74 mercruiser 140 operation questions

AEROCOOK

Master Chief Petty Officer
Joined
Jul 28, 2004
Messages
872
I just bought a 1974 19' Starcraft aluminum bowrider with a Mercruiser 140. I have owned many outboards over the years but this is my first I.O. and I have some questions about operating the unit.
What is the starting procedure? Is there a choke and if so where is the switch for it located?
If someone has a simillar vintage mercruiser and wouldent mind helping me get aquainted I would really appreciate it.
 

SpinnerBait_Nut

Honorary Moderator Emeritus
Joined
Aug 25, 2002
Messages
17,651
Re: 74 mercruiser 140 operation questions

Better answered in the Mercruiser/Volvo/OMC I/O and Inboard troubles and repair forum.
 

Alumarine

Captain
Joined
Feb 22, 2005
Messages
3,738
Re: 74 mercruiser 140 operation questions

On my 74 there is a black button at the bottom of the control lever (I have a single lever setup).

You push that button in which allows you to move the lever in the throttle only mode (the gears will not engage).

As you probably have a manual choke you should pump the throttle a couple of times to set the choke and keep the lever pushed forward a bit to keep the revs up.

Once it starts and is idling well you can bring the lever back to the middle position which will disable the throttle only mode.
 

AEROCOOK

Master Chief Petty Officer
Joined
Jul 28, 2004
Messages
872
Re: 74 mercruiser 140 operation questions

Thanks for the reply marc c.
I was wondering about that knob at the bottom of the throttle lever, now I know.
I think you meant automatic choke when you said "Manual"?
You indicated that you pump the throttle a couple of times to activate the choke (same as a car without fuel injection) and I assume it turns it's self off when the motor is warm? There is no manual button identified as choke.
 

Alumarine

Captain
Joined
Feb 22, 2005
Messages
3,738
Re: 74 mercruiser 140 operation questions

Yes, I meant automatic. It's not an electric choke.

The choke should open fully when the engine is warm.

Thanks for the reply marc c.
I was wondering about that knob at the bottom of the throttle lever, now I know.
I think you meant automatic choke when you said "Manual"?
You indicated that you pump the throttle a couple of times to activate the choke (same as a car without fuel injection) and I assume it turns it's self off when the motor is warm? There is no manual button identified as choke.
 
Top