150 4stroke Hard to shift after 10-15 min run

[Norman P Hebert]

After a run back to the landing of about ten to fifteen minutes at close to WOT my 150 Merc 4stroke is very difficult to shift. We noticed that the RPMs were running about 1400 which obviously is the reason why it won't shift. This is the third time i fished all day with no problems and when i got back to the landing after a longer than normal run, the problem occurs. Why is my throttle seemingly "stuck" at this higher than shifting range only after the longer runs? Serial No. of motor 2B245490.

[hanker71]

do you have a hotfoot?

[Norman P Hebert]

Yes I do and that is one of the first things I checked and it is not sticking.

[Nailbender8]

do you have a hotfoot?

I thought the exact same thing...

[EuropeanAM]

Please take a moment to review the Forum Announcements, and provide the Required Info with your post. Thanks!

[davidwademarine]

After a run back to the landing of about ten to fifteen minutes at close to WOT my 150 Merc 4stroke is very difficult to shift. We noticed that the RPMs were running about 1400 which obviously is the reason why it won't shift. This is the third time i fished all day with no problems and when i got back to the landing after a longer than normal run, the problem occurs. Why is my throttle seemingly "stuck" at this higher than shifting range only after the longer runs? Serial No. of motor 2B245490.

We are in Baton Rouge if we can help you out. Will return back from the holidays on Monday.

[Norman P Hebert]

OK sorry, I have a 2016 Mercury 150 HP 4stroke Serial No.2B245490, at approx. 5800 RPM's at WOT, running a 24P Tempest prop. Water Pressure runs about 5lbs at idle and around 36 lbs. at WOT using analog instruments. Thanks

[EuropeanAM]

Check hotfoot setup. Make sure spring is returning throttle consistently to idle position throughout the range of steering and usable trim range.

[Norman P Hebert]

Thank you very much, but I'm not certain what you mean by "usable trim range"

[kry29]

The usable trim range is the slow trim portion of the tilt and trim system.

[MichaelJ3]

The usable trim range is the slow trim portion of the tilt and trim system.

150 Four Stroke has Single Ram (and speed) tilt/trim (at least I don't think there is a model that has 2 stage tilt/trim unit)

I believe what Don is referring to is the Trim range from full down to where either the trim limit stop is or where you blow out, whichever is lower, but for all practical purposes is likely at the trim stop

(Trim Stop is the point at which, while underway and of sufficient RPM's, you can't trim up any more. You can TILT up more than this when at idle, or of course in neutral or with the key switch off).

Don, let me know if I didn't explain that right.

[Norman P Hebert]

So maybe I didn't have the motor trimmed fully all the way down and at this height the rpm's were higher ?. Do I just make sure that my motor is trimmed down fully or does my hot foot need adjusting to the "usable trim range"

[mikesxpress]

Make sure the angle/trim is not binding the hotfoot cable.

[MichaelJ3]

Do I just make sure that my motor is trimmed down fully or does my hot foot need adjusting to the "usable trim range"

You want your hotfoot to always return your motor to Idle, regardless of the motor position (for sure within usable trim range, but ideally always). So, if the issue is that at certain trim or steering angles, the hotfoot cable is binding/sticking, you need to adjust it. I think that is what Don and Mike are saying.

If you don't always return to idle, it is a safety issue because, like you experienced, you can't shift...or stop...

[EuropeanAM]

You want your hotfoot to always return your motor to Idle, regardless of the motor position (for sure within usable trim range, but ideally always). So, if the issue is that at certain trim or steering angles, the hotfoot cable is binding/sticking, you need to adjust it. I think that is what Don and Mike are saying.

If you don't always return to idle, it is a safety issue because, like you experienced, you can't shift...or stop...

+100

And this can also cause faults under certain circumstances (potentially with Engine Guardian).

[Norman P Hebert]

Okay, I've learned a lot but now I am not knowing what Engine Guardian is. Thanks everybody for your help!

[EuropeanAM]

Engine Guardian is described in the Owner's Manual (it is the Logic/Programming within the PCM, that attempts to protect the engine by limiting your available power when faults occur that could be detrimental to the engine).

[Norman P Hebert]

Thanks again, I will have the hot foot looked at.

[MichaelJ3]

Thanks again, I will have the hot foot looked at.

Did you ever get a resolution? Curious what it was.

[davidwademarine]

Did you ever get a resolution? Curious what it was.

Norman brought his boat to us last week and we got his problem resolved. The throttle cable at the engine and the HotFoot idle stop screw were out of adjustment.