Merc 50 Starter Problems

[X Ring]

First time out after a long winter, and my mid 70's Merc 50 is having starting problems. It will intermittantly start, but most of the time it catches momentarily then "whirs". I cleaned all battery, solenoid, and starter connections. I have pulled the starter, cleaned and oiled the shaft, and the drive gear easily travels up and down the worm gear. But when I try to start it, the drive gear comes up into the flywheel, and the shaft spins, but it doesn't turn the flywheel. It sounds like the shaft is spinning hard, but it's not engaging the drive gear.<br /><br />Any ideas or suggestions short of a new starter?

 

[boatingfool]

Re: Merc 50 Starter Problems

try to start it, the drive gear comes up into the flywheel, and the shaft spins, but it doesn't turn the flywheel.

If that is happening then how can the flywheel not be turning??

 

[X Ring]

Re: Merc 50 Starter Problems

Thanks for the response.<br /><br />I can see the bushing at the top of the shaft spin and hear it going, but it's like the shaft is spinning inside the drive gear.

 

[X Ring]

Re: Merc 50 Starter Problems

Update:<br />I found my meter and checked voltage at the starter wben cranking. If it came close to engaging, it was 9.49. After that it quickly jumped to 12.5 + as the shaft was spinning.<br /><br />Don't know if this will help diagnosis...

 

[tmcalavy]

Re: Merc 50 Starter Problems

sound like its loosing umph from the battery. my Merc 50 (mid 70s) won't even try to crank over unless the battery is fresh or freshly charged...needs those volts. otherwise, the manual shows three starter motors...bosch, delco-remy and something called prestolite. the drive gear comes off each one but manual doesn't say how. its possible the keeper is shot and the shaft is just spinning inside the pinion gear...never have disassembled mine so this is just a guess. does the flywheel turn easily? if not, lube the cyls with WD-40 top off the battery or get another and try it again. I bet the battery just isn't up to snuff. let us know how it goes.

 

[X Ring]

Re: Merc 50 Starter Problems

Battery is fully charged, and a meter shows it's getting power. Is it possible to test by using a jumper cable from the battery to the starter directly? Anything I need to know about testing this way, such as disconnecting the solenoid? I really don't think it will change things, but I do want to diagnose this fully.<br /><br />Any other ideas or suggestions?

 

[X Ring]

Re: Merc 50 Starter Problems

Tim Mc:<br />The flywheel does not turn easily, but it does turn. Are you saying to pull the plugs and spray WD40 into the cylinder? Won't that foul the plugs?<br /><br />For power, I topped off the charge, and did try and jump from the battery directly to the starter. Same result. I also put the charger on the battery, and put it on 50 amp "quick start" and hit the key. Same result.<br /><br />I am going to attempt to tear down the drive gear assembly from the shaft. That's the only thing I haven't tried. Otherwise I order a new starter tomorrow...

 

[tmcalavy]

Re: Merc 50 Starter Problems

well you've eliminated the weak battery/power possibility pretty well. like you, i would next pull the starter and examine how the pinion gear is held on the shaft. if its new starter time, check ebay they show up there pretty often. don't know what a new or rebuilt would cost...haven't gone down that trail...yet.

 

[tmcalavy]

Re: Merc 50 Starter Problems

and yeah, i was saying pull the plugs and lube the cylinders with a shot of wd40..couldn't hurt and won't foul the plugs. maybe you've got a case of cylinder corrosion that's making things drag. can't hurt.

 

[tmcalavy]

Re: Merc 50 Starter Problems

keep gettin ahead of myself tonite. try the wd40 then try your starter again. might save you the cost of a rebuilt or new starter.

 

[X Ring]

Re: Merc 50 Starter Problems

I have not yet tryed your tips, Tim. I had someone tell me about a scenario that exactly matches my problem. Evidently the clutch can go bad inside the drive gear, allowing the shaft to spin inside the drive gear. I can turn the gear by hand on the shaft, so it appears this is my problem. The drive gear has been ordered from Arco, twenty bucks plus second day shipping, hopefully I'm running under outboard power by mid week. I'll re-post when I find out for sure.

 

[jim dozier]

Re: Merc 50 Starter Problems

From your description it would have to be a bad starter drive gear setup.

 

[X Ring]

Re: Merc 50 Starter Problems

Well, got the new drive gear, installed it, and on the first crank it threw the locking ring at the top of the shaft, and locked up. Luckily it didn't damage the flywheel or the new drive gear. I kept the top bushing and the spring, but lost the locking ring. Where can I get one strong enough to handle the stress it receives? I don't think I can get something like this at Lowes.