Engine won't cut off

[Nut]

Hi all. I have a Beta Marine 90 engine which is a year old with around 50 hours of running time. I have recently had my leisure batteries changed and my starte battery changed. Since doing this, the engine will not switch off with the stop button. The relay is clicking, but I have changed this anyway, but the engine still won't cut off. I have taken the solenoid off and passed a current through it and it worked, so I am at a loss as to what the issue could be. Can anyone help please?

[TrentePieds]

What solenoid?

The fuel interruption solenoid, which is what stops the engine, should have a little, clearly marked, lever on it that you can pull with a finger. Doing that mechanically interrupts the fuel flow and stops the engine regardless of what your electrics are doing.

On my Beta, which probably is fitted with the same engine stop solenoid, the little lever sez right on it: "Engine Stop"

With a "jumper" (a piece of 12-gauge wire long enuff and fitted with alligator clips on the ends) you can jump from a positive battery terminal to the only electrical stud on the engine stop solenoid. Doing that completes the circuit because the entire engine is already "gounded". If the solenoid is okay, it will activate when you do that, and the engine will stop. If it doesn't activate when you do that, you have a duff solenoid which is cheap to buy and easy to replace.

After that you can profitably spend your time chasing through your electrics and leaning how they all work and where and what their weaknesses are.


TrentePieds

[Nut]

Originally Posted by TrentePieds

What solenoid?

The fuel interruption solenoid, which is what stops the engine, should have a little, clearly marked, lever on it that you can pull with a finger. Doing that mechanically interrupts the fuel flow and stops the engine regardless of what your electrics are doing.

On my Beta, which probably is fitted with the same engine stop solenoid, the little lever sez right on it: "Engine Stop"

With a "jumper" (a piece of 12-gauge wire long enuff and fitted with alligator clips on the ends) you can jump from a positive battery terminal to the only electrical stud on the engine stop solenoid. Doing that completes the circuit because the entire engine is already "gounded". If the solenoid is okay, it will activate when you do that, and the engine will stop. If it doesn't activate when you do that, you have a duff solenoid which is cheap to buy and easy to replace.

After that you can profitably spend your time chasing through your electrics and leaning how they all work and where and what their weaknesses are.


TrentePieds

Thanks TrentePieds

Yes, it's the fuel interruption solenoid. I can turn the engine off by pulling the lever, but not with the stop button.

I have taken the solenoid off and jumped it from the battery and it worked (the lever shot out). The relay clicks when I press the stop button, so it seems the problem is between the solenoid and the relay.

[SailingHarmonie]

Vital to know to diagnose this issue...Is this by any chance an isolated ground engine? Does the battery negative cable connect directly to the engine block? Or does it go through a solenoid?

[FPNC]

Check that a ground wire for the solenoid was not left off the grounding stud.

[newhaul]

Originally Posted by Nut

Hi all. I have a Beta Marine 90 engine which is a year old with around 50 hours of running time. I have recently had my leisure batteries changed and my starte battery changed. Since doing this, the engine will not switch off with the stop button. The relay is clicking, but I have changed this anyway, but the engine still won't cut off. I have taken the solenoid off and passed a current through it and it worked, so I am at a loss as to what the issue could be. Can anyone help please?

Someone forgot to hook up a wire sounds like to me bet the solenoid will work properly if you directly feed it the 12v power the relay is not properly hooked up

[TrentePieds]

As I understand it, the solenoid is so wired that constant application of a smallish current will move the armature to withdraw a plunger from the fuel pump and hold the armature in the withdrawn position thereby permitting fuel to flow continuously, and therefore permitting the engine to run.

When the solenoid circuit is broken a spring-load on the plunger will advance it into the fuel pump which will then no longer pump, and the engine will stop.

That bit could, of course, work the other way about: The plunger is advanced INTO the pump to permit fuel to flow and the spring load withdraws the plunger. Whether it works one way or t'other, the electrics will be just the same.

The solenoid circuit takes it power from a so-called "latching" relay. When the key in the instrument panel is moved to the “run” position, the relay will close and "latch", i.e. energize itself via some circuitry native to it, so its contact points will stay in the "made" position and continue to energize the solenoid circuit. Thereafter the relay stays latched regardless of the key position and therefore once tarted the engine keeps running because the latched relay continues to energize the solenoid.

The relay now, in this condition, draws it power directly from the battery circumventing the key switch, which is why turning the key to "Off" will not stop the engine.

When you press the "Stop" button on the instrument panels, the circuit that holds the relay latched is broken. The relay therefore unlatches, and thereby breaks the circuit to the solenoid so it no longer can withhold the plunger from the pump. The spring-loaded plunger now advances into the pump causing it to stop pumping and therefore the engine to stop.

If that understanding is correct, the "stop" button would have to be a "normally made" switch.*The negative connection of the solenoid is almost certain to be through the engine block.

I think, since you say that both solenoid and relay work when you bench test them, that you have a simple wiring problem such as sloppy terminal fitting.

Hope I'm right and that the above helps. If I'm wrong, one of our sparkies will pick me up on it :-)!

TP

[newhaul]

Originally Posted by TrentePieds

As I understand it, the solenoid is so wired that constant application of a smallish current will move the armature to withdraw a plunger from the fuel pump and hold the armature in the withdrawn position thereby permitting fuel to flow continuously, and therefore permitting the engine to run.

When the solenoid circuit is broken a spring-load on the plunger will advance it into the fuel pump which will then no longer pump, and the engine will stop.

That bit could, of course, work the other way about: The plunger is advanced INTO the pump to permit fuel to flow and the spring load withdraws the plunger. Whether it works one way or t'other, the electrics will be just the same.

The solenoid circuit takes it power from a so-called "latching" relay. When the key in the instrument panel is moved to the “run” position, the relay will close and "latch", i.e. energize itself via some circuitry native to it, so its contact points will stay in the "made" position and continue to energize the solenoid circuit. Thereafter the relay stays latched regardless of the key position and therefore once tarted the engine keeps running because the latched relay continues to energize the solenoid.

The relay now, in this condition, draws it power directly from the battery circumventing the key switch, which is why turning the key to "Off" will not stop the engine.

When you press the "Stop" button on the instrument panels, the circuit that holds the relay latched is broken. The relay therefore unlatches, and thereby breaks the circuit to the solenoid so it no longer can withhold the plunger from the pump. The spring-loaded plunger now advances into the pump causing it to stop pumping and therefore the engine to stop.

If that understanding is correct, the "stop" button would have to be a "normally made" switch.*The negative connection of the solenoid is almost certain to be through the engine block.

I think, since you say that both solenoid and relay work when you bench test them, that you have a simple wiring problem such as sloppy terminal fitting.

Hope I'm right and that the above helps. If I'm wrong, one of our sparkies will pick me up on it :-)!

TP

On that particular kubota engine the solenoid is energized to shut the fuel off and shut down the engine . But yes there is some electrical issue in the wiring .

[Tsuru]

I've had the stop button fail on our Beta 60. Fortunately we have 2 (1 @ helm 1@ engine panel). I removed the button and cleaned the contacts and it worked for a short time. Replaced with new and no issues since.
Good luck,

[newhaul]

Originally Posted by Tsuru

I've had the stop button fail on our Beta 60. Fortunately we have 2 (1 @ helm 1@ engine panel). I removed the button and cleaned the contacts and it worked for a short time. Replaced with new and no issues since.
Good luck,

And a piece of shark leader cable for the emergency pull to shut down if all else fails .