Boat motor problems

midwestwaterco1

Recruit
Joined
Apr 1, 2023
Messages
4
I have 75hp mercury and when I try to start it. It will crank over 3 or 4 times then stop. I turn over again 3 or 4.times.then stops but it always starts. Got new battery but still same problem. I can put a jump starter on it and it. Turns over as much as I like. Also I hook up DC battery and it turns over great. I bought starter but same problems. Need help
 

QBhoy

Fleet Admiral
Joined
Mar 10, 2016
Messages
8,342
What cca is the battery ? Sounds like it’s not got enough juice. Or maybe your main cables aren’t carrying current as they should or your terminals/posts need cleaned up to help continuity
 

Sweden123

Seaman Apprentice
Joined
Apr 1, 2023
Messages
34
I have 75hp mercury and when I try to start it. It will crank over 3 or 4 times then stop. I turn over again 3 or 4.times.then stops but it always starts. Got new battery but still same problem. I can put a jump starter on it and it. Turns over as much as I like. Also I hook up DC battery and it turns over great. I bought starter but same problems. Need help
in my opinon it sounds not like the battery is the issue here. Your engine always starts am i right? It could be a fuel/ignition related problem.
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
13,446
Are the Clamps that attach to the Battery clean and in good Condition, and can clamp tightly to Clean Posts on the Battery? I am assuming that when you used a Booster, you were attaching it at the Battery. If you were attaching the Booster at the Solenoid or directly to the Starter, then the Cables are suspect
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,854
When you say it stops when cranking, do you mean it stops cranking, but you hear the starter still spinning? If so, the motor fires once, and kicks out the bendix.

Not unusual. Try choking the motor more. So, pump up the primer bulb until hard, cold start lever up, choke button down (or key pushed in), and crank her until she fires, then release choke.
 

midwestwaterco1

Recruit
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Apr 1, 2023
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4
in my opinon it sounds not like the battery is the issue here. Your engine always starts am i right? It could be a fuel/ignition related problem.
Cant be ignition because the problem is it cranks over
When you say it stops when cranking, do you mean it stops cranking, but you hear the starter still spinning? If so, the motor fires once, and kicks out the bendix.

Not unusual. Try choking the motor more. So, pump up the primer bulb until hard, cold start lever up, choke button down (or key pushed in), and crank her until she fires, then release choke.
It stops cranking and I turn off key and then cranks. Then turnoff key. Then cranks. Starter always engages
 

midwestwaterco1

Recruit
Joined
Apr 1, 2023
Messages
4
Are the Clamps that attach to the Battery clean and in good Condition, and can clamp tightly to Clean Posts on the Battery? I am assuming that when you used a Booster, you were attaching it at the Battery. If you were attaching the Booster at the Solenoid or directly to the Starter, then the Cables are suspect
I will clean cable
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
37,835
Is this a 3 or 4 cylinder motor ?--Serial # is ?---Ignition problem I say.----I can not see , hear or feel your motor.---Answer this.----Do you have consistent spark that jumps a gap of 3/8" or more on all leads.---Yes or no ?----And the spark plugs are not involved in this simple test.
 

QBhoy

Fleet Admiral
Joined
Mar 10, 2016
Messages
8,342
I have 75hp mercury and when I try to start it. It will crank over 3 or 4 times then stop. I turn over again 3 or 4.times.then stops but it always starts. Got new battery but still same problem. I can put a jump starter on it and it. Turns over as much as I like. Also I hook up DC battery and it turns over great. I bought starter but same problems. Need help
What do you mean when you say when you hook up a dc battery it always starts ?
 

QBhoy

Fleet Admiral
Joined
Mar 10, 2016
Messages
8,342
Check the main fuse too. Could be only just holding on. What engine are we talking here ? Early 2 stroke 4 cylinder, later 2 stroke 3 cylinder or newer 4 stroke 4 cylinder and onward
 
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