Mercruiser 3.0 TKI engine crank half time - never starts

[Jonatande]

1. When I engage the key to 'run', audio warning beeps (Normally) but as soon as I turn to 'start' the engine cranks or more like "clonks" maybe once or even half and never starts.

2. When I retry - not even the audio warning beep will activate and no crank at all. Completly dead

3. Waiting 12 hours - same thing to 1. happens (half crank) and repeat with 2.

Only engine seemed to be cut from power, accessories' work fine.

Some other symptoms:
1. Checked battery voltage on my two batteries and they are 12.44,12.64 respectively.
2. Circuit breaker 50 amp is not tripped
3.. When I run the boat for 4 weeks ago - the engine suddenly died when activating the trim plan and could not restart (towed in)
4. Engine would start day after and had no problems starting and running it on idle for a couple of times.
5. I have a BOAT GARD?

Things I checked:
1. Neutral position of throttle in engine room. Unclear if looks good? -> See picture.
2. Engine oil, coolant etc.







I posted in other forum but now I have better symptoms to provide - I am completely new to boats so not only is it diffult to deal with failures but also if there is something in process I am doing wrong.

 

[alldodge]

Checked battery voltage on my two batteries and they are 12.44,12.64 respectively.

12.64 is good, but the 12.44 is 80% that is if your meter is accurate

Connect meter to the starter post and try to start. Let us know what you find

 

[Jonatande]

12.64 is good, but the 12.44 is 80% that is if your meter is accurate

Connect meter to the starter post and try to start. Let us know what you find

Yes will do tonight - I will update to see if voltage drop at starter

 

[nola mike]

Sounds like an issue with your batteries or connections. Connections especially given your breakdown. Engine doesn't require much power once running. Don't see a pic posted. Neither I nor Google knows what a boat gard is.

 

[Jonatande]

Sounds like an issue with your batteries or connections. Connections especially given your breakdown. Engine doesn't require much power once running. Don't see a pic posted. Neither I nor Google knows what a boat gard is.

Yea, checked connections at start motor and battery but looka fine. But I could actually try to disengage the m-acr and isolate on battery ti use the same for both start motor and accessories.

Only thing is that is wired strangely with the m-acr.

 

[alldodge]

Can look good but be corroded under connections
The ACR is not the issue
Those auto type connections should not be used. Connect the cables direct to the studs next to them and use nuts

Did you get a meter reading?

 

[briangcc]

Is that your starter in the 2nd pic? Cause if it is, its got a bunch of rust colored water/fluid running down it. I'm wondering if....1. Your starter is seized or 2. You have a frozen block.

Where are you located? Area where it freezes? Was the boat properly winterized before the temps dipped?

 

[Jonatande]

Can look good but be corroded under connections
The ACR is not the issue
Those auto type connections should not be used. Connect the cables direct to the studs next to them and use nuts

Did you get a meter reading?

This is how it’s all connected. Bottom of picture I cant see because it goes between engine compartment.

Only tried meter reading on batteries and they showed 12,4 and 12.64. When I do circuit tracing - do I need to worry about which battery ground pool I connect the mentimeter to when testing with an appliance?

Not sure what you mean about the connections direct to studs. But nuts you mean these https://www.amazon.com/wire-nuts/s?k=wire+nuts

 

[Jonatande]

Is that your starter in the 2nd pic? Cause if it is, its got a bunch of rust colored water/fluid running down it. I'm wondering if....1. Your starter is seized or 2. You have a frozen block.

Where are you located? Area where it freezes? Was the boat properly winterized before the temps dipped?

I live in Sweden but not sure it was proper winterized. However its closed cooling system.

But what you see is a weird picture due to sunlight and it’s actually oil but it doesnt appear to leak.

 

[Jonatande]

This is in right position as well right?

 

[alldodge]

I want to know if the voltage drops at the starter while the motor is cranking. If it drops below 10V the starter does not have enough to turn the motor over.

Doing the same test at the Bat will help but need to know at the starter

The ACR should connect both Positive terminals on each Bat together. The below is how it should be wired.

 

[Bondo]

Ayuh,..... Those battery connections look like crap,.....
Take 'em apart, 'n clean 'em to shiny metal Clean,...

Yer problem sounds like a corroded Ground connection,.....
So clean both ends of all the cables,....

 

[Jonatande]

12.64 is good, but the 12.44 is 80% that is if your meter is accurate

Connect meter to the starter post and try to start. Let us know what you find

An update for today:

1. I simply switched the places of the two batteries - I put the better 12.64v on starter and put the bad 12.44v on right side (house). Engine started! My conclusion is that 12.44 simply wasnt enough to start the engine and it was a bad battery.
2. Remember I told that I had an engine break down as well when I used the trim planes. Well it turns out - the trim plane and starter motor were both connected to the bad 12.44 starter battery which bybasses the M-ACR.

