Engine won't shut off

86Bonanza

Cadet
Joined
Mar 9, 2007
Messages
11
Hey all. I have a 1986 Bonanza with a 4.3L OMC. I troubleshot a faulty alternator and replaced it. I am positive I got the connections right. After replacing the alternator (6 mos ago), I got a good charge, but the motor keept running after I turned the ignition switch to off. It was running smoothly and would respond to the throttle. I had to remove the accessory leads from the alternator to kill the motor. Now, after replacing my starter(last week), I have to remove the negative battery cable and the alternator accessory leads to get the engine to shut off. I know that the ignition switch is working correctly.

Any ideas?

Thanks.
Ben
 

tommays

Admiral
Joined
Jul 4, 2004
Messages
6,768
Re: Engine won't shut off

well pulling the battery or any alternator wire to shut it off kills the alternator :(

its much better to pull to pull the center wire form the distributor if you really have no other way to shut down .

you could just have a wire mixed up ? OR


If the alternator diodes are bad it can feed back power to the ingition through the purple wire (at least on a merc i do not no the OMC color ) which would keep it running with the key off





Tommays
 

Gary H NC

Fleet Admiral
Joined
Dec 1, 2005
Messages
8,972
Re: Engine won't shut off

Get you an original OMC factory manual.It has the wiring diagrams and color codes.Sounds like something is hooked up wrong.
Look on ebay,Searayman13 sells them.If you can't find one i have one i will sell for what i paid for it...
You can't beat the factory manual.
Don't waste your money on Seloc or Clymers..
 

jastacey

Petty Officer 2nd Class
Joined
Jan 25, 2004
Messages
173
Re: Engine won't shut off

You have a resistor problem on the D+ or igition terminial, if it's a Delco marine Alt. the resister is built in to the plug, what kind of Alt. do you have?
 

86Bonanza

Cadet
Joined
Mar 9, 2007
Messages
11
Re: Engine won't shut off

jastacey said:
You have a resistor problem on the D+ or igition terminial, if it's a Delco marine Alt. the resister is built in to the plug, what kind of Alt. do you have?

I replaced it with a delco automotive alt. If the resistor is built into the plug, then that may be my problem, I replaced the plug with the alternator...:devil:
 

jastacey

Petty Officer 2nd Class
Joined
Jan 25, 2004
Messages
173
Re: Engine won't shut off

Don't use that automotive Alt., it is NOT spark shielded, it will cause an explosion at the fuel dock or when enough vapors build-up in the bilge
 

86Bonanza

Cadet
Joined
Mar 9, 2007
Messages
11
Re: Engine won't shut off

Looks like I don't even have a choice, all of the auto alternators don't have the built in resistor. Is the starter "spark shielded" also, because I put a automotive starter on also.

Ben
 

jastacey

Petty Officer 2nd Class
Joined
Jan 25, 2004
Messages
173
Re: Engine won't shut off

Yes, the starter is spark protected, to prevent an explosion, you might want to check out Napa, they have a marine catalog and the common electricial stuff, like the stuff you've replaced, they have or they can get , and it isn't cheap, the reason is it is low production items
 

Reel Poor

Vice Admiral
Joined
Jan 29, 2005
Messages
5,522
Re: Engine won't shut off

Yes it is spark shielded also. All your electrical, ignition system, and fuel system are marine specific. Although some automotive parts will bolt on and usually work they are not USCG approved for the marine application
 

86Bonanza

Cadet
Joined
Mar 9, 2007
Messages
11
Re: Engine won't shut off

Well it looks like I will have to drive around with the engine cover off until I can afford the highway robery prices of marine parts. :/
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,581
Re: Engine won't shut off

No, you shouldn't be driving your boat around at all.

If you do, make sure it is only you on board.

When you fianlly replace your alternator with a marine one, measure the voltage at the coil to verify it is zero with the key off to make sure you are wired up correctly.
 

Reel Poor

Vice Admiral
Joined
Jan 29, 2005
Messages
5,522
Re: Engine won't shut off

I agree with Bruce. Your an accident waiting to happen.
Can you say......KABOOM ? ? ? :'(
 

86Bonanza

Cadet
Joined
Mar 9, 2007
Messages
11
Re: Engine won't shut off

bruceb58 said:
No, you shouldn't be driving your boat around at all.

If you do, make sure it is only you on board.

Lets think about this...the reason that the parts are "spark shielded" is because the motor is enclosed with very little air flow...correct? Well if the airflow was increased by exposing the engine to dissapate any fuel fumes, why would spark shielding be needed? It would be no different then the car motor it originated as.

I appreciate your concern, but you could loose the condescending tone.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,581
Re: Engine won't shut off

Well if the airflow was increased by exposing the engine to dissapate any fuel fumes, why would spark shielding be needed?
Becuase fuel vapors sink.

Think about what might happen if you had a slight fuel drip. These vapors will be produced as fast as you could posibly get them out with ventilaton.

I think common sense would tell you you would want everything spark shielded. But then again...
 

sabastianunf

Petty Officer 1st Class
Joined
Jun 11, 2004
Messages
215
Re: Engine won't shut off

A few dollars now could save your boat later. Wise up - keep it safe and yourself alive. I'd rather be surfing.
 

Gary H NC

Fleet Admiral
Joined
Dec 1, 2005
Messages
8,972
Re: Engine won't shut off

Ebay or ebasicpower,you can get the alt and starter for not much more than the automotive parts...
Why risk it?
There is a guy on ebay that parts out OMC engines all the time.Also i noticed a new marine starter for 79 bucks the other day..
 

86Bonanza

Cadet
Joined
Mar 9, 2007
Messages
11
Re: Engine won't shut off

Well I appreciate everyones information. I will look into replacing those parts.
 

ziggy

Admiral
Joined
Jun 30, 2004
Messages
7,473
Re: Engine won't shut off

I will look into replacing those parts.

great idea man. everyones tellin ya the truth man. boats with parts like ya've discribed can explode. yours and others safety is involved.....think about this. even with proper marine parts. yer still supposed to run yer blower 5 min. prior to turning the key to evacuate the bilge of fuel vapors.......

ya might consider a boater safety class too....they'll talk about just such things........
 
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