Yamaha F70 dies when putting in gear

[Bluedog1962]

I have a 2017 Yamaha F70 four stroke that recently began cutting out when it is put in forward.

It starts and idles great. It will go into reverse great. But whether I ease it into or slam it into forward it will cut out completely. Like a switch was cut off. It will start right back up with no problem.

[Bluedog1962]

Does no one have any insight?

[99yam40]

I would monitor fuel pressures to make sure they stay in spec,
and check injectors.
sending them off to be flow tested and cleaned may help if the pressures are OK
Motor needs more fuel under load,
forward puts a lot more load on a motor than neutral and reverse.
have you changed any filters and looked to water or bad fuel
just my guesses

[DennisG01]

Kinda sounds like a neutral safety switch? I say this without knowing a whole lot about this stuff like some of the guys on this forum. But I believe you have a switch somewhere around the shift shaft - it won't allow the engine to start in gear. If that mechanism is goofed up, when you put it into FWD, maybe it's sticking or not moving correctly. Take a look at the switch mechanism while someone shifts - you may be able to tell what's happening just by looking closely.

[DennisG01]

Adding to above... am I mistaken on how the neutral safety switch works? Meaning, once an engine is started, does it (can it) have any effect on the engine staying running?

[pstephens46]

If the neutral switch engages wouldn’t you expect the alarm to sound? Other words, If I try to start my F150 in gear, the alarm will sound.

[DennisG01]

If the neutral switch engages wouldn’t you expect the alarm to sound? Other words, If I try to start my F150 in gear, the alarm will sound.

You know what, I don't rightly know if my engine sounds an alarm or not - although it's an OX66. I've never tried it! I was just kinda thinking out loud there as it sure seems like something electrical is going on - some wonky switch/sensor. I first thought of a shift interrupt switch, but I don't think OB's have them (like stern drives do)? I've personally seen (numerous times) shift interrupt switches cause this exact scenario, but if I'm right that OB's (or at least this particular OB) don't have that, then what other switch/sensor is related to shifting and engine power?

Edit: Disregard what I just said. I know what you mean, now. The alarm that we hear whenever we first turn the key to "on" but before starting, right?

[walleye1]

get a sm and check the shift switches

[TownsendsFJR1300]

If the neutral switch engages wouldn’t you expect the alarm to sound? Other words, If I try to start my F150 in gear, the alarm will sound.

I don't get an alarm while starting in gear my F150..

Turn the key to crank and nothing, nothing happens (as it should).. NO alarms..

[pstephens46]

I don't get an alarm while starting in gear my F150..

Turn the key to crank and nothing, nothing happens (as it should).. NO alarms..

Yep. You are right. Brain fart.

[99yam40]

neutral start switch should be in the con*****er,
but there should be some switches on the motor itself that tells the ECU when the gears are shifted.
I have no idea what they do on F70.
on some it is to help take the motor out of gear

[DennisG01]

on some it is to help take the motor out of gear

That's the question I was wondering about above. Do OB's have a shift interupt switch? Some stern drives do (not all), but I wasn't sure about OB's. I believe it has more to do with the type of gears being used, though. I have seen a shift interupt switch cause this EXACT problem on a stern drive (quite a few times) - just don't know enough about the OB's (yet) to say with any certainty.

[99yam40]

from what Rodbolt has written in the past, the larger outboard motors do, but I do not know if the F70 does