Any harm in "jump starting" the starter?

ZmOz

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Aug 13, 2003
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I have a '74 Mercury 1500 that really has alot of trouble cold starting unless I jump start it. (with one of those portable jumper things) The battery is new and has I think 540 cranking amps. I'm thinking I might need to replace the battery cables, they look pretty old and I think the gauge might be too small for their length. To test this I would like to hook some jumper cables directly to the starter and see if it starts faster. Would this be a bad idea for any reason?
 

andrewkafp

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Mar 15, 2003
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Re: Any harm in "jump starting" the starter?

Manual says no problems with jump starting, but you have to ask "Why does it need so much cranking"? Does the choke fully close the butterfies ? Is it getting plenty of fuel and spark ? Excessive cranking can damage the starter too.. so I read. You need to crank briefly, not for long duartion.. The starter will heat up and probably burn comutator or brushes..
 

ZmOz

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Re: Any harm in "jump starting" the starter?

I don't know why it needs so much cranking, that is what I am trying to figure out. I don't mean jump starting like hooking up another battery to the battery, but rather, hooking a battery directly to the starter with short cables.
 

andrewkafp

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Re: Any harm in "jump starting" the starter?

That is OK too, but make sure that there are no separate cables running with main lead that won't be connected when you jump it. You can damage the rectifier and Ignition with some simple errors.
 

Just Jed

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Jul 21, 2003
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Re: Any harm in "jump starting" the starter?

If you jump start it by touching the cable to the contacts on the starter you will get to crank the motor but will melt the contact that you touch. Try first at the starter solonoid. If you indeed want to test directly at the starter, connect the ground(-) booster cable up to the ground on the starter, hook a short stout heavy gauge cable to the pos (+) on the starter then make contact with your pos (+) booster cable to the end of that.
 

petryshyn

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Re: Any harm in "jump starting" the starter?

ZmOz<br />There is no harm in jump starting in the appropriate manner, but it won't tell you much....a few voltage readings will tell you more.<br /><br />While cranking, measure the voltage at the battery. Measure the voltage at the starter. The 2 readings should be within 1 volt of each other. If not, look for connections-cables-solenoid problems. If the battery voltage is lower than 9.5 while cranking, the battery may be bad or in need of charging. If battery voltage level is ok, and the difference between battery and starter is less than 1 volt (and unit still cranks slowly) look to the starter for issues....
 

roscoe

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Re: Any harm in "jump starting" the starter?

Your original post refers to cold starting, but you don't say if it is a problem getting the starter and engine to turn over, or a problem getting the engine to fire before the battery wears down.<br /><br />How long does it take to get it started? 20 seconds?<br />Does starter spin with one battery?<br />Does starter engage the flywheel?<br />Does flywheel turn? Very slowly or fast?<br /><br />With the info you gave us, this could be a fuel or starting procedure problem.
 

ZmOz

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Re: Any harm in "jump starting" the starter?

Thanks guys, I think I've got it mostly figured out. Part of it is just that I have a cheap battery I think. When I first got the boat, it wouldn't start unless I jumped it cold, it just wouldn't turn fast enough, sometimes the starter wouldn't even engage the flywheel. Now that I've got it running better, it starts ok with just one battery. I think I need to replace the battery cables anyway, they are looking pretty old and worn.
 
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