2006 60 HP EFI Stalls When Cold

So my 2006 Merc 60 EFI has been giving me issues lately. Whenever it’s first put in the water for the day it’ll often stall immediately when put into gear or after given throttle in gear. It will do this a couple times before returning to normal. Once it’s been running for a while it will run fine the rest of the day, starting and running fine even after a couple hours of fishing. It’s done this a couple times in years past, but this year it’s happening every time. Unfortunately, it did sit for about 7 months prior to this.

I’ve ordered a new low pressure filter, and I’m considering testing the fuel pressure at the VST and possibly opening it up. I’ve also considered the high pressure fuel filter or the temperature sensor.

Any more ideas before I start throwing more money at it?

It’s serial number 1B250285. I found what might be a small leak coming from between the low pressure pump and the head. Just a little bit of moisture on the head under the pump. Could this be the source of the issue?

Update: replaced the low pressure filter and found the filter to be pretty dirty and a good bit of old fuel crystals at the bottom of the bowl.

I also replaced the fuel line and primer bulb coming from the deck to the motor. Almost all of the inside wall is completely gone. My guess is a lot of it went into the motor.

Shining a light down the high pressure filter, the media looked pretty black. I’m guessing that’s more degraded fuel line. I’ll be testing the fuel pressure at the VST this weekend and adding injector cleaner to the fuel as well.

Update: new filters and fresh fuel with injector cleaner has not helped.

After really examining the motor I found a slight leak coming from the air intake. The motor is also slowly surging a couple hundred RPMs between 1500-2000 RPM. Any ideas?

When I see a cold running problem on an efi engine I think temp sensor first. If the poor thing thinks it's already warm the Fuel gets dialed back and instant hesitation or stall.

Clean or replace the IAC valve...

faztbullet said:

Clean or replace the IAC valve...

Click to expand...

Do you know if this model’s IAC is serviceable? Would you trust a used IAC?

Only use new....

Installed a new IAC and fresh plugs gapped to spec and now it runs even worse. Now it stalls just about every time coming out of gear and idles rough.

Plugs were gapped incorrectly. Idles fine now, but will stall at high RPM and when throttling down.

Resolved after plugs, both filters, new IAF, new temp sensor, and fresh gas with injector cleaner.