Merc 3.0 spits sputters dies when going into neutral

jjcarroll1

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Not sure what's going on. Merc 3.0 starts runs fine all day except when I shift into neutral - it's stumbles and dies , unless I can slip it out of gear quickly and throttle up. Starts right up after it dies. Makes it tough coming up to a dock etc. thanks any ideas?
 

alldodge

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Need to try adjusting your shift interruptor switch first. If that works then your good to go. If that is no help then need to replace the shift interruptor switch.

 

Rick Stephens

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Lower shift cable is the top suspect.

The lower shift cable is a wear item. The inner cable wears out the outer housing and drags putting pressure on the shift interrupt switch. Lower shift cables need replacement on a periodic basis. Yours needs replacing.
 

alldodge

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Lower shift cable is the top suspect.

The lower shift cable is a wear item. The inner cable wears out the outer housing and drags putting pressure on the shift interrupt switch. Lower shift cables need replacement on a periodic basis. Yours needs replacing.
Have to agree
 

jjcarroll1

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Lower shift cable is the top suspect.

The lower shift cable is a wear item. The inner cable wears out the outer housing and drags putting pressure on the shift interrupt switch. Lower shift cables need replacement on a periodic basis. Yours needs replacing.
Lower shift cable was just replaced last week
 

Rick Stephens

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From everything you said was happening, the lower shift cable is either not routed correctly, which adds a lot of tension, plenty enough to activate the shift interrupt. Or the shift linkage adjustments are not correct.

It also can be aftermarket chinesium shift cable-itis. That is if an aftermarket cable was installed.

You might disconnect at the motor end and hand shift. Should be super easy to move on land and butter smooth.

Unfortunately, that doesn't tell us much about shifting out of gear in the water. In that case the prop is turning and loads the drive train. The shift interrupt grounds the ignition until the drive train and the gears unload allowing it to come out of gear. If anything is grabbing or maladjusted, the motor will die before the gears go into neutral.

BTW, stating you just replaced the lower cable would have been useful to know in the first post..
 

jjcarroll1

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May 5, 2022
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From everything you said was happening, the lower shift cable is either not routed correctly, which adds a lot of tension, plenty enough to activate the shift interrupt. Or the shift linkage adjustments are not correct.

It also can be aftermarket chinesium shift cable-itis. That is if an aftermarket cable was installed.

You might disconnect at the motor end and hand shift. Should be super easy to move on land and butter smooth.

Unfortunately, that doesn't tell us much about shifting out of gear in the water. In that case the prop is turning and loads the drive train. The shift interrupt grounds the ignition until the drive train and the gears unload allowing it to come out of gear. If anything is grabbing or maladjusted, the motor will die before the gears go into neutral.

BTW, stating you just replaced the lower cable would have been useful to know in the first post..
Ya I didn't even think that would be the cause of it. I changed it cuz I couldn't get it in fwd/reverse it was either one or the other. I was thinking to increase idle on carb? As far as routing the cable I guess I'm not sure if it's right or not, couldn't find anything stating exactly how to route it. But I feel like I did best knowing it couldn't be sharp corners etc. thanks
 

dubs283

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I was thinking to increase idle on carb? As far as routing the cable I guess I'm not sure if it's right or not, couldn't find anything stating exactly how to route it.
No, the carb (at this point) isn't the cause of your issue.

3.0L uses a couple different routings for the lower shift cable depending on vintage/location of shift plate on the motor. Post your engine serial number/photos of the engine and shift plate and we can try to help more

To satisfy my curiosity, did you use an oem or aftermarket cable assembly and adjust properly?
 

jjcarroll1

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No, the carb (at this point) isn't the cause of your issue.

3.0L uses a couple different routings for the lower shift cable depending on vintage/location of shift plate on the motor. Post your engine serial number/photos of the engine and shift plate and we can try to help more

To satisfy my curiosity, did you use an oem or aftermarket cable assembly and adjust properly?
Yes OEM cable and this group helped get the adjustment right, I only say it's right cuz it shifts into forward and reverse.
 

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dubs283

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Yes OEM cable and this group helped get the adjustment right, I only say it's right cuz it shifts into forward and reverse.
If you're achieving full forward and reverse and are sure the adjustment is correct you can start to look at first the shift interrupt switch and associated parts. Mainly the switch itself, the v notch and v spring assy. Verify it is engaging only when shifting from gear (either) into neutral and does so swiftly so as not to "hang up" and cause the ignition to stall too long. There is an updated stiffer v spring that can help the return to the run/static position if this is the case

Next would be the question of tune up, fuel filter inspection/replacement and fuel delivery
 

jjcarroll1

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Joined
May 5, 2022
Messages
37
If you're achieving full forward and reverse and are sure the adjustment is correct you can start to look at first the shift interrupt switch and associated parts. Mainly the switch itself, the v notch and v spring assy. Verify it is engaging only when shifting from gear (either) into neutral and does so swiftly so as not to "hang up" and cause the ignition to stall too long. There is an updated stiffer v spring that can help the return to the run/static position if this is the case

Next would be the question of tune up, fuel filter inspection/replacement and fuel delivery
Thank you. I'll check all that. Appreciate it.
 
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