Engine won't shut off?

[Mercs and such]

I managed to get my motor running but it doesnt turn off without pulling the choke. The black/yellow wire is disconnected from the switchbox because when i make contact the engine shuts off however the key doesnt shut it off and i want it to do it that way!! There is 1 black/yellow and it branches off into 2 black/yellow's. One goes to the switchbox but shuts off the motor and the other???

Any suggestions on how to get it working?

Also my bottom carb doesnt get fuel. Is it possible that the reason my plug wires for #3, #4 are grounding before they can fire the pistons as a safety precaution? or is something causing it to ground? i electrical taped the wires but its off and on sparking.

 

["G"]

Re: Engine won't shut off?

Consult your merc manual wiring diagram. There are some very pointed answers to your questions.

 

[Mercs and such]

Re: Engine won't shut off?

thanks G. I have the clymers manuel and all it has is the wiring diagram no troubleshooting on it. Im wondering if it has to be grounded to the cowl frame. BTW, the engine is a 1984 75hp 4cyl. brownband

 

[saumon]

Re: Engine won't shut off?

As G said!

And BTW, running an engine when some cylinders doesn't get fuel also mean they doesn't get ANY oil, wich is a pretty sure way to seize it!

Ditch the Clymer and get an OEM Service manual. Probably the best investment you can made.

 

[sschefer]

Re: Engine won't shut off?

Ditch the Clymer and get an OEM Service manual. Probably the best investment you can made.

Ahmen!

 

[achris]

Re: Engine won't shut off?

...Ditch the Clymer and get an OEM Service manual. Probably the best investment you can made.

He was told that about a week ago... HERE, but said he thought it was too expensive...

It would have paid for itself by now.

The black/yellow wire is supposed to be connected to the power pack, that is how the engine is turned off. If it's turning the engine off (not not allowing it to start), then you need to fault find the stop circuit. Start with the tilt switch... You'll find it in the manual... Ar, sorry, forgot, no manual... time to take a trip to the library? Or maybe BUY THE MANUAL!

Chris......

 

[zach103]

Re: Engine won't shut off?

check your fuel like to that carb. are you geting gas into the bowl at all?

 

[Mercs and such]

Re: Engine won't shut off?

zach103 it does get fuel in the line. It shoots out when taken off the fuel inlet but no there is no gas getting into the carb. I have ordered a new float/ needle kit hop that helps. I think maybe the float is set to high so no gas can come in

Achris i'm going to go take a trip to the library for that manuel.


saumon, the engine has only been running off of the top 2 bc i have only been running the engine at idle but the bottom 2 are still moving so im curious as to how it gets lubricated but i have been running it for about 3 hours straight with no signs of problems aside to the wires on cyl. 3,4 discharging on the throttle arm so no spark to the bottom 2 plugs still trying to figure that out.

There is obviously a short circuit in the kill wire somewhere because it supplies no spark when attached to the switchbox

 

[saumon]

Re: Engine won't shut off?

saumon, the engine has only been running off of the top 2 bc i have only been running the engine at idle but the bottom 2 are still moving so im curious as to how it gets lubricated but i have been running it for about 3 hours straight with no signs of problems aside to the wires on cyl. 3,4 discharging on the throttle arm so no spark to the bottom 2 plugs still trying to figure that out.

Now you say that there's no spark at the bottom 2 but how could you know that they're not getting gas also?

 

[Mercs and such]

Re: Engine won't shut off?

well, I observed it at night and saw the bottom 2 plugs lighting up in sparks and not even getting any spark to the actual cylinders. Why does it do that?? I electrical taped the wires and that seemed to do nothing the whole wires light up in a ring of blue all the way down to the spark plugs which they just discharge on the common ground.

 

[saumon]

Re: Engine won't shut off?

OK, reread my question: aside from not having sparks, how can you know that bottom carbs aren't getting fuel?

 

[Mercs and such]

Re: Engine won't shut off?

well the carb is bone dry aside to the top which is wet with fuel and the primer bulb when squeezed, the bottom carb doesn't flow gas out of the plug in the fuel bowl only from the top and when i take the line off the bottom, gas spews from it without any going into the carb.

 

[saumon]

Re: Engine won't shut off?

