Mercruiser 4.3L Won't Crank

[cringe]

2002 4.3L V6 Mercruiser 190HP serial number 0M092704

Engine will not crank. Last used boat 3 weeks ago. I turn the key and get a single click from the starter relay switch beside the 50A breaker. Kill switch is in RUN position. Battery is a month old 12.6V, terminals are clean, wires secure. Hand throttle is in neutral. 50A breaker has 12.5V on each side, was replaced 1 year ago. Blower and bilge rocker switches have power. Starter relay switch (slave solenoid) is now new since I thought that was the issue, still get a single click when I turn the key (ugh). Engine was slow to crank this summer. After warm up, it would crank right over again. Lake is fresh water, not salt.

I'm suspecting the starter solenoid or starter or corroded wiring/connectors at this point. The orange wire into the back of the alternator has 12.5V. I will test both sides of 90A fuse for 12.5V soon. I plan to remove wires from starter solenoid (if I can reach them!), clean them. Any other advice? I am not original owner of boat but I suspect the starter solenoid and starter are original. How do I "hot wire" the starter solenoid and starter to test engine for any crank at all? Is there a obscure fuse somewhere? Any other ideas?

And do I have these wires labeled correctly? Thanks.

 

[achris]

Check for voltage on the red/yellow coming off the slave solenoid when you turn the key. You're wires are labelled correctly.

Chris....

 

[Bt Doctur]

and get a single click from the starter relay switch beside the 50A breaker. Kill switch is in RUN position. Battery is a month old 12.6V, terminals are clean, wires

Jump the 2 large lugs, starter should spin the motor . If no response, check cable connections both pos and neg at battery and where they connect to the motor , If there secure and clean then have the starter and solenoid checked/repaired/replaced

 

[cringe]

I cleaned the connections on the starter solenoid but they were already in good shape really. Battery terminals and wires are fine.

I have 12.5V before and after the 90A fuse. The yellow/red wire from slave solenoid has 11.8V on the starter solenoid small stud when key is turned to start and get the single click. And 12.5V between large studs on starter solenoid. I jumped the large studs on starter solenoid with a wire, nothing except a few sparks. Then with a screwdriver, nothing, no crank. So starter is apparently dead. Sounds correct to me since engine start would crank slowly this summer when cold.

Any idea on the hours and cost for a mechanic to buy and replace it (and solenoid)? Can this be done when my boat is on my boat lift?

Oh, just to be complete, found a purple wire from the starboard small stud on starter solenoid (opposite yellow/red wire stud). Seems to be go the coil.

Thanks everyone,

 

[alldodge]

It can be replaced on the lift, and base cost on $100 an hour (can be more or less depending on location) and normally be charged from time tech leaves shop until they return. Starter another $200 so maybe $500

Could replace it your self and safe

The Purple (should be purple/yellow) wires goes to the oil pressure switch and then to the fuel pump. Keeps the pump running once motor starts and oil pressure builds

 

[Scott Danforth]

to R&R a starter yourself, cost of starter and about an hour is under $100

to hire a mechanic to come to your boat and R&R a starter would be about $1000 - $1500 as he will charge you full MSRP on the starter not to mention your time for him starts prior to them leaving the shop and ends after returning.

the purple wire provides full 12 volts to the coil during cranking to aid in starting the motor.

 

[cringe]

Yeah maybe I'll give it a shot myself. How long would it take a decent mechanic to swap starter? I can multiple that time by about 3.

It's held in by just 2 vertical bolts? I can at least try to reach the bolts and see if they turn. From what I've read, the one farthest back by the flywheel housing is a pain to get a socket or wrench on. Might be a show stopper but will see. Is there a gasket? And when installing new one, do I need to worry about aligning to flywheel somehow? I think the 11t gear is retracted in starter body when not in use so probably no. I couldn't find a youtube video. Weight is about 10 pounds so holding new one in place in a tight spot and screwing 1st bolt in should be "fun".

Engine serial 0M092704. Parts are probably Mercury 50-807904A1 starter, 50-863007A1 solenoid. Thanks.

PS: It's a purple wire with yellow stripe.

 

[alldodge]

No alignment or gasket, just remove and install new. Bolts rea tightened to 50 ft lib.
The original starter weight is about 10 lbs, but if you want a better starter with more torque and less weight, get a PM (permanent magnet) type. The PM type are far better then the standard and don't cost that much more.

Suggest in order of preference
API - 10099HD (found it for 150)
​​​​​​Wilison
Delco
ARCO
DB Electric
Sierra

 

[cringe]

I was able to get a 13mm socket on both the starter mount bolts but it's such an awkward position, laying down, reaching back, tight space, can't get any leverage with one arm. Bolts didn't budge. Too bad the bolts aren't on top going down. Then I could stand and do it. Guess I'm calling in the pro.

 

[Jcris]

Don't quit trying. Find a way to get those bolts lose. That much cash just to replace a starter is crazy. You can do this.
There have been many times I've been right where you are and about to give up. Walk away, take a break and try again.
FIND A WAY.
Good luck

 

[Lou C]

There are a couple of tricks to make this job easier.
First if you have trouble getting at it, removing the exhaust manifold on that side can help, I have had the starter out on my boat about 3 times over 15 years but did not have to remove the exhaust.
Second, it takes leverage to get those bolts loose, you will need a long handled ratchet, I used a Craftsman 1/2" drive to get em loose. Next, holding up the starter, I was able to hold it up with one hand and get the bolts started, but another way would require a cooperative helper. Tie a dock line around the body of the starter and have your helper hold it up while you start the bolts. Or if the helper isn't that cooperative, lay a 2x4 long enough across the gunnels and tie it up yourself. I still have an old Delco style one in mine but the next time I have to replace it I'm getting the permanent magnet high torque style starter.

NOTE: make sure you are really loosening the bolts because you are doing it 'upside down' its easy to get confused, you do not want to break those bolts! I take the ratchet and make sure I have it set right, see with your own eyes that its left...loosey….