Still unsure about if it is M-ACR wiring, voltage drop somewhere or only bad battery that is my fundamental problem:

• M-ACR: I noticed that when I had the engine running - the "now good" starter battery did not charge nor draw any eletricity. It was constant on 12.60. No "combined charging" light indicating charging was present on M-ACR
• BAD BATTERY: The house battery (now bad battery) got charged and noticed a voltage of 14.50 but as the engine was idling the voltage dropped constantly and after 20 minutes or so it was 14.36.
• VOLTAGE DROP IN CIRCUIT AND BAD BATTERY: I still would have think 12.44 on bad battery would be sufficient to start the engine. Thus could the failure of the bad battery to start the engine be a combination of voltage drop somewhere to starter.

 

[alldodge]

All ACR's will not connect a good Bat to a Bad one. It knows if voltage falls below a preset point it will disconnect and not allow it to drain the good Bat. For the sounds of it, the house Bat was being charged by the Alternator when motor was running, but the ACR kept the start Bat from doing so

That said, the ACR will only change both Bats IF the Positive post are connected between the ACR as in my Pic above

 

[Jonatande]

All ACR's will not connect a good Bat to a Bad one. It knows if voltage falls below a preset point it will disconnect and not allow it to drain the good Bat. For the sounds of it, the house Bat was being charged by the Alternator when motor was running, but the ACR kept the start Bat from doing so

That said, the ACR will only change both Bats IF the Positive post are connected between the ACR as in my Pic above

That makes sense. Because I have seen the ACR charge both before. That was before I ran into the starting problems for 3 weeks ago.

But in this case it doesnt make sense. Because it was the now "good" starting battery with higher idle voltage that didn't get charged and the "bad" house battery that got charged, altough with voltage constantly dropping.

 

[alldodge]

The exception to both not getting charged.
If the ALT supplies power to a bad Bat, then the ACR will charge neither because it doesn't connect a Bad to a good one.

In your case the ALT is connected to the Start Bat which was bad and ACR would not connect to good house. Put good house in start position so ALT will charge now start Bat, but will not connect to house side because old start Bat is bad

To restate last point, if the ACR is not wired as I show then all best are off. Your wiring does not show its the same

 

[Jonatande]

The exception to both not getting charged.
If the ALT supplies power to a bad Bat, then the ACR will charge neither because it doesn't connect a Bad to a good one.

In your case the ALT is connected to the Start Bat which was bad and ACR would not connect to good house. Put good house in start position so ALT will charge now start Bat, but will not connect to house side because old start Bat is bad

To restate last point, if the ACR is not wired as I show then all best are off. Your wiring does not show its the same

I would like to survive the summer and replace with proper battery switch until the end of summer. I have updated the wire diagram as I done some more digging. What puzzles me now is if the "house battery" power shortage could impact power to engine being loss? After all, House battery is not charging, but the loss of house battery power from activating the trim planes caused the engine today and possible not to start. (See updated diagram)

 

[alldodge]

That's a messy wiring diagram. The ACR is not connected directly to the Bats, but shows it does connect to each and thru switch. The ACR should be direct connect without switches.

The trim should be connected to the start Bat

With the house Bat not being charged thru the ACR while motor is running means the ACR is bad, the fuse has blown or the House Bat is bad (Just listing the 3 possibilities of why)

 

[Jonatande]

That's a messy wiring diagram. The ACR is not connected directly to the Bats, but shows it does connect to each and thru switch. The ACR should be direct connect without switches.

The trim should be connected to the start Bat

With the house Bat not being charged thru the ACR while motor is running means the ACR is bad, the fuse has blown or the House Bat is bad (Just listing the 3 possibilities of why)

First and foremost, Thanks a lot alldodge. Couldn't be more thankful.
I have reposition the ACR to come closer to battery - at least on "IN" on the switches.

I checked for fuses and work fine with continuity test. I did however notice that there was no continuity on ACR Device between negative lead to negative batteries and lead to positive battery. Thus ACR is closed or is not sending leads thru.

But ACR should work - After all, as long as one battery is good and charge over 13.7 - then ACR should open up and try to charge second battery even if it's bad.

Enjoy your weekend! Hopefully in a boat

 

[Scott Danforth]

Yea, checked connections at start motor and battery but looka fine.

Look again. That Walmart battery adapter should be thrown away. The batter cable ends sanded with 320 grit, and bolted to the threaded studs that also need to be sanded