Mercruiser forward to neutral cuts out!

blackrandomapple

blackrandomapple

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As above, when shidting from first to neutral the engine cuts out... Now i already know this is to do with the ignition cut out micro switch.. theres propbably a name for it but i think you'll get the idea!

My question is: What will happen if i bypass the switch so ignition doesnt cut out?

I already understand the way this works (cutting ignition to take preasure of gearbos to allow smooth change) but will it make much difference without the switch? It already has 2 or 3 clunks from the gearbox before it clicks into gear??

P.s Its a mercruiser 3.0 1993 with a alpha one drive!
 
IMO stay with the original set-up to keep the gear engagement as smooth as possible, it may also be worth checking the gear shift cable that runs from the engine mounted bracket into the leg itself because of its age, they will corrode and bind over time.
 
AndieMac said:
IMO stay with the original set-up to keep the gear engagement as smooth as possible, it may also be worth checking the gear shift cable that runs from the engine mounted bracket into the leg itself because of its age, they will corrode and bind over time.
Click to expand...

I have have done a heap load of work on the engine over the last few weeks including drive and all is fine, the only thing being the cable's are a little stiff but that shouldnt affect the way it works.. switch it engaging when i should but it still cuts out.. Unless you go from forward to reverse VERY slowly but when docking this isnt always possible and the engine cuts out. I may add this only happens when the boat is in the water, when on the trailer everything works fine!
 
No wait, i check all shifting mech in the drive and its all nice and easy, you can select forward reverse with ease directly on the drive, also shift cable from engine to drive is nice and easy... The only reason its stiff from throttle lever is (i think) stiff cable from lever to engine! Does that make sense?

Is there a way of lubing the the cables from throttle lever to engine? I do alot of work on motorbikes and its a simple job but there is no way (that i can see) of getting oil into the cable?

Would it make a difference to microswitch whether throttle is stiff or not tho?

Excuse me if im not making much sense but its late and im pretty tired!

:)
 
When you say you have done heaps of work to the engine etc., could you have made an adjustment to the cables at the engine mounted bracket near the micro-switch, it only has to be a turn or two out to make all the difference.
Was the shift control working fine before the work commenced? Engine mounted bracket alignment?
 
Agree to all said. Very often a question of adjusting cables.

You may find it impossible to disengage gear (go into neutral) if you remove the switch since the gears are designed to keep engaged at load.
 
AndieMac said:
Thanks for that link P, got that saved for a rainy day!
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LOL, would you believe that I actually found it now, only because many years ago I had a small lake boat with an Alpha leg, and saved it for the same reason? :)
In fact, she also suffered the same problem, but very rarely...
...and luckily, I sold the boat (to a mechanic, who already knew how to fix that) before it got worse, therefore I didn't have to put that procedure in practice.
The only thing I can add is that in my experience of those days, the Alpha shift seemed to work better, without grinding noises and with less motor stall, when the engage/disengage movement was very quick and determined.
Which takes a bit of practice though, particularly when engaging the gear: the movement has to be quick but short, to avoid having to deal with some MOB...! :D
Too bad that separate gear/throttle levers are so rare on outdrive boats...
 
if you bypass the switch you will not be able to deselect drive on the water.that means smashing into dock and probable serious injury to someone in the water.its a safety feature for gwetting from drive in forward or reverse back to neutral.a swift movement engages gear but the shift interrupt is for coming out of gear.
shift cable is the problem and needs to be replaced.and here's how to do it once the new one is installed.www.youtube.com/watch?v=-s_tgevX2aI
 
MapisM said:
LOL, would you believe that I actually found it now, only because many years ago I had a small lake boat with an Alpha leg, and saved it for the same reason? :)
In fact, she also suffered the same problem, but very rarely...
...and luckily, I sold the boat (to a mechanic, who already knew how to fix that) before it got worse, therefore I didn't have to put that procedure in practice.
The only thing I can add is that in my experience of those days, the Alpha shift seemed to work better, without grinding noises and with less motor stall, when the engage/disengage movement was very quick and determined.
Which takes a bit of practice though, particularly when engaging the gear: the movement has to be quick but short, to avoid having to deal with some MOB...! :D
Too bad that separate gear/throttle levers are so rare on outdrive boats...
Click to expand...

Aha! so this is why you don't like Alpha's :)

During this last season, spent mainly on a ski lake, I discovered an issue that while coming off the plane (to pick up people thrown out of towing tubes, far too often) the drive would 'jump' out of gear, from ahead to neutral, about one time in six, but still very annoying.

The engine and drive (Alpha-Gen 2) was just out of it's, from new, two year warranty when I took it to the mechanic, and he discovered a slight mis-alignment/distortion in the shift cable engine mounted bracket, which he replaced as a factory fault.
The problem was only discovered because of the skiing scenario, up until then the shift, to me, seemed absolutely perfect.
 
AndieMac said:
Aha! so this is why you don't like Alpha's :)
Click to expand...
Well, I wouldn't say that I don't like the Alpha - it's still better and more reliable than most VP outdrives, anyway.
The reason why I prefer the Bravo has more to see with power handling.
My train of thought being that outdrives are mostly good for going fast, and that demands high power.
My old lake boat with an Alpha mated to the 5.7 engine was a 22' Abbate.
Not too shabby, good for almost 50 kts, and pretty decent for monoski too.
But the Fountain with a big block mated to the Bravo XR which I bought a few years later (now also sold) was in an entirely different league.
Ok, bigger and heavier boat, so the comparison isn't actually fair.
But for stability at speed (where the difference was huge), I always thought that also the more solid outdrive played a role, particularly in jumps re-entry.
 
blackrandomapple said:
As above, when shidting from first to neutral the engine cuts out... Now i already know this is to do with the ignition cut out micro switch.. theres propbably a name for it but i think you'll get the idea!

My question is: What will happen if i bypass the switch so ignition doesnt cut out?

I already understand the way this works (cutting ignition to take preasure of gearbos to allow smooth change) but will it make much difference without the switch? It already has 2 or 3 clunks from the gearbox before it clicks into gear??

P.s Its a mercruiser 3.0 1993 with a alpha one drive!
Click to expand...

I think you misunderstand the purpose of this switch. It is fitted to immobilise the STARTER unless the engine is in neutral. I don t believe the ignition is wired through it! Certainly this is how it was on a Trojan 32 I sometimes tinkered with. :) The Trojan also had the problem of stalling sometimes and this was more often due to requiring TLC at the plugs points and mixture. Have you checked the auto chokes. Another thing that can cause the engine to stall on falling revs is a faulty low pressure oil cut out switch. This is wired to cut the ignition when the engine is running and the oil pressure falls to a set point. Maybe you have low oil pressure at tick over or tick over is too slow!

I seem to remember there are some good forums that deal with these engines.
 
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The OP's referring to the shift interrupter switch - designed to drop the engine revs super low to facilitate slotting the dogs in...

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