Mercruiser 4.3 will not start ( no clicks, not even cranking)

[vasi1]

Hello everyone, i am still new to boats and trying to understand them. I have a 2010 Tahoe 5QI, about 150 hours usage, that i have been using for the last 3 years ( not a lot, 4-5 times a year). Never gave me problem till now, when i notice the starting battery was dead ( even thou was only 5 months old- no clue what happened). I bought a new battery and when i tried to start the engine nothing happened.
It is a mercruiser MCM 4.3 litre. No cracking attempts, no clicking nothing, just the oil pressure alarm.
Here is what i have done: change both batteries ( one is for trolling), checked all the fuses under the dash and on the engine ( it may be 25 or so) , all good; killer switch in "run" position, the gear in neutral. I have power to radio, lights, bilge pump, blower, trim, gas gauge. The power also is going to starter ( according to me voltmeter). i was thinking it may be the starter or the solenoid but i would thing that if that is the case then i would have a click, a noise, some indication that the engine is trying, but i have nothing.
So i am out of ideas, not knowing what to do next.
Any suggestions would be greatly appreciated!
Thank you !

 

[badrano]

What do you mean by "power is going to the starter"?

It could be a couple of things....the ignition switch itself, neutral safety switch on the throttle, or, if you have it, the starter relay on the engine. I would do a voltage check and see if there is voltage on the ignition switch when you turn it to START as well as a voltage check on the neutral switch on the throttle. In both locations, it would be the yellow/red wire. If they check out ok, follow the wire in to the engine bay. Some engines differ on where the starter line terminates. It may go directly to the starter or it may go through another relay that is mounted on the top side of the engine or zip tied to the engine harness. My 204 had the relay zip tied to the engine harness and for some reason the yellow/red was yellow/black coming in to the relay, but yellow/red from the relay to the starter.

 

[vasi1]

Thank you for the reply. Regarding the starter I meant that there is a red wire going into it and that reads 12 v or so.

I did check the ignition.i get 10.9 volts when I turn it to start.
A new development.i muted the oil pressure alarm and now I can hear a faint click on the top of the motor... (img), i am not sure which part...

 

[badrano]

10.9 volts is not good. You've got a bad connection somewhere.
The clicking sound may then be that starter relay. I had a 5.0 TKS and the relay was in the area of what your picture shows. It should look something like this (at least it was on my engine).


The contact side of the relay is fused and I believe the fuse is another connector looking thing dangling off the harness somewhere. If that fuse is blown, the start solenoid won't activate.

 

[vasi1]

10.9 volts is not good. You've got a bad connection somewhere.
The clicking sound may then be that starter relay. I had a 5.0 TKS and the relay was in the area of what your picture shows. It should look something like this (at least it was on my engine).
View attachment 336651

The contact side of the relay is fused and I believe the fuse is another connector looking thing dangling off the harness somewhere. If that fuse is blown, the start solenoid won't ac

 

[vasi1]

The bad connection it is troubling because i did not find any bad ones. The battery connections are as in the picture from the first post. I have to mention that i get 10.9 reading on the ignition even when i am not turning the key to start position..will this relay (or whatever it is) may have something to do with this? ( img)
thank you

 

[vasi1]

The bad connection it is troubling because i did not find any bad ones. The battery connections are as in the picture from the first post. I have to mention that i get 10.9 reading on the ignition even when i am not turning the key to start position..will this relay (or whatever it is) may have something to do with this? ( img)
thank you

i just google the part that is in the picture and is a circuit breaker...not sure it has anything to do with all issue

 

[vasi1]

so it seems that this circuit breaker trips every time i try to start the engine. So i wonder if the circuit breaker is faulty or something else. Testing the circuit breaker i get " open line " when i press the red button and 0.05 ohm when i press the yellow button.

 

[badrano]

That circuit breaker is the main breaker for all the engine stuff....it feeds the ignition switch. The rest of the boat should have another main circuit breaker (house circuit).
Where are you measuring the 10.9 volts? If it's tripping, you've got a short some where in the start circuit.

