Strange Breakup with '87 Evinrude 140HP

[eiapro]

Hey Y'all... it's me again! Last year, during warmup, I'd start off slow, then gradually get to 30 MPH and after a mile or so, hit it to about 60MPH hard, but have noticed that I am getting a bad breakup lately like someone is taking the plug wires off+on continuously. I then stop, take off the hood (motor running), and manually open the butterfly's to let in air, when it hits about 4500RPM, I do it 2 more times, put the hood back on... no more breakup. This is continuously getting to where it happens almost every time we go out now. Any ideas where to look? This Pro-Craft is a Great boat, and I want to get these minor things fixed to do some serious fishin. Thanks y'all.

 

[WillyBWright]

Re: Strange Breakup with '87 Evinrude 140HP

Does that have a primer or a choke? If a primer, the primer may be dribbling gas causing an over-rich condition. Opening the throttle would help clear it out. But it sounds more like ignition. If you have a timing light, you can test for spark on each cylinder. If the light is flashing, the sparkplug is firing. Tape the trigger on and put it in an easy place to see. Take successive test runs, one for each plug lead. If it's ignition related, you'll see it.

 

[eiapro]

Re: Strange Breakup with '87 Evinrude 140HP

It has a hand-bulb primer, and an elec. push-key choke. I replaced the plugs with some that had no electrode, same issue. I remember replacing a small round thing that caused my tach to stop responding. My boat guy said it also controlled a limited charge to the battery?! Well, I noticed that I still ocasionally lose tach., but cannot pinpoint the reason. Where should I begin? Thanks again. If y'all need pics, email me: (tennesseevalleysoundcreations@frontiernet.net)

 

[eiapro]

Re: Strange Breakup with '87 Evinrude 140HP

Any of you all have any ideas yet? I don't know where to start looking for anything... common or not common, but I can't deal with this breakup another year, and where I currently reside, the labor rate is $77 per hour!!... But... I am capable if I know where to begin looking. Thanks again y'all.

 

[ezeke]

Re: Strange Breakup with '87 Evinrude 140HP

Not sure that I understand what is happening, but you may be getting air into your fuel lines. If you are running on a near empty tank, you can do this on turns. If you have any air leaks, the air has no place to go but through the system. Can cause misfires, scoring.<br /><br />How old is your propeller?<br /><br />More often than not, when a rectifier (tach and charging issues) goes bad it is due to loose wires or bad wires on the battery cables. You may want to inspect and thoroughly clean the battery wiring at the battery end as well as at the motor.<br /><br />Do you see any indication of exhaust leaking into the motor housing?

 

[eiapro]

Re: Strange Breakup with '87 Evinrude 140HP

I have a new SS prop, I usually have a full tank when I start the day out on the lake, I have just recently re-wired everything from the battery boxes all the way to the trollin motor, so maybe that will cover the rectifier. I will see what happens in a few wks. now when I 1st take it out. If it starts skipping again, I just don't know, but I am about 70% it will because everything else seems ok. A few questions I have are: How often can coils go bad, what causes it, how can I test them, etc. and: What about the CDI unit.... can this cause the problem? and same as above, how to check, what cause, etc. Thanks again, y'all.