Bone Head Mistake - SB Engine wont start

[gnealon]

Happy Easter everyone!

As embarrassing as this is to admit, i forgot to check the orientation of the terminals on my battery and put my SB engine battery in backwards. Now the damn thing wont start :smt013

I do NOT have any voltage at the 50 AMP breaker on the engine. I checked all the breaker panels (ER, HELM, Battery Switch compartment) and nothing was tripped. Also... i pulled the main DC breaker panel next to battery switches and all the breaker have voltage :-/

I'm completely at a loss here. I can't seem to figure out where that 50 AMP breaker on the engine is fed from. I have a feeling that my batter charger is not working either. When i switch from ON to OFF i do not have a fluctuation in voltage at all. not even a tenth of a volt. Not sure if a blown charger could effect this or not.

Also... I feared maybe i hurt the ECM, so i switched ECM's and my port engine started fine on the SB ECM. I also switch battery's in case the battery was bad.

Guys - any ideas? Much appreciated. I want to kick my own a$$ right now!

 

[Lazy Daze]

My first thought would be the 90amp fuse that's attached to the starter solenoid. I think it's about a $25 part. Getting to it, though, is usually not fun.

If I'm not mistaken, battery voltage goes through this fuse before that 50amp "red button" circuit breaker.

 

[gnealon]

My first thought would be the 90amp fuse that's attached to the starter solenoid. I think it's about a $25 part. Getting to it, though, is usually not fun.

If I'm not mistaken, battery voltage goes through this fuse before that 50amp "red button" circuit breaker.

Ahh... is this fuse inline close to the starter solenoid? When i try to start the engine, i do hear a click (i assumed starter solenoid activating).

 

[Lazy Daze]

Actually it's right on the starter-mounted solenoid - it's a little whitish/yellowish plastic square.

I just checked the wiring diagram for my engine (it should be in the Mercruiser manual that you might have - at least for me, it came with the all of the other owner's pack stuff)...

Coming off the other side of the fuse is an orange wire that goes to the alternator and a red wire goes to that 50 amp push button breaker. There is also a Yel/Red wire that goes to the starter slave solenoid (although this wire is not hooked directly to the 90amp fuse.

Hope that helps! And let's both hope that's all it is!

 

[gnealon]

Actually it's right on the starter-mounted solenoid - it's a little whitish/yellowish plastic square.

I just checked the wiring diagram for my engine (it should be in the Mercruiser manual that you might have - at least for me, it came with the all of the other owner's pack stuff)...

Coming off the other side of the fuse is an orange wire that goes to the alternator and a red wire goes to that 50 amp push button breaker. There is also a Yel/Red wire that goes to the starter slave solenoid (although this wire is not hooked directly to the 90amp fuse.

Hope that helps! And let's both hope that's all it is!

haha... I am praying that i didn't do any other damage. I am afraid i did.

1. When i put the SB ignition to "On" i get 2 beeps and my MPH guage goes to 25 MPH.

2. I didn't get any reading for water PSI on my port engine when it running. Normally I get around .8 PSI when on muffs at idle. :-( Can putting the battery on backwards kill sensors as well?

3. Blew a fuel relay... replaced already.

4. My battery charger red light is solid...green flashing fast. But it shows 0 AMps on the charger mounted guage?!?!? Not sure if that is normal.

btw.. I see that white square you are referring to. THANK YOU. I am going to give that a shot. I am barely able to reach it. Does it just pull out? It will mostly be by feel.

Thank you for all this help btw. Much appreciated.

 

[Lazy Daze]

Hopefully I responded back to you before you do too much contortionism:smt101

Before you pull the fuse (which IIRC is held on with either a single stud or a nut... I think nut) check your voltage going into it (center) and going out of it. That will tell you if the fuse is good. Remember, to have the appropriate battery switch ON. You do not need the key on for this.

This still may not be your problem, but since you don't have power at the 50amp breaker, this is a good place to start.

 

[gnealon]

Hopefully I responded back to you before you do too much contortionism:smt101

Before you pull the fuse (which IIRC is held on with either a single stud or a nut... I think nut) check your voltage going into it (center) and going out of it. That will tell you if the fuse is good. Remember, to have the appropriate battery switch ON. You do not need the key on for this.

This still may not be your problem, but since you don't have power at the 50amp breaker, this is a good place to start.

Thank you! Actually as I am laying across both engines my phone goes off (it was an email notification that you responded ). So before i went any further i checked the fuse and indeed it was BAD. I finally got it out. My back is killing me. I'm praying that this fixes the issue. So mad at myself right now.

Thanks for all the help so far. Once i get the new fuse and put it in, i'll report back.

 

[gnealon]

The good news is regarding your charger, each line has a inline fuse within the charger, if you open the panel you will see it. (I'm assuming you have the standard charger that SR puts in their boats) They are very easy to replace, in fact, you probably have a spare in that same compartment, assuming you haven't blown and replaced one yet. The fact that your charger is still powered is a good sign that you didn't goof it up.

As for the other systems...well, I wish you the best.

Awesome! I did not know that Thank you!

 

[Lazy Daze]

Thank you! Actually as I am laying across both engines my phone goes off (it was an email notification that you responded ). So before i went any further i checked the fuse and indeed it was BAD. I finally got it out. My back is killing me. I'm praying that this fixes the issue. So mad at myself right now.

Thanks for all the help so far. Once i get the new fuse and put it in, i'll report back.

My fingers are crossed for 'ya!

 

[gnealon]

So Guys... I'm happy to report back all good news. The 90 AMP fuse did the trick (THANK YOU LAZY). I had a blown water pressure sensor (all fixed and reading fine). And I also had a blown 30 AMP fuse in the battery charger (THANK YOU SCOTT).

I just replaced both distributor caps... roters... and water pump impellars. I can't begin to describe how hard the impellars were on the Bravos. I have twin 5.0's, the damn thing was sooo close to the stringer (Port) and hull (SB) that i had to remove the hanger bracket in place. Ugh. Anyways, first time doing it and man, REAL PIA.

Few more maintenance items to go w/ a estimates splash day of this Saturday! Thanks again for all the help!

 

[Lazy Daze]

Yes, great news! Glad to hear that's all it was. Phew! I can uncross my fingers now... it's been really tough to write the last few days!:smt001

 

[gnealon]

Yes, great news! Glad to hear that's all it was. Phew! I can uncross my fingers now... it's been really tough to write the last few days!:smt001

:lol: Thx for keeping them crossing for a week! I needed all the luck i could get :grin: