Re: 1970 evinrude lightwin 4 hp not running smoothly at high rpm
okay, I was in a bit of a hurry while writing about my problem, here are the anwsers to your questions. 1. coils: along with the points, capacitors and other parts that go on the magneto under the flywheel I replaced both coils with brand new ones. 2. yes, when I cleaned the carb I put in a new kit. I could possibly take the carb apart again and see if the float is sitting correctly...
I should also mention, I just checked the compression about 15 minutes ago and the gauge read 93 psi in the top cylinder and 91 psi in the bottom cylinder. I'm not very experienced with this kind of stuff but I think that seems pretty good for this size of motor...
as for history... I bought this motor off someone on craigslist for 160$, he gave me a demo in a barrel before I bought it, and it ran farely well (he was running it on a 40:1 mix, I now run it at 50:1) I don't remember if it was having the high speed problem at that point in time though... he also changed the gearcase oil when he bought it. He said he had owned it for about 3 weeks, before that he bought it from another guy who was the original owner of the motor. upon inspection from top to bottom, everything looked okay, corrosion on the prop most likely from running it in salt water, the top and the bottom part of the motor was re-painted a while back, I know it was a while back because the paint was coming off in some places, I looked at the engine and it looked like it was re-painted as well, though i'm not sure. Upon lifting the flywheel I found an old, cracked coil that seemed to have salt water corrosion on it, and another newer coil that was replaced by the guy I bought the motor from, I replaced both. all the ignition parts (points, capacitors) looked okay, I replaced them anyways... I then put the flywheel back on, and put the cover back on the motor and noticed that it had been re-painted, possibly to cover up a dent/crack I noticed on the corner, indicating that the motor may have been dropped.....
anyways, sorry about the long post, but to summarize, what do you suggest I do at this point?
[UPDATE] the fluctuations in speed werent exactly 5 secs up, 5 secs down etc... it changes, say sometimes 5 seconds up, 3 seconds down, or 7 seconds down, 4 seconds up (if you understand what i'm trying to say at all) the 5 seconds up/down was just an average.
[UPDATE #2] I also forgot to say that the fuel tank I purchased seperately from someone else was covered in varnish on the inside because it sat so long, so I sprayed a quarter cup carb cleaner in the tank with a quarter cup fresh gas, put a chain in, and shook it to free up the varnish, I then poured out the varnish, carb cleaner, and gas. I then put in a cup of gas and swished it around to get anything off the walls, though there may have still been some varnish/carb cleaner solution in the tank when I filled it up and ran the motor off of it, though I would imagine that would not be the source of the problem, since it would be so diluted it would be pretty much impossible to notice.
