I need help with a starting problem

[colvosview]

I am having a starting problem with the 1987 70hp on my classic Angler and would appreciate the thoughts of all the experienced people in this group. Sorry this is sort of long, but I want to give a complete picture.

We went out for a Sunday evening picnic a few days ago, and when we got back to the dock it was late so I decided to return the next day to flush the motor, put the canvas up, etc. Monday happened differently than expected, so I didn't get back until Tuesday (yesterday as I write.)

First thing I noticed was that I had left the battery selector switch on "BOTH"instead of "OFF". I wasn't too concerned, but I should have been. The starter would only crank very slowly, like one turn a second or less, on either battery. So I went home (boat is moored at my boss's waterfront home - nice perk!) and picked up chargers and extensions cords, got them connected, and ran some errands while they did their work. When I returned, one battery showed full charge so I tried starting the motor again, but the starter still did the same.

At this point the dock owner showed up with a charger with a starting circuit. We connected it and it cranked normally, but I only let it turn over twice because I hadn't connected water to the motor at this point, just to do a quick test. I turned the water on the earmuffs, jumped back in the boat thinking all would be well, turned the key, and it was back to slo mo. By now the second battery showed full charge so I tried it, with the same result.

By now I'm starting to be concerned about the residual salt water sitting in the motor this long, and I'm really ready to get this thing sorted. The batteries are 4 years old, and I know that with cars I've had batteries that showed full charge but wouldn't crank. The local NAPA had a deep cycle marine battery the right size in stock, so I went and got it and put it in place of the battery that showed full charge but wouldn't crank. I had to charge the new battery awhile, but when it showed full charge and I turned the key, still one crank per second or so.

The connections at the batteries look ok, as does the cable from the solenoid to the starter. My plan for today is to check the connections at the battery selector switch - especially the one that goes from the switch to the motor, since both batteries are having the identical problem.
What am I missing? Is there something in the battery/solenoid/starter circuit that could be damaged by the batteries being left on? The key was not even on the boat, so I'm not sure how anything like that could happen, but I'm not terribly smart about these things. Is the problem not related at all to the forgotten switch, and it's only a coincidence that my starter started going south at the same time? But if it's the starter, why did it crank normally with the starting current from the charger? And why did it do that only once?

I'm also feeling very stupid about not flushing the motor as soon as I got back to the dock. I told myself that leaving it overnight was no different than when we go on boat camping trips, but I've gotten wonderful service out of this motor for the 25 years I've had it, at least partially because I try to take care of it. I feel like I've let it down with my Sunday evening laziness! How quickly does corrosion start to occur, and when the motor will start, what can I do minimize damage? Thanks.

[ssobol]

I would try connecting a battery right up to the starter to see if that gives different results.

Not flushing the motor should not leave it so caked with salt that it cannot crank. The flushing is for corrosion control.

I've had batteries that were "fully" charged that could not crank very well. There is a difference between what the voltage is and how much current a battery can put out.

Starter motors can fail suddenly. Losing some of the windings will reduce the torque the motor can produce.

[colvosview]

ssobol, I wasn't thinking that corrosion would be locking up the motor. I'm just concerned about the corrosion in general as I go longer and longer without being able to run the motor to flush it. I took automotive jumper cables with me today so that I could go directly from the battery to the starter, and the starter still turned over very slowly. My next step is take the starter off and get it checked out, and replace it if necessary. I still don't understand why the starter spun nicely on the first try with the 850 amp circuit on the charger! Like I say, I'm really pretty clueless about this, but it looks like the starter will be easy enough to remove/replace.

[C-Wolfe]

Look for corrosion in both positive and negative circuits. You should take a voltage reading at the starter using the starter ground and compare to what you got at the battery. If that check out good I would have the batteries tested then the starter.

[thataway]

Relatively short charging will not fully charge a battery, but will give a "surface" charge which reads 12.7 volts. But there may be enough charge in the battery, especially a 4 year old battery to not have the cranking amps available. The 850 super charger (start boost) will have a lot of power to boost the battery voltage. I carry one of the Li battery jump starter and have started up to 400 hp diesel engines with one, where the boat had low batteries.

You charge the battery fully, which means a smart charger for at lest 24 hours. Then put a high restive load (battery load tested--most auto parts stores have one, or a cheapie from Harbor Freight.

Yes, there can be some corrosion on the battery cables, and best to check these by pulling, cleaning with wire brush, and brunishing the terminals.

Take the batteries to be load tested. A deep cycle battery may have. lower marine cranking amps.

Leaving the house battery 'on" there may be some "ghost" battery drain for GPS, Radio memories etc. In some boats these can drain the batteries.

No harm from the delay in flushing. Cruising boats go months between flushing the outboard. (I always did when it got to a marina, just using the flush port).

[colvosview]

Thanks, Bob. Always good info.

[ssobol]

FWIW, I had problems starting my truck once. The battery was about a year old. Took it to the auto parts store and had the test charge it and test it. They said the battery was fine. After the store charged it, it started my truck a grand total of once, then it wouldn't do it again. I just replaced the battery and the truck has been fine since.

Another FWIW, I had a battery in my boat. It was weak starting the motor. I took that battery to be tested under warranty (4th year out of 5). Again, they tested it and said it was fine (it was a different place). I was not convinced so I just bought a new battery.

[colvosview]

Problem solved (Ihope). I got a new starter today from Sound Starters in Tacoma. Now it's turning over faster than it ever has, and started almost immediately.