alarms. When he first starts it from cold he get a single steady tone for about 3 seconds then it stops.

I had a similar problem with a 2005 merc 115 (Yami head). It ended up being a throttle position sensor had a dead spot. When I went to throttle up it would stutter then continue gong up again. I bought a test lead plug for it and was able to diagnose it with a multi meter showing it drop in resistance as I manipulated the throttle.

 

[trophywife]

I spoke too soon when I said no alarms. When he first starts it from cold he get a single steady tone for about 3 seconds then it stops.

most likely just the start up warning

 

[ship happens]

Another thing, make sure the battery connections are tight with nuts cranked down . No wing nuts!

 

[Charts]

Had the same thing numerous times. Change your plug wires you aren't getting spark on a cylinder.. I bent mine in like 1/16 of an inch and that did it. Got the tip from breakers in Bamfield after thinking I'm heading back to port on my kicker