Logo

2009 90hp optimax dies after start

Donniec2000

New member
Hello.
So, I'm seeking help for my boat motor.

2009 90hp optimax motor
serial 1b751611

Motor will start up, run a few seconds, then dies. Cycle key, hear the pump run a few second s, restart, instantly dies.

I have replaced the fuel line and bulb.
Drained fuel filter and VST tubes via the hose and bleeder (i think?) Screws on bottom sides that take allen wrench.
I've ordered a new filter but awaiting it's arrival.

Checking out the motor, the fuel shraeder valve on side of VST starts at 0 psi, turn the key and it quickly jumps to 30 then fades to 0. Does not hold pressure.

The 2 valves on the rail by injectors, when turning key, 1 (top)goes over 100psi (max on gauge) And one hits at around 90-95 psi.

As soon as fuel filter comes in, im replacing it.

Thinking i may have a bad fuel pump? Any suggestions which way to proceed? My local marine shop wants $400 for the pump on the bottom of VST and hasn't quoted price for the pump that stands up.

Thanks
 
Update.

New fuel filter came in today - OEM replacement, not a cheap one.

Popped it out and it was full of orange crystallized gunk. Cleaned out the part of VST it is in.

Took small square pump off the side, opened it up and same thing. Orange crystals everywhere. Cleaned it up and the brass valve and reassembled.

Fuel pump laying on its side in bottom of VST was very clean. No gunk or anything?

Fuel pump standing up had dmall amount of corrosion on gasket. The small rubber piece on top of fuel pump has a small split in it and appears misshapen.

Put everything back together the same way it came apart.

Replaced fuel line and primer bulb.

Checked for spark with some light tester. Got a steady red light across it. Not sure if it is supposed to be red.

Primed fuel, attempted to start, nothing. Motor just spins.

Tested fuel pressure at VST and getting nothing now.

Top valve on fuel rail only getting 30-40 psi.

Gonna get a rebuild kit for the small square pump on side and the rubber piece for the stand up pump.

Any other ideas? It's definitely a fuel delivery issue. Turn key on and a pump runs for around 3 seconds.

Sorry this is a book. Thank you.
 
Last edited:
Just posting an update. Maybe this will help someone.

I rebuilt the manual fuel pump on side of VST. Used the 2 longer screws upside down to build it back together lined up properly.

The fitting or coupler on the high pressure pump had a tear and was deformed. Replaced it at same time. Put everything back together and motor fired right up. Runs great again. Ordered the quicksilver parts from amazon. Was less than $50 and have motor back.
 
Back
Top