mercruiser 4cyl

[serrato]

I just bought a 1987 boat with 4cyl Mercruiser engine. I think its a 3.7 alpha one engine. Im not getting any spark. Im getting 10 volts on the + side of coil and then about 6volts when cranking. The boat has been sitting for 2 yrs. could the condensor and points be the problem? The boat was left outside with out covering. any suggestions.. victor

 

[Bondo]

Re: mercruiser 4cyl

could the condensor and points be the problem?

Ayuh,....... Do a Tune Up,+ maybe it'll Start.....

 

[kd7isf]

Re: mercruiser 4cyl

Sounds like the points to me. Replace the condensor and points as a set.

Hope this helps

 

[roadrash]

Re: mercruiser 4cyl

I believe you have the same engine and problem i had. look at my post, should be helpfull

 

[Reel Poor]

Re: mercruiser 4cyl

Six volts at the coil when cranking sounds low. Check the wire from terminal D on the starter solenoid to the positive side of the ignition coil. This wire should supply battery voltage to the coil while cranking. What is the battery voltage while cranking ? (your volt meter on Batt + terminal and Batt - termnial)

 

[serrato]

Re: mercruiser 4cyl

Terminal D has no wire. I do however have a wire from a solenoid mounted near the starter that looks to be the same color as the one on the coil. It reads 6 volts when tested.

Does anyone happen to know what the resistance (ohms) should read on the coil. I want to know if this is a good way to test the coil. thanks....

 

[Reel Poor]

Re: mercruiser 4cyl

Terminal D has no wire. I do however have a wire from a solenoid mounted near the starter that looks to be the same color as the one on the coil. It reads 6 volts when tested.

To prove if this may be a problem you can run a jumper wire from the battery positive terminal to the coil positive terminal and see if the engine will start.

BTW.....Did you check the battery voltage while cranking ?

 

[serrato]

Re: mercruiser 4cyl

I tried jumping the coil and still no spark. When cranking over, im getting about 11 volts. Could I have a 6volt system or some kind of resistor that reduces my voltage/

 

[Bondo]

Re: mercruiser 4cyl

Could I have a 6volt system or some kind of resistor that reduces my voltage

Nope,..... 6 volts is Too Low, Even With the Resistor,......

And,.... When Starting,.....
The Wire from the Starter that RP showed you,...
By-Passes the resistor,+ sends the Full 12 Volts to the Coil to Start it.....