2007 Mercury 90ELPT 4S cuts off shifting into Neutral

[Csupp11]

I need help with this one! Engine cuts off when I shift from “in gear” to neutral. It happens every time. It doesn’t seem to make a difference whether I’m shifting from forward or reverse into neutral. Obviously, this is a problem when trying to dock or put on the trailer. It will restart in neutral & idles fine. It doesn’t cut off when I shift from neutral into gear (F/R). Otherwise, it runs fine at any speed. I would think the idle is too low, if it cut off when shifting from neutral into gear, but my problem is just the opposite! Any thoughts or suggestions? Thank you in advance!!!

 

[saltchuckmatt]

Only thing I can think of is the nutruel locator switch in the control box is malfunctioning.

 

[QBhoy]

Either the shift switch or tps (known for it) or the IAC perhaps. Former would be the favourite odds on, if it were me.

 

[Scott Danforth]

Check the shift interupt switch

 

[Csupp11]

Check the shift interupt switch

Is that the plunger type switch that is activated by the shifter cables cam/lever in the bottom of the upper cowling? I was told to check the neutral safety switch under the motor. Is that the same thing?

 

[racerone]

Neutral safety switch prevents starter motor from operating if motor is in gear.----Nuetral switch tells ECU that motor is in neutral and prevents motor from running at high RPM in neutral.----Step #1 is to see if you have spark on all plug leads.-----And use a timing light to see what happens to sparks when you shifty to neutral.

 

[Csupp11]

Neutral safety switch prevents starter motor from operating if motor is in gear.----Nuetral switch tells ECU that motor is in neutral and prevents motor from running at high RPM in neutral.----Step #1 is to see if you have spark on all plug leads.-----And use a timing light to see what happens to sparks when you shifty to neutral.

Local dealer had it for a week, before I noticed this issue. They checked compression, spark plugs, & injectors, all good! I’ve had this out on the lake a few times in the last month. It’s a 2007 Mercury 90hp EFI 4 stroke. I ran it at least 2 hours each time. Runs perfectly up to 6k rpm, & steady cruising at 3200 rpm. The only problem is when docking. Idle thru no wake zone is good, but when I shift from fwd into neutral, engine stalls every time. It will start right up & shift into rev & keeps running. Then shifting from rev into neutral, it stalls again. Idle is smooth in neutral & while in gear, around 700-800rpm. The problem I’m trying to solve is why it stalls when shifting from gear into neutral. Thanks for your help!

 

[racerone]

Take it back to the shop.

 

[QBhoy]

Yeah. Check is it’s got a shift switch under the linkage at the engine. They are known to need adjustment certainly on the later models. Check the cables haven’t become too tight too.

 

[Csupp11]

Either the shift switch or tps (known for it) or the IAC perhaps. Former would be the favourite odds on, if it were me.

After many hours of troubleshooting, I found the rubber o-ring on the IAC (idle air control) valve had a cut in it! I decided to replace the IAC valve & new o-ring. That was the problem & it ran fine all summer!