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1977 140hp Evinrude trouble

Well, the wiring I can see took about 30 minutes to check it out good. The rest is in a harness but I don't see any damage to any wires. No burnt spots or something that looks like it's acrhing or shorting out.
 
It reminds me of the 53 Ford PU I restored several years ago. It ran like a scalded dog then all at once, it just shut off. Start right back, run for a few miles then shut off, all at once. Took a while but it was vapor locking. Nearly sucked the gas tank behind the seat into a pop can. Once the engine shut off, it would backwash and the process would start over again. That's what the shut down reminds me of. I'll be the first to say I'm wrong if this turns out to be electrical but it sure doesn't act like it looses fire when it shuts off. Doesn't act like it's running out of fuel because it doesn't spitter or sputter but I've felt from the start, it's either fuel or air. I've checked or replaced everything in the fuel, as far as from the tank to the carb. I've removed the plugs several times after this happens and they are wet, maybe not flooded but certainly not starved of fuel.
 
2 different mechanics have set the timing and adjusted the linkages on the motor and it hasn't changed a thing. Hard to think they both wouldn't know how to do that, know what I mean?
 
The first step in fuel issues... Does the priming bulb stay hard after the engine dies?
Does pumping the priming bulb keep the engine running?

It's hard to believe that experienced mechanics would miss something simple, but it happens.
 
This shop / mechanics spent 27 hrs trouble shooting your motor ??---What all did they check ??----Have you removed the bypass covers yet ?----Or not sure why that might help you ?
 
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@stingerbassboat If Racerone wants you to check something, it's for a very good reason. He is one of the most knowledgeable contributors on the forum (if I'm lucky, he might rebuild my ailing 115 this fall...).
Unlike in a car where the piston rings are free to rotate, in a two stroke, the rings are located by a pin and should not rotate. Imagine what would happen if one of the splits
in the ring rotated over a port...
 
Well guys, I'm in the same BOAT, sorta speaking. If you read my first paragraph, you can see, these guys have replaced or checked about all the things that can cause this issue. I done a lot of research but typing, ENGINE RUNS ON MUFFS BUT NOT IN WATER, well, it brings up all kinds of solutions. One has to imagine even if these mechanics didn't replace some of the ideas on here, what they did replace and check pretty much ruled out some of those things. I've dealt with more wire shorts than I care to mention but, one common symptom with just about, if not all wire shortage issues is the fact it won't behave the same way over and over. Loading the boat, bouncing on waves, pulling it on a trailer, etc. etc. Whats the odds it doesn't move those wires and change the symptoms. Completely broken wire, yes, I get that but it seems when it comes to this issue, it's about a shorted wire or broken insulation which should cause the problem to change when that wire is moved the least amount. All these mechanics, as you can see by the parts replaced, believe it to be a electrical part or at least problem. The primer bulb pumps up and gets hard. I can squeeze it while the motor is running and it makes absolutely no difference. It never looses it's hardness even when the engine dies. O yea, it's new as well, forgot I replaced it way back. I still have the old timing plate base, I'm going to remove the new one and put the old one back in, not to fix it but to see if it takes the motor back to the original problem I had. I mean, before it would run, take fuel even if I was doing it at the carb but now it simply won't take any fuel. I can't help but wonder why everything changed after I had the timing base plate replaced. This problem started by it running great as long as you didn't run it wide open for a 1/4 mile, the original problem wasn't anywhere near as severe as the one I have now. If for some reason that timing base plate won't work right on my motor, we are like dogs chasing our tail. At least if I get back to the original symptoms, it might make sense what's causing the problem. I talked with David today, he assured me that he checked the reed valves and there's nothing wrong with them. When I picked up the boat, checking that exhaust tube was the only thing he said he forgot to check while he was working on the motor but I dropped the lower unit and there's no blockage, at least not on that lower portion of the motor. It's hard to think the plate isn't working properly and none of these mechanics would figure that out but I just keep wondering why the symptoms changed after it was replaced. Just seems to coincidental to me when before, no matter what I replaced or checked, it would run good cold but then shut off. Once it shut down, it acted that way until I took it back to the lake to test it...Danny
 
1st, I want to thank each one of you for taking the time to try to help me fix my motor. Well, I swapped out the CDI timing plate I bought for my original one today. Took it to the lake and other than the linkages need re-adjusting, it ran good. Obviously the timing base plate was either a bad one or it's not the one for my motor as CDI claims it is. I believe once the linkages/timing are adjusted properly, it will be back to running better than before. When fdrgator mentioned that the timing has to be perfect for the throttle to open and take fuel, I knew then, it had to be that timing plate. Everything changed after it was replaced. If the timing base plate would have been good, this wouldn't have been so complicated. I think the stator the 3rd mechanic installed was the problem. It could have been the rectifier or the crankshaft seals but I believe it was the stator. I have to defend these mechanics just a little because after the timing plate was installed, there wasn't much reason to look at it as the problem, so they were chasing their tales trying to figure out what else it could be. Just wanted to write this in case someone else has the same problem and maybe it will save them some time. Haven't been fishing in 5 months, looking forward to going in the next couple of weeks. Thanks again and have a blessed day...Danny
 
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