Time to clean them (probably a stuck needle) before ruining your engine cause, as said, no fuel in a cylinder also mean no oil at all.

And there's absolutely no relation between this (no gas to bottom carbs) and your electrical problem (bad sparks at #3 and #4)

If you had a manual, you would know that a good diagnosis include, in this particular order,:

1 - a compression test (it's useless to try chasing fuel problems or electrical gremlins if a hole is shot)
2 - checking that you get a STRONG spark at each cylinder (being able to jump a 1/2' gap)
3 - then checking the fuel flow

 

[Mercs and such]

Re: Engine won't shut off?

compressions good, it seems when i spray gas into carb #2 the rpms pick up so i now believe it gets spark but it just discharges as well on the throttle arm so i still dont know how to correct that.

As for the carb, i have ordered a new needle kit and float kit, the carbs have just been serviced but i guess they didnt put it back together right. Besides i have already had my ways with the mechanic and im not taking it back there.


so as i say again,

i need to figure out why the wires discharge, no fuel gets to the carb, and why the kill wire kills the engine when i apply it to the switchbox.

 

[Lone Duck]

Re: Engine won't shut off?

Where on the switch box are you connecting it ?

 

[Mercs and such]

Re: Engine won't shut off?

on the "blk-yel." terminal on the switchbox its on the left row i think it is the 4th or 5th post down.

When i dont have it hooked up, motor runs amazing, when i have motor running and i make contact with the wire and post it sparks then engine stops. It is on the right post its just when it is,

there is no spark what is going on here? any help.

 

[sschefer]

Re: Engine won't shut off?

The black and yellow wire is doing exactly what it's supposed to do if:

1. The ignition switch is off.
2. The safety lanyard is not engaged in the safety switch.
3. The little black mercuy switch on the electrical plate by the starter solenoid is either bad or loose and has fallen out of adjustement.
4. Your engine is tilted full up.

Just start following the black wires with the yellow stripe back to their homes and sooner or later you'll find out where it's shorted to ground. And yes, that is the only way to do it, no miracle cure this time.

Maybe if you save this to your computer and zoom in on it you can figure it out.

 

[Mercs and such]

Re: Engine won't shut off?

The black and yellow wire is doing exactly what it's supposed to do if:

1. The ignition switch is off.
2. The safety lanyard is not engaged in the safety switch.
3. The little black mercuy switch on the electrical plate by the starter solenoid is either bad or loose and has fallen out of adjustement.
4. Your engine is tilted full up.

Just start following the black wires with the yellow stripe back to their homes and sooner or later you'll find out where it's shorted to ground. And yes, that is the only way to do it, no miracle cure this time.

Maybe if you save this to your computer and zoom in on it you can figure it out.

Thanks for the pic!! it looks to me like a 115hp i can probably trace it back but i have a 4 cyl. its a 75hp. Thank you sschefer I think it might be the wrong ground.

 

[sschefer]

Re: Engine won't shut off?

That's actually a V-6 135/150/175/200

Hows this -

 

[turbinedoctor]

Re: Engine won't shut off?

I feel confident you have three different problems here and they need to be looked at one at a time. One is fuel delivery to the bottom carb, second is spark to the bottom two plugs and third is the kill switch circuit.

First you need to correct the fuel delivery problem to the lower carb. Take the top off the carb and see if the needle valve is stuck closed. You should be able to turn the top of the carb upside down then right side up and see the needle valve move freely open and closed. As stated earlier no gas means no oil. There is probably enough oil residue in the bearings and rings for a little protection for a short while but it will quickly give up if run for long enough.

Second if there is no spark to the lower two plugs but it is sparking to the throttle arm or anywhere else, replace the plug wires. You should not see any sparks coming from the wires them selves. the plug needs all the fire they can get and if there is any fuel leak near by you may end up with a fire.

Third is the kill circuit. Use the wiring diagram provided earlier to help trace it down. Using a ohm meter connect one lead to the black/yellow wire and the other to engine ground with the ignition switch in the run position. If you read anything other then open, you have to find out where it is. One by one start disconnecting wires to device that would and should kill the engine. I.E. mercury tilt switch, Lanyard kill switch or the black/yellow wire at the ignition switch. There maybe more but these are the first that come to mind.

Hope this helps,
Durwood