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1998 Mercruiser 5.0 liter Starter Slow Crank / No Crank

Jmark62

New member
1998 Crownline / 5.0 liter Mercruiser / engine hours 160 - boat has started fine all Summer until about one month ago, after sitting unused for 1 and 1/2 months , took boat to lake, battery could not pull lower unit up and bilge fan was turning very slow. I replaced the battery (625 CCA) as the old one was 5 years old. Now when I crank the engine it turns over very slow or not at all. Battery gauge on dashboard reads about 12 V. boat is stored on a trailer, tilted with bilge plug open to keep any water draining out so starter has never been submerged. Am I looking at a bad starter? Starter has not shown any slow crank symptoms ever until now. Boat has always been in fresh water.
 
could be the starter if original, they dont last forever. other causes dirty connections at the cables, the starter post and the engine block neg connection
 
Do you have marine grade cables to your battery??? It's a 1998 boat... 1998 cables?? Connected to the big posts on the battery or to the screw terminals? Cable ends if connected to the screw terminals must be scrupulously cleaned (filed/wire brushed). If to posts, must use post cleaning tool on both post and connector on wire. If on screws, must use stainless nut and a separate lock washer... no wingnuts or nyloks. Also... newly purchased batteries should spend the night on a good battery charger before they are installed. They rarely come "fully charged". Measure the voltage across the battery terminals at the battery when cranking, (should be above 10.5V) bad out of the box batteries are not unknown.
 
I bought the boat used several years ago, cannot tell if the cables are marine grade. The hook up to the positive post on the battery is a clamp that squeezes onto the copper strands from the battery cable. This clamp is one piece with the circular lead fitting that slips over the battery post and then tightens with a small bolt. ( I hope this makes sense).
 
typical automotive type, remove them from the battery posts, clean them and clean the posts , install and coat with grease
A better option is to use a crimp on connector or better still marine grade cables with copper ends, not steel like automotive cables.
 
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