1979 Merc 900e starter issues

zanderman111

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Mar 15, 2009
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28
I recently purchased a 16 foot Glasspar boat with a 1979 90hp Merc 6cyl. The boat came with two batteries, I was told they were good. Put ear muffs on the Merc and turned the key. The starter cranked really slow and weak for about 2 seconds, then took off like crazy (though it took the engine several seconds to turn over). Once running, it ran great. I was suspicious of the batteries being weak, but put a volt meter on them and they were reading ~13 volts so I thought nothing more of it. Took it out to the lake and put it in the water, and tried starting it. Again I got a very weak crank out of the starter, only this time it was not enough to kick the engine over, just cranked very slowly. Very disappointed, I went home and had the batteries tested at Wal-Mart. They said both of them were shot. I bought a new battery (750cca) and hooked everything up to just the one battery (which should be plenty), and tried starting it again with the earmuffs. Again, I got the same slow crank initially for about 2 seconds, then the starter took off like a scared rabbit and the engine fired up about 5 seconds later. Now I was suspicious that it wasn't just the battery. I started it several times in the driveway with the hose and the slow initial crank, so I thought that was maybe just how it was. Took it back to the lake, turned the key, got the slow initial crank, then cranked normally for a few seconds until I let off the key. I turned the key a second time and got just a click. Absolutely nothing more. Voltage on the battery was fine, and the hydraulic pump for the tilt worked normally, but no crank, just a click. Now im thinking its the starter. Any thoughts? I took the starter off and during the disassembly, I noticed that the gears on the starter were engaged with the gears of the flywheel or crank, whichever its called. Are they supposed to be permanently engaged like this? Or are they supposed to disengage after starting? Any and all information/help is appreciated! Thanks
 

Laddies

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Sep 10, 2004
Messages
12,218
Re: 1979 Merc 900e starter issues

Yes, it's the starter, probably bad brushes
 

bullbat

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Mar 10, 2009
Messages
152
Re: 1979 Merc 900e starter issues

my 77 1150 does the same thing and has since i replaced the start about 5 years ago but its till cranks every time just slow for the first turn or so of the engine but it sounds like ur starter has took a crap on ya
 

Chris1956

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Mar 25, 2004
Messages
28,074
Re: 1979 Merc 900e starter issues

Also check the condition of the battery cables. Sometimes they corrode under the insulation. If so, you should be able to feel it or see a bulge.
 

zanderman111

Cadet
Joined
Mar 15, 2009
Messages
28
Re: 1979 Merc 900e starter issues

Thanks for the insight. Ill take the starter in and have it checked out. What should I expect to pay for a fix/rebuild?
Also, what do you guys think or know about the starter being permanently engaged with the ring gear? Is it supposed to be like this? I know on other outboards there is a solenoid that pops the starter gear up and engages the ring gear then drops back down. Mine did not appear to do this, the starter seemed to be permanently engaged with the ring gear. Could this have been my problem and burnt out my starter?
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,074
Re: 1979 Merc 900e starter issues

The starter gear rides on a threaded shaft. When the motor spins, the inertia of the gear allows it to ride up the threads and engage the ring gear. When the motor fires, it spins the starter gear back down. if yours stays up, it will ruin the starter, and perhaps the ring gear.

Aftermarket starters are available from ARCO for $150+ See if you can disengage the starter gear and oil the threaded shaft.
 

zanderman111

Cadet
Joined
Mar 15, 2009
Messages
28
Re: 1979 Merc 900e starter issues

Thanks! Took it in to a starter shop, they are doing a full repair for $85. They said they will have it back to me by tomorrow. Thanks again for all the help!
 
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