1987 mercruiser wont start with choke.

[Clarko1988]

hello all i cant seem to start my boat with the choke on this is a 4.3 mercruiser with mercarb. it has been fully rebuilt. it starts with the choke open but not with it closed. also the boat only starts when i let off the key at the ignition.

 

[alldodge]

also the boat only starts when i let off the key at the ignition.

Have 2 problems but fixing this one will probably fix the other. Being a 1987 it would have TB-IV ignition. First thought would be the ignition switch.

Put a voltmeter on the + side of the coil.
Disconnect the small Yellow/Red wire from the slave solenoid so the starter won't crank. This will keep the starter from cranking. Then turn the key to start and see if 12V is still there

 

[alldodge]

Note: If you have points distributor and not TB4 (TB4 came out in 1982)

With points there is a wire coming from the starter solenoid to the + side of the coil. This wire powers the coil when the motor is cranking. If you have points then check this connection

 

[kenny nunez]

Get a 12 volt test light or a volt meter and have someone turn the key to start while you probe the + side of the coil. If there is low or no voltage then the bypass circuit in the slave solenoid may be the problem.

 

[Clarko1988]

Get a 12 volt test light or a volt meter and have someone turn the key to start while you probe the + side of the coil. If there is low or no voltage then the bypass circuit in the slave solenoid may be the problem.

 

[alldodge]

The solenoid Kenny is talking about is part of the starter. That's the slave solenoid which is what I was talking about. The yellow/red wire on the bottom of it is wire I mentioned

Do you have a distributor with points or electronic?

 

[kenny nunez]

The wire you are looking for is on the 9 o’clock position outboard side of the starter slave solenoid, that is the one that feeds the + side of the coil while in cranking mode.

 

[Clarko1988]

Got. Also you happen to know what the starting point is on air fuel mixture screw on carb?

 

[alldodge]

From bottom out, back out 1 1/2 turns out

 

[kenny nunez]

Most times 1.5 turns from lightly seated.