90 TLDI starting problem

My 2003 90hp TLDI has developed a starting problem recently. I know I need to take it in to my dealer eventually, but I'm not sure there's enough of a symptom yet for him to diagnose. I have a two battery system. The starting battery is a group 27 with an excess of CCA capacity, and the house battery is also rated at the mfgr's CCA specification. I towed the boat 500 miles up to our camp in Canada two weeks ago. We got there in the evening, loaded the boat, it started up normally, and we went 7 miles downriver to our camp. Next morning, after the boat was in the water all night on a mooring, and everything had a heavy layer of dew on it, I went to start the boat on the group 27 battery. It turned over very slowly but wouldn't fire, and the low voltage alarm went off while cranking. I switched to the other battery....same thing. It would crank a few times, the alarm would sound, and the motor wouldn't fire. I switched to both batteries, and the motor started. It ran fine every time I re-started it the rest of the day. The next morning, and every morning afterward, it was the same story...hard to start on either battery, but would start with the battery switch on the "both" setting. I knew my battery switch was getting corroded, so I installed a new one when I got home a week later. I also charged the starting battery on the trickle charger for a few days and cleaned and tightened the battery connections, but the problem persists on a cold start only. Both of my batteries are fully charged, and read 12.6 volts when I got back from vacation, so I don't think that the battery condition was at fault. I keep hoping the problem will get worse so it can be diagnosed, but after the first cold start in the am, it will start normally the rest of the day, even if its shut off for several hours in between.

Any ideas? Or should I just take it in to the dealer now?

Re: 90 TLDI starting problem

What was the CCA when the batteries were new and how old are they now?

Re: 90 TLDI starting problem

The Group 27 starting battery is 860CCA and 1050MCA. It's in its second season of use. Per the shop manual, it needs a 600CCA or a 750MCA battry.

I can't get to the other battery easily to read it. I can get to it tomorrow.

Re: 90 TLDI starting problem

It's almost certainly a battery/cable issue. The engine is 4 to 5 years old and you probably have some loss due to resistance in the cables. Combine that with a 2 year old battery (Ignore the manual and go with a 1000 CCA) and your probably at the breakpoint. Your local dealer can tell you for sure though.

Re: 90 TLDI starting problem

I'll do a resistance/continuity test on the cables first. If they check out, I can take the starting battery to be load tested. If I can eliminate those two items, or replace if they prove faulty, maybe I can save the trip to the dealer.

Elvin, about a year ago you posted the make and specs of the battry you use for these systems. Could you refresh my memory? If I remember, they are available locally. Exide?

Re: 90 TLDI starting problem

I think every brand of battery has one in the correct size range, which I recommend at 1000 CCA. Less is fine, but dip below 900 and you aree looking at an average service life of two years.

Re: 90 TLDI starting problem

Elvin, I hate to pester you, especially since you spend a lot of time helping people out on this board on a daily basis, but I need some help. On the Exide battery specification chart, I had to go all the way up to a size 4D (20 7/8" x 8 1/2" x 9 5/8") battery to find one with a CCA at 0 degrees of at least 1000. I think these 4D batteries weigh somewhere in the neighborhood of 200#.

http://www.exide.com/pdf/exide_specs_april_2003.pdf

By "CCA 1000", do you mean cold cranking amps at 0 degrees, or cranking amps at 32 degrees?

Thanks,

Jim

Re: 90 TLDI starting problem

At 32. At 0 it would be around 790 to 810 on the rating. You always want to go 40% larger than the minimum required on a battery due to their tendency to lose power from the date they are put into service. Three years is about all anyone should hope for on service life and it's not unusual to get only two.

Re: 90 TLDI starting problem

Ok, thanks. Apparently then my starting battery is sufficient at 1050 CA at 32 degrees. It's this one:

http://www.trojan-battery.com/Products/ProductSpec.aspx?Name=27SM-1100

It's just over two years old. I'm taking it in tomorrow to be tested before I do anything else.