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85593E 1975 85hp Should start wont start

T

Tank62

New member
Okay, I pulled this fossil out of some farmer's barn & have been attempting to ressurect it. Fresh wire & external parts, carbs are clean with new gaskets, compression is good, gaps on spark plugs were checked, boots have spark jump.
Muffs were on, fuel line primed, power supply charged, on key turn the flywheel turns but I've got no combustion, just a starter motor spinning a flywheel by itself. Im no mechanic, just some guy with a wrench, a multimodel manual that seems kinda vague on some details, & access to the internet. Please assume I know nothing & keep to actual terms I can comprehend, lotta acronyms & stuff I dont know. Thanks in advance for whatever guidance you can provide. I'd like to finish this myself but I know when Im out of my depth knowledge wise, might be seeking a mechanic before long.
 
First thing to do is test your spark. It should jump a 7/16 gap. Use a spark tester with a moveable gap, not just holding the plug against the motor.
These old motors have to be turning over at more than 300 rpm before they will generate spark.
 
I know I have spark jump, that I've seen albeit without a spark tester, Im gonna have to look into one. I know video frames per sec may simply not be up to snuff, but watching videos on youtube I couldnt help but think their initial rotation of the flywheel seemed much faster. I'm wondering, maybe my starter motor isn't proper. I thought the one it came with was a tad slow & possibly bad but the one I ordered turned at about the same speed 🤔. Makes me wonder if while the site may claim its a suitable replacement that perhaps it isn't 🤔
 
If you have spark, and you're confident about your fuel supply, you may want to look at timing. If you don't have a timing light, you could start by pulling the flywheel to make sure the crank woodruff key isn't sheared.
 
Never heard of a crank woodruff key, sounds like I have some howework. I have a timing gun, an old blue thing, but always thought it was used for belt timing. Not sure it could work for a flywheel though, it was dad's & he is gone & that thing is older than me so pretty sure there is no manual. Maybe I'll get lucky & find a youtube video. As for the flywheel, it turns slower than it should.
 
Not sure what the speed was but neighbor said we were getting spark while I turned the key. Not like we had a tester for that but he was getting spark holding a screwdriver up to it or so he said 🤷‍♂️
 
The little half-disk that makes it stays in place on the shaft? Maybe you mean something else but if that is what you mean, that was fine by the look of it when I pulled the flywheel to take a look at the stator/magneto assembly underneath. I imagine if that sheered it'd be spinning faster anyway given it'd be spinning with nothing to secure it lol. But thats not what Im seeing, if anything its spinning slower than it probably should.
 
Yeah, pretty sure he is a welder & claims to have something of an engineering skill-set. Kicker is he doesnt come around much to help & as I've said before Im pretty much just a guy with access to a wrench & youtube lol. I'm very much learning as I go on this hunk of metal.
 
riopga said:
First thing to do is test your spark. It should jump a 7/16 gap. Use a spark tester with a moveable gap, not just holding the plug against the motor.
These old motors have to be turning over at more than 300 rpm before they will generate spark.
Click to expand...
Okay, I got one, threaded it out to 7/16. If there was a spark it was pretty faint. That said the wheel is moving slower than when we jumped it directly to the starter so maybe the neighbor helper did see a spark, ugh kinda frustrating.
 
clean grounds both ends. a solenoid drop test would be in order if its still not spinning fast enough. the battery: is it a marine cranking one with 450cca or higher?
 
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