'91 90HP Johnson Barely Turning Over

The motor on my recently purchased boat has ran beautifully the last couple of weeks, no hard cold cranking at all, been firing right up. The last time I had it out, i notice that when I try to crank it, it was turning over slowly until it fired, then it ran great. Last night I tried to launch it. Did the same thing but worse, barely turning over, and very slowly, like twice per second, not enough to fire it up. I am going to get the battery checked right know, thinking that it just didn't have enough juice to turn it over fast enough, b/c last week once it cranked it was ok. If it's not the battery, could it be a bad starter. What are the symptoms of a starter going out. Any other thoughts/suggestions?

Thanks!

Re: '91 90HP Johnson Barely Turning Over

several suspects come to mind here from your description.

once you determine its not the battery...

- you positive or negative battey connection may have corrosion on it, enough so that it can no longer deliver the cold-cranking amps needed to readily turn the motor over. Clean all your connections first.

- motor resistance may be increasing. (an impeller for instance) take the spark plugs out and turn the flywheel by hand...it should rotate be easily.

- your engine may only be producing enough charge to run the motor but not recharge the battery. test voltage regulator.

- and of course, your starter could be going on you. remove and have it load tested.

Re: '91 90HP Johnson Barely Turning Over

90% of starter problems are bad connections. remove and clean both ends of the battery cables, so that they are shiney, also the cable from the solenoid to starter. check for nicks in the cables. and make sure the connectors are on the wire good. the cable tend to corrode from the inside out, if nicked, corroded wires, and connections, heat up and cause resistance to the follow of electricity, thus the starter doesn't get enough. you can also take jumper cable pos battery post to large post on starter. with a good connection, the engine should spin. then if the starter is good clean everything and retest. then trouble shoot solenoid. starters can be rebuit at a starter/alternator shop, much cheaper than a new one.

also have the battery load tested at the auto parts store, free, i've had new batteries go bad

Re: '91 90HP Johnson Barely Turning Over

Does your boat have a voltmeter? Start the engine and see what it reads. If its less than 12.6 volts at 1500 rpm the battery is not charging. At speed the meter should read 13.2 - 14.6 (give or take a tad) indicating the battery is charging (since static battery voltage is 12.6). If the boat does not have a voltmeter, you can use a hand held multitester (volt-ohm-milliamp meter) obtained from any home improvement store (electrical dept) for less than $20. But it does appear the battery is not being charged or is simply going bad.

Re: '91 90HP Johnson Barely Turning Over

Before I took the battery, I was able to jump the motor off my truck, ran great (with muffs) multi-meter read about 11.9 static and 11.12 while running, so I'm not charging. Got some corrosion on the positive side, going to clean it up and get the battery checked just for good measure. If corrosion is my problem, could the alternator still be good, and just not able to send a charge back to the battery b/c of the corrosion.

Thanks for the help!!!!!

Re: '91 90HP Johnson Barely Turning Over

Got the battery checked, its ok and fully charged now (not from motor). Cleaned all the corrosion, then got called by wife to go eat, then dark. I will get after everything again in the morning. The voltmeter on the boat is in the yellow at 12v, and green at 13+, and green all the way up to 18V. I believe that the battery is a 12V. Doesn't say on it, but I thought that's what just about all batteries were. so full charged battery reads about 13. Will find out in the morning if it was the corrosion prohibiting the battery from charging or if the alternator is bad. This outboard is my first, rebuilt a few ford 289's but no outboards. I figured out what just about everything is with the cowl off, but don't know where the alternator is, and if I can replace on my own? Any help would be helpful on this.

Thanks,
Kyle