mudman Posted May 25, 2009 Share Posted May 25, 2009 I was running the other day and now my engine won't idle. I have this 1979EA71 in a boat. I just got a weber from Jerry and man oh man, the thing was running fine. I noticed that the volt meter was at 12V when I left the dock, and then up to 16V at 3000 rpm. It then dropped back down to 12V, probably because I fried it. By the time it started running bad, I was at 10V. It would not idle, but would run fine at 2000 rpm. At idle the engine would pulse, and then die within a few seconds. Well, I got it home, and if I pump the gas, it will run for a few seconds and die. Seems to me a vac leak, or carb problems. I plugged the PCV valve and it would run, but very rough. So now I'm thinking PCV valve. Changed it, and no difference. I charged the batery this morning, and now it will idle again. I ordered a new alternator, but I can't see how this is my problem. How could a bad alternator have an engine run at 2000 rpm, but at idle it pulses and dies? Does anyone think that it is the alternator, or should I try something else? First thoughts are crap in jets or intake leak, but I am 90% sure that all is ok with fuel delivery. Link to comment Share on other sites More sharing options...
opus Posted May 25, 2009 Share Posted May 25, 2009 I'm having the same issue with an ea82. Try taking off the battery wire on the back of the alternator. See if it runs well with that off, leave the other wires on. Remember, that wire will be hot, dont let it touch anything when its running. Curious on behalf of your issue and my issue. Link to comment Share on other sites More sharing options...
mudman Posted May 25, 2009 Author Share Posted May 25, 2009 I removed the entire alternator, and taped the wires. Starts right up now, but I think that it is trying to trick me. I dont think it likes me very much. I hit the gas a few times, and it seemed responsive. This is of course after I charged the battery back up. Link to comment Share on other sites More sharing options...
Jerry DeMoss Posted May 26, 2009 Share Posted May 26, 2009 Sent you a pm about what I think it could be mudman. Link to comment Share on other sites More sharing options...
Loyale 2.7 Turbo Posted May 26, 2009 Share Posted May 26, 2009 Well, it seems Like the Alternator is Bad... But Maybe it is Just its Wiring... Could I Ask you Pictures of your Subaru Engined Sail Boat? ... I Really Like Boats... Kind Regards. Link to comment Share on other sites More sharing options...
mudman Posted May 26, 2009 Author Share Posted May 26, 2009 Well, I plugged the PCV valve, and it ran the same with or without it. I am going to plate off the EGR. Seems to me to be the alternator. Is it possible that a defective alternator and a weak battery would cause the engine to stumble on idle? Would it throw a weak spark across the plugs? I just dont get it. If the spark is weak at idle, wouldn't it be weak at higher rpm also? If I pump the gas a few times it will idle, so it seems that I can rule out spark. I'm completely confused here. Link to comment Share on other sites More sharing options...
Spiffy Posted May 26, 2009 Share Posted May 26, 2009 if you have a weak battery and alternator then you're not getting enough juice... revving it a little gets the alternator going and makes more juice and everything gets happier... could also be a bad ground... sounds like an alternator/battery issue... Link to comment Share on other sites More sharing options...
mudman Posted May 27, 2009 Author Share Posted May 27, 2009 I changed out the alternator last night and I am now getting 14.5V, but it still seems to have a bad idle. I then blocked the EGR and it went from sounding poor, back to sounding great, but only for about 2 minuites. The EGR was blocked, the PCV valve blocked, new alternator, and the valve covers venting to atmosphere. Should sound great at idle, but it still does not. Oh yeah, the entire engine was rebuilt about 6 months ago. It sounded great for quite a while and all of a sudden it just started this crap. I started checking the Disty. How much play should it have at the rotor? I have maybe .003 horizontal and maybe as much as .006 up and down. Is this too much? Perhaps this is my idle problem? It still purrs at 3000 rpm no matter what is hooked up or blocked off. But when I pump the gas a few times, the engine starts right up and sounds great until that fuel is exhausted. Maybe carb problems? What should I be looking for? Carb is rebuilt and should be worry free. I have a fuel filter, so there should not be any trash in there. Don't know much about the Webers either. It is narrowed down to either disty or carb. Is there any way to trouble shoot these items without buying something new. A reman disty is around 125 bucks, and I'm not ready to spend that yet. Link to comment Share on other sites More sharing options...
the sucker king Posted May 28, 2009 Share Posted May 28, 2009 The fuel pump runs off of the alternator on those old ones, It's a "safety feature". If you are not charging right at the alt, your fuel pump can and will stop getting a signal. You can trouble shoot this by hotwiring your fuel pump when you encounter the problem. The logic behind this setup is that if you were to crash and cut the fuel line, the pump will not continue to spew gas all over the place because without the engine running, ie the alternator spinning, the pump gets no signal. Link to comment Share on other sites More sharing options...
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