Mercruiser 3.7 Not firing.

[Chado339]

I have a mercruiser 3.7 liter 165 hp 4 cylinder engine in my chaparrel. I got it from a family member recently. Its been sitting for over a year. Got it home and cant get it started. I replaced the battery with a new napa marine battery. Tried starting it and it will only turn over I cant get it to fire. Pulled the plugs and no spark. Got pissed and grabbed the coil wire nothing there either.

Replaced the coil and still no spark. Can someone please tell me what else i should be looking at or doing or what the problem can be.

Chad

 

[83Evinrude]

Re: Mercruiser 3.7 Not firing.

Is there voltage getting to the coil?

I believe one side goes to the battery and the ground is provided by either the points or electronic ignition module in the distributor. You could also pull the top off the distributor and make sure the rotor is turning, I believe that would verify if the timing chain and gears are intact.

 

[Chado339]

Re: Mercruiser 3.7 Not firing.

The positive wire on the coil I was able to follow back to the starter solonoid. My neighbor but a multimeter on it the other day and he said i was getting juice to it. The negative side has to two wires on it a gray one that goes back into a harness and a black one that goes to the distributer. Have no idea were the gray one goes. I have no juice comin out of the coil at all. Ill pull the cap and make sure the button is moving.

 

[bruceb58]

Re: Mercruiser 3.7 Not firing.

The positive side should have two wires going to it. One goes to the starter solenoid and has 12V on it while cranking. The other should go throuh a resistor wire and has 12V onit while ignition is on.

 

[Chado339]

Re: Mercruiser 3.7 Not firing.

Okay my mistake I do have two wires coming from the positive side. I just went out and pulled the distributer and the button moves. so gears and timing chain are fine. I pulled the coil cable off the distributer and was able to see a weak spark jump off it to a bolt of the ground. What does this mean? Points? What should I try next?

On another note what is the little plastic resevoir for on the front of the engine. Its empty, so im not sure what goes in it. Ive never had in inboard before so im learning as i go.

 

[Bt Doctur]

Re: Mercruiser 3.7 Not firing.

1 Remove the grey wire from the neg side of the coil
2 remove dist cap, run some fine sandpaper across the points, check point gap, .018(a matchbook works), test for spark
If it runs: Do a full tune up including new points,(Blue-Streak DR-2240X)

 

[sdoomaha]

Re: Mercruiser 3.7 Not firing.

You have a closed cooling system. The little plastic reservoir is an overflow for coolant. You would be well served to go up to the adults sticky at the top of the forum and download the manual for your motor and drive. Spend a couple hours reading thrugh it and you will have a excellent starting point and basic knowledge of your motor and drive.

Good Luck with your spark issue.....

 

[Thumbtack]

Re: Mercruiser 3.7 Not firing.

I almost always have to file the points real well on all my 4-cyl. engines after they sit for extended periods, after that they start right up and run good till they sit again.

 

[Chado339]

Re: Mercruiser 3.7 Not firing.

Ok so I figuired out that my spark issue is probably a breaker point. I did a little test that my book told me to do with putting an insulator between the point and rubbing my screwdriver over the arm grounding it to the plate and low and behold I got my spark. I got a tune up kit that includes new points and condenser and cap. Im hoping that will rememdy that issue.

Thanks for all the help.

Chad