Cranks slow??????

wilson750

Petty Officer 1st Class
Joined
Nov 22, 2008
Messages
287
I finally got my key switched hooked up.. But the motor cranks real slow..The battery was full of charge also...Its a 86 mercury 115hp..

Ohh its been sitting for about 2 1/2 years also..
 

mthieme

Captain
Joined
Oct 6, 2007
Messages
3,270
Re: Cranks slow??????

So many questions...
Are the connections clean and tight?
Although the battery is fully charged, check with a hydrometer.
Try the battery out of your truck.
 

wilson750

Petty Officer 1st Class
Joined
Nov 22, 2008
Messages
287
Re: Cranks slow??????

I Will give that a shot...Who knows with all the connections, It has been sitting for about 2 1/2 years.. I just got it and have been messing with it..
 

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: Cranks slow??????

Pull the spark plugs, add about a half ounce of oil to each cylinder, turn the flywheel by hand to spread the oil.

Can you turn the motor over easily by hand?

Is there any stiff spots?

Ground the spark plug wires and try the starter, does it turn over at a more normal speed now?

Reinstall the plugs and crank it over, still good cranking speed?

Clean BOTH ends of both battery cables, also clean the cable from the starter to the relay, all clean, bright and tight.

Does it crank over better now?
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: Cranks slow??????

Disconnect all of the large guage wire from the battery to the engine block and the solenoid and from the solenoid to the starter. Check the wires for swollen or weak spots, clean all terminals thoroughly and reconnect.

The tiniest amount of corrosion in one of those terminals can cause voltage at the starter to be too low even with a fully charged battery.
 

wilson750

Petty Officer 1st Class
Joined
Nov 22, 2008
Messages
287
Re: Cranks slow??????

Thanks for the info.. i will try it again this week if it doesnt get cold!!
 
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