Logo
FULL SITE MENU

recently running 1985 50 hp won't start

F

fiddlegeek

New member
I bought this engine this summer and it was running well when I bought it. The remote was broken (ignition still working, but shifter broken), so I bought a new one and installed it. It started fine, but when it came time to kill the engine, it wouldn't shut off - I had gotten the flameout wire hooked up incorrectly. I let it run for a while, and then choked it out. It hasn't started since. I've put in new spark plugs and tested for spark. Compression is a little low maybe but I haven't been able to test after the engine has been warmed up. The carbs were a little leaky, so I've put in new fuel pump/ gaskets and fuel lines and cleaned the carb and bought fresh non-ethanol fuel. I even hooked up the old remote as I knew the ignition/ wiring to be working on that remote. I've checked for blown fuses. I've disconnected the flameout wire at the engine. The engine cranks, but doesn't even cough or try to start anymore. I'm super frustrated (and my kids too!). What happened? What am I missing? I could really use some help!
 
What are the actual compression values ?----Do you have a good battery , starter and battery cables.-----Does spark jump a gap of 3/8" or more on the 4 leads ?
 
racerone said:
What are the actual compression values ?----Do you have a good battery , starter and battery cables.-----Does spark jump a gap of 3/8" or more on the 4 leads ?
Click to expand...
Every time I go to “fix” something on this motor, it’s gets worse. I changed the battery terminal clamps as the old ones were a little loose on the post, made sure I had good battery charge on new battery. Now it won’t turn over.
So I was hoping to give you more exact info. I bought a spark tester, but obviously can’t use it without it turning over. To answer your question about compression- I didn’t write down values previously, but I believe the 4 cylinders were 85, 80, 70, 75 on a cold engine. What should compression be on a motor this size? Is this amount of difference between cylinders problematic?
 
thats pretty low compression.. Need to get it to crank to check for spark.. Perhaps an automotive remote starter switch connected to the solenoid (thats what I did, beats a screwdriver jump). Check the wires to the stator and trigger for corrosion or breaks if no spark.. probably should check them anyway.. Get a good manual or at least wiring diagrams or find them online. You can foul up the black box and more sending power someplace that calls for ground...BTW I fried my choke using it as a kill device.. mo money.. CDI electronics has some good troubleshooting downloads that go along with their components.. some of the best resources I found while trying to get my old machine running again.. I have the classic 50 4 cyl circa '84. Replaced stator, trigger, black box, controls and more..
 
rocknroj said:
thats pretty low compression.. Need to get it to crank to check for spark.. Perhaps an automotive remote starter switch connected to the solenoid (thats what I did, beats a screwdriver jump). Check the wires to the stator and trigger for corrosion or breaks if no spark.. probably should check them anyway.. Get a good manual or at least wiring diagrams or find them online. You can foul up the black box and more sending power someplace that calls for ground...BTW I fried my choke using it as a kill device.. mo money.. CDI electronics has some good troubleshooting downloads that go along with their components.. some of the best resources I found while trying to get my old machine running again.. I have the classic 50 4 cyl circa '84. Replaced stator, trigger, black box, controls and more..
Click to expand...
Thanks for info. What does low compression across all cylinders indicate? I’ll try to get ahold of a manual and some schematics. I may be in over my head. I’m handy but I’ll need to learn more about electrical side of motors to proceed. I have time to work on it but no way to work in heated area during cold winter!
I’m assuming you fried your electronic choke. This is manual choke.
 
I believe you can pull it over with a rope to check for spark.-----You can pull it over with rope and another gauge to check compression.-----If those are true compression values youi should remove intake bypass covers to inspect pistons and rings.-----Don't spend any beer tokens on parts till you determine the condition of this motor.----Did you install a new water pump impeller when you got this motor ??----Mixing gas and oil at 50:1 ratio ?
 
fwiw I put up a wiring diagram a while back on my flickr account when I was struggling with spark issues.. (see below) Not a clue on the compression.. Heard sometimes rings get stuck but all cylinders would leave me suspect... If it were me my first move would be to verify my gauge is working correctly, perhaps another engine..think there is an o-ring seal or 2 on mine.. Sometimes getting it to run can break things loose and improve compression.. I would agree with racerone on the money to put into that engine, but they do sound nice when running good and the power to weigh ratio is quite good. My reconditioning (including a crappy control unit) ran about $1k... That was all the ignition, the rectifier, trigger, stator, and cdi box... I believe that the cdielectronics company had some pretty good diagnostics on their website to go along with their products.. May be a good place to look, Thats where I learned about the stuff.. Better than the service manuals I had in many ways.. They tell you how to diagnose and test the components they sell in a clear and concise fashion.. Maybe you can isolate to a single component. I didn't know squat about it when I started.. One thing that will kill the black box is power to the kill terminal...also reversing polarity on the battery... beware the crappy new controls.you may find on amazon..... mine sent postive to the kill circuit via the lanyard kill... which I discovered too late of course.. lesson being that controls need to be tested before using...

anyway heres a link to the diagram I put up a while back... At least I think the link works...
https://flic.kr/p/2jGb7xp
.. will try attach as well here..
 
Back
Top