2003 Mercury Mercruiser 3.0 - how to replace starter solenoid

[Glockster]

I am having issues with her boat (not my dang boat, I just have to fix it when it don't work), it has a 2003 Mercury Mercruiser 3.0

It ran fine for a few weeks then this past weekend it wouldn't start - just a click from engine compartment.

I had battery checked as it is a few years old but I do keep it on a float charger in a warm garage during winter months - the boat is winterized and kept in a unheated garage. Both places I took battery to said the battery was showing 125 CCA and it should have been 600. Purchased a new battery and still had the click.

I then removed the wires, one at a time, and scraped/polished the ends and all their connections. After re-connecting them all I still had the click.

I then broke down and called a boat mechanic who talked me thru it. Determined the starter starts using the jumper cable so it is the solenoid.

On the MerCruiser 3.0 (2003 version) it is attached to a metal plate/bracket which is attached to the block. I thought I could just remove the solenoid with the two bolts but they have nuts on the back which is between the large plate/bracket and the block, just about impossible to get to the nuts.

I then thought I would be able to remove the large plate/bracket but it is attached to the engine block with a couple 'weird' screws/bolts. They look like the opposite of a 12 pt hex screw. I wouldn't know where to get a socket like that.

And the mechanic said it is a real pain to get it all lined up again and get the screws started when attaching it back..... and he doesn't make house calls, so I'd have to get it started, remove it from the lake, tow it about 50 minutes to boat shop, leave it there and pick up later. (I know the mechanic and quite a few friends know/use him and he is a good guy)

Has anybody removed the weird screws and the large bracket (with special socket) and been able to re-install it with out too much trouble.??

 

[fishrdan]

Yeah, that's a pain of a repair, just to replace the slave solenoid. The 12 point bolts you are referring to should fit a "12 point socket"

I had 2 of those cheap solenoids go bad on my 3.0L, and seeing what a PITA of a repair it is, the last time I used a bigger solenoid off V8. It's a much heavier duty solenoid and I haven't had a lick of problems with it in 4-5 years. Drilled a couple new holes and the wiring fit, though I did have to ream the big wire lugs a tad as the solenoid studs were a bit bigger. Something like this...

 

[Bt Doctur]

just so much easier to remove the whole starter and do it on the bench or take it to a shop.

 

[Glockster]

the solenoid is attached to a bracket near the top of the block, not attached to the starter. I had the starter out a few years ago and that was a pain but doable, this looks beyond me....

 

[muc]

Yes it's a pain to replace this slave solenoid. But are you sure it's bad? When you jump the two large terminals to each other does it crank, than when you jump the large terminal with the red wire connected to it to the small terminal with the yellow with red tracer connected to it does it crank? If not you have other problems.

 

[Bt Doctur]

the solenoid is attached to a bracket near the top of the block, not attached to the starter. I had the starter out a few years ago and that was a pain but doable, this looks beyond me....

better read the manual.There are 2 solenoids in most boats, a slave and a starter solenoid. starter solenoid is mounted to the starter and a slave can be anywhere on the motor

 

[truckstop]

I am having issues with her boat (not my dang boat, I just have to fix it when it don't work), it has a 2003 Mercury Mercruiser 3.0

It ran fine for a few weeks then this past weekend it wouldn't start - just a click from engine compartment.

I had battery checked as it is a few years old but I do keep it on a float charger in a warm garage during winter months - the boat is winterized and kept in a unheated garage. Both places I took battery to said the battery was showing 125 CCA and it should have been 600. Purchased a new battery and still had the click.

I then removed the wires, one at a time, and scraped/polished the ends and all their connections. After re-connecting them all I still had the click.

I then broke down and called a boat mechanic who talked me thru it. Determined the starter starts using the jumper cable so it is the solenoid.

On the MerCruiser 3.0 (2003 version) it is attached to a metal plate/bracket which is attached to the block. I thought I could just remove the solenoid with the two bolts but they have nuts on the back which is between the large plate/bracket and the block, just about impossible to get to the nuts.

I then thought I would be able to remove the large plate/bracket but it is attached to the engine block with a couple 'weird' screws/bolts. They look like the opposite of a 12 pt hex screw. I wouldn't know where to get a socket like that.

And the mechanic said it is a real pain to get it all lined up again and get the screws started when attaching it back..... and he doesn't make house calls, so I'd have to get it started, remove it from the lake, tow it about 50 minutes to boat shop, leave it there and pick up later. (I know the mechanic and quite a few friends know/use him and he is a good guy)

Has anybody removed the weird screws and the large bracket (with special socket) and been able to re-install it with out too much trouble.??

I realize this is now an ancient thread but curious as to whether or not you ever attempted this. I ran into the same problem and ended up bending the metal tabs that hold the solenoid to its base back, pulling it off, putting in the new one and bending the tabs back again. But I didn't love doing it that way. Curious if you ever removed that plate or found a better solution! Thanks!

 

[jbcurt00]

I realize this is now an ancient thread

Refrain from posting to old inactive topics