76 Mercury 1150 Odd Starting, and starting battery vs deep cycle

[kungpaoshizi]

I'm trying to trouble shoot why this motor isn't starting right away "like a car"?
I'm not too familiar with powered boats, but I saw an article of "using deep cycle vs starting battery" and the need for it because of the initial larger amps needed..

I think the guy put a deep cycle in there, because when I goto start it from cold, it acts like the battery or starter is dead/dying. Sometimes I'll hit the ignition button, and nothing, then I'll hit it again, or over and over and over (meanwhile no noise from the starter cranking) then I'll get a little RRRrr from the starter, then none, then some, then it'll kick off and start.

Ideas?

Thanks very much!

 

[merc850]

Re: 76 Mercury 1150 Odd Starting, and starting battery vs deep cycle

A regular cycle marine starting battery is all that's needed, use a voltmeter to check the battery voltage while cranking engine - it should read + 12v.

 

[Texasmark]

Re: 76 Mercury 1150 Odd Starting, and starting battery vs deep cycle

I had a well used deep cycle battery as the only cranking battery for a 360 cubic inch John Deere diesel tractor and it had no problems. That is much more amperage than you engine requires. Deep cycles will start your engine.

If you have low voltage at your starter terminals you will have poor performance in trying to start. Low voltage at the starter terminals can be caused by:

Dirty connections anywhere between the battery hot and cold terminals and the starter terminals and I'm talking about on the metal to metal contact side (inside), not the outside which cleaning accomplishes nothing electrically but looks nice. Bad cables where the crimp terminal to the copper wire is corroded is a dirty terminal;

worn contacts in the solenoid, not having a large enough contact area due to pitting from age;

high internal resistance in the battery (old sulfated battery);

specific gravity of electrolyte in battery (charge level).

A full battery is about 12.7 volts. The starter needs about 10 or so to function. It takes 150 or so amperes to roll the starter adequately. With only 2.7v/150 amps, you don't have a lot of ohms (resistance) you can have in the circuit. I just told you how to check for and get rid of most of them.

Mark

 

[Chris1956]

Re: 76 Mercury 1150 Odd Starting, and starting battery vs deep cycle

I would inspect the starter cables from the battery. Look for bulges in the insulation. That will indicate corrosion. Clean all ends of the cables. As long as the battery is good, it should crank very well. You need to hold the choke button down (cold start lever up) when cold starting.

 

[kungpaoshizi]

Re: 76 Mercury 1150 Odd Starting, and starting battery vs deep cycle

I wonder if the battery just got old then.. I hit the choke button, and the voltage on the gauge dropped to 10 (which is as far as it goes)

 

[Texasmark]

Re: 76 Mercury 1150 Odd Starting, and starting battery vs deep cycle

I wonder if the battery just got old then.. I hit the choke button, and the voltage on the gauge dropped to 10 (which is as far as it goes)

Say that again. Are you telling us that your choke current only, not trying to start, pulled the battery voltage down that far? If so, yes you have a problem. Discharged battery, sulfated battery not allowing battery to charge properly.....some cells don't take on a charge making the output voltage low.....current as low as your choke could show up as a low voltage battery as may be your case.

Where is the voltmeter wired into the circuit? If your answer to the above question is yes then it doesn't matter where the voltmeter is wired. Your battery is bad/discharged. If however you were trying to start your engine and the voltmeter came off the input to the starter solenoid....commonly used junction point for 12v distribution, and you got 10v while trying to start, then yes your battery could be as I mentioned in the first paragraph or as Chris said your terminals could be cruded up.

Mark