 

[vasi1]

That circuit breaker is the main breaker for all the engine stuff....it feeds the ignition switch. The rest of the boat should have another main circuit breaker (house circuit).
Where are you measuring the 10.9 volts? If it's tripping, you've got a short some where in the start circuit.

i measure 10.9 v on the ignition swich ( there are tree connectors in that ignition switch. Two of them read 10.9 and the third one 0 when is not activated; when i try to start the engine the third connecto,r which has double wire on it, reads also 10.9)

 

[badrano]

so it seems that this circuit breaker trips every time i try to start the engine. So i wonder if the circuit breaker is faulty or something else. Testing the circuit breaker i get " open line " when i press the red button and 0.05 ohm when i press the yellow button

What is the voltage reading on the terminals of the breaker?
The feed to the breaker comes from the terminal on the starter that is connected to the battery (large gauge wire).
If I understand what you've said, you're reading 12v on the starter terminal that's connected to the battery.

 

[vasi1]

What is the voltage reading on the terminals of the breaker?
The feed to the breaker comes from the terminal on the starter that is connected to the battery (large gauge wire).
If I understand what you've said, you're reading 12v on the starter terminal that's connected to the battery.

Both terminals read 13.1 V when i am not starting it. When i try to start the breaker trips ( i hear a click) and one of the connectors reads 13.1 ( probably the one connected to battery) the other 11.4 ...of course the motor does not start

 

[vasi1]

Both terminals read 13.1 V when i am not starting it. When i try to start the breaker trips ( i hear a click) and one of the connectors reads 13.1 ( probably the one connected to battery) the other 11.4 ...of course the motor does not start

i wonder if i should try to bypass the breaker for a secunde to see if the engine will start

 

[GA_Boater]

i wonder if i should try to bypass the breaker for a secunde to see if the engine will start

You might let the smoke out of what is causing the breaker to pop. It would be better to disconnect the loads that the breaker feeds until it stops popping.

A word of caution - Repeated popping of a circuit breaker weakens it and causes it to pop at less than the amperage rating until it won't reset.

 

[vasi1]

You might let the smoke out of what is causing the breaker to pop. It would be better to disconnect the loads that the breaker feeds until it stops popping.

A word of caution - Repeated popping of a circuit breaker weakens it and causes it to pop at less than the amperage rating until it won't reset.

Thank you GA_Boater
i did disconnect the loads, and of course nothing happens, it appears that that breaker controls the motor starting process...
i was not successful in finding what causes the breaker to trip...l

 

[badrano]

Thank you GA_Boater
i did disconnect the loads, and of course nothing happens, it appears that that breaker controls the motor starting process...
i was not successful in finding what causes the breaker to trip...l

Was the breaker still tripping?
This may be a wild idea, try disconnecting the starter wire (should be yellow/red) from the ignition switch. If the breaker still trips when you turn the switch to start, you may have a bad ignition switch.

 

[GA_Boater]

Thank you GA_Boater
i did disconnect the loads, and of course nothing happens, it appears that that breaker controls the motor starting process...
i was not successful in finding what causes the breaker to trip...l

Did the breaker pop with the loads disconnected?

 

[nola mike]

Thank you GA_Boater
i did disconnect the loads, and of course nothing happens, it appears that that breaker controls the motor starting process...
i was not successful in finding what causes the breaker to trip...l

If it doesn't trip when the ignition is on, that means that the fault is from the starting circuit, so either you're shorting to ground when you energize the circuit, or your starter is drawing too much current. You just need to work your way back. Try disconnecting the yellow/red white from the slave solenoid and try again. If it doesn't trip, that means your working is good until that point. Next disconnect yellow/red at the starter. That will eliminate the wiring until that point. After that depends on your wiring

 

[vasi1]

Thank you for all your helped. Greately apperciated.
It turned out to be the starter .
The starter for the motor (86300TA1) fluctuate widely from $60 to $220.
hard to tell if there is a connection between quality and price. Any advice on where should i buy one from and whether the price should be a factor?

 

[nola mike]

For me, how much I spend on a part is directly proportional to how big of a PITA it is to replace said part...
Either way to with a PMGR starter. I've had a couple of DB electrical starters that haven't crapped out after a few years of use, others have used them as well