older carburetated mercruiser 5.7 hard start

brian3127

Chief Petty Officer
Joined
Jun 10, 2007
Messages
509
Rochester quadrajet carb.
How many pumps do you give your engine at the throttle to get it started.
I put a spark tester on the engine and the spark wasn't very good so I took the cap off and this is what I found. I ordered a new pickup. I cant get a serial number off the engine it is very tight in the engine compartment.
 

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kenny nunez

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Jun 20, 2017
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With a volt meter on the + side of the coil crank the engine over. You should read 11-12 volts. If it is much lower then the “by pass” circuit from the outer connector on the starter solenoid is the problem.
To further prove out the problem run a jumper wire directly from the + battery to the + side of the coil. If the engine starts easier then the fault is the starter solenoid.
 

brian3127

Chief Petty Officer
Joined
Jun 10, 2007
Messages
509
With a volt meter on the + side of the coil crank the engine over. You should read 11-12 volts. If it is much lower then the “by pass” circuit from the outer connector on the starter solenoid is the problem.
To further prove out the problem run a jumper wire directly from the + battery to the + side of the coil. If the engine starts easier then the fault is the starter solenoid.
having trouble understanding, what the starter solenoid has to do with the hard starting. then engine turns over just fine
 

kenny nunez

Captain
Joined
Jun 20, 2017
Messages
3,355
When the key is turned and the starter is engaged there is no or very little voltage at the + side of the coil provided from the ignition switch, that is the purpose of the ”by pass” circuit on the starter solenoid to provide voltage at the coil.
Just check the coil to make sure there is 12 volts provided in cranking mode.
 
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