Engine don't start

[windstalkers]

Hi . I have 2 new batterys 100ah each one full charge I never discharge under 75% . Everytime I want to star my engine is like no power . Went I Crank to star my started drop from 13.7to 9 and batteries too . Any help why this is happen. I have 0 experience in electric please don't be too technical to explain.

Thanks Enrique

[jkishel]

First thing to do is check and clean all battery cable connections, especially the ground (black cable) connection to the engine block. If problem persists, let us know and we can move on from there.

[Tupaia]

Could also be the isolation switch, the carbon terminals degrade and will work ok for light loads the resistance is too high on cranking loads.

[dksail]

It sounds like both batteries are in parallel to start your engine? You might want to isolate each battery and try to start the battery with each. It may be that one batteries is bad.

[sailorboy1]

when either of my boats did this it was: 1 - bad wire in the wiring harness rom the engine panel to the engine, 2 - bad wire on the start relay at the engine

you can check for a starter wiring related issue by trying to start the engine by direct jumpering on the starter

[skipperpete]

Originally Posted by windstalkers

Hi . I have 2 new batterys 100ah each one full charge I never discharge under 75% . Everytime I want to star my engine is like no power . Went I Crank to star my started drop from 13.7to 9 and batteries too . Any help why this is happen. I have 0 experience in electric please don't be too technical to explain.



Thanks Enrique

By “don’t start” do you mean fails to rotate? Rotates too slowly or rotates but does not fire up? Each situation requires a different action.
First up, turn the engine over manually with the de compressors open and see if there are any tight sectors. If its free and easy to rotate, try it with the keystart and if it spins up, drop the de compression levers.... it should start but if rotation slows dramatically, start looking for a bad earth or corroded terminals.
I assume this is the 3GM that you installed after the 2QM transplant
Pete

[windstalkers]

Originally Posted by skipperpete

By “don’t start” do you mean fails to rotate? Rotates too slowly or rotates but does not fire up? Each situation requires a different action.
First up, turn the engine over manually with the de compressors open and see if there are any tight sectors. If its free and easy to rotate, try it with the keystart and if it spins up, drop the de compression levers.... it should start but if rotation slows dramatically, start looking for a bad earth or corroded terminals.
I assume this is the 3GM that you installed after the 2QM transplant
Pete

Yes pete, 3gm , went I pull the 3 ( compressor?) Back for each cylinder, the motor rotate but don't star ,but if I connect and extra charger with booster then the motor start.
Thanks

[skipperpete]

Originally Posted by windstalkers

Yes pete, 3gm , went I pull the 3 ( compressor?) Back for each cylinder, the motor rotate but don't star ,but if I connect and extra charger with booster then the motor start.

Thanks

Do you have a battery master switch or a shunt between the battery and the starter solenoid? Either of these could cause problems due to arcing or corrosion.
And another cause of the clacking behavior could be insufficient power in the solenoid wire......the thin one from the keyswitch to the spade terminal on the starter solenoid. Sometimes this causes the “Catch and release” sound that you describe.
Pete.

[JimsCAL]

Originally Posted by windstalkers

Yes pete, 3gm , went I pull the 3 ( compressor?) Back for each cylinder, the motor rotate but don't star ,but if I connect and extra charger with booster then the motor start.
Thanks

Sounds like you are pulling the decompression release levers on each cylinder. That would reduce the load on the starter and allow the engine to spin, but it won't start without compression. One emergency technique to get an engine going with low batteries is the get it spinning with the compression releases engaged and then close them one by one to start the engine.

Then it sounds like you connect you connect a battery charger and the engine will start. I assume it won't start without the charger. That would indicate weak batteries. Either low on charge or needing replacement.

[jkishel]

Again, check and clean the battery cable connections. It costs nothing and eliminates the most likely cause!

[windstalkers]

If I try with the key from the outside panel harness, sound like is not enough juice, Tac tac tac . The motor don't rotate.
Thanks Enrique

[sailorboy1]

Originally Posted by windstalkers

If I try with the key from the outside panel harness, sound like is not enough juice, Tac tac tac . The motor don't rotate.
Thanks Enrique

there is a corrosion/wire problem in the starter circuit!

[chris95040]

When you measure the “battery voltage” while starting, make sure you are attached to the studs on the battery itself, not any of the wire’s connectors.

If you observe 9V *on the battery* while starting, that would indicate the battery is undersized or the starter is failing.

If the actual voltage, measured directly on the battery while starting, is 12V, whereas downstream at the starter it measures 9V, that indicates a wiring/corrosion problem.

[smac999]

Originally Posted by windstalkers

Went I Crank to star my started drop from 13.7to 9 and batteries too .

Thanks Enrique

if the battery is dropping to 9v ether the battery is weak / low / too small or you have an issue with the starter or motor (seized ect) causing excess current.