Electrical problems on 1984 140 Evinrude

[Evi140]

Only had this motor for 4 weeks and havn't had much to do with marine stuff before. I have 2 issues that may be connected.

1st - Tacho is not accurate. Works some times, but most of the time it is reading way to high.

2nd I have a miss at low rpm. - Cleaned electrical connections on control lead and replaced one faulty spark plug lead (open circuit when moved into different position). This has improved, but definatlyu not fixed. Seems worse once hot. Motor stalls mostly when back at boat ramp (hot).

Could the two be related? Seems to miss lots more when tacho plays up.

Any help

 

[jtexas]

Re: Electrical problems on 1984 140 Evinrude

1. check to be sure the tach is set at "6p"
2. compression test
3. spark test - look for a sharp blue spark across a 1/2" gap (spark tester, couple bucks at auto parts store)
4. what do the spark plugs look like?

Any chance its overheating? Be a good idea to test the overtemp horn, also change the water pump impeller, if you don't know when it was last done.

 

[emdsapmgr]

Re: Electrical problems on 1984 140 Evinrude

Erratic tachs are frequently caused by faulty rectifier/regulators. When these go bad, the engine also quits charging the battery. If you have a timing light, put it on each lead when it starts to miss. It should tell you a lot about the firing and strength of the spark. Esp, if it is isolated to just one plug. You will need someone else to drive the boat while you do this check.

 

[R.Johnson]

Re: Electrical problems on 1984 140 Evinrude

A timing light is just that! a timing light, It is a poor trouble shooting tool most times'. What is needed here is a peak reaking volt meter, but not found in most home shops'..It will check ign. sensor, charge coil, and power pak out-put, througout the RPM range.Without one you are guessing, and probably spending alot of money. Find some one who has one,

 

[hoeser]

Re: Electrical problems on 1984 140 Evinrude

I have this engine and had tach problems but it was all related to a bad regulator... pricey... is it charging the battery? If not, it's likely the regulator. Check voltage of battery when engine is not running, and see if it increases when it is running. At fast idle you should see over 13V.

 

[Evi140]

Re: Electrical problems on 1984 140 Evinrude

Thanks all, I have found a faulty rectifier (reg is seperate) - Have only ran for 2 min on muffs. Tacho looks OK, but is set to 4. I would think for a V4 this would be correct? I was suspect of charging as I had a dead battery and was thinking it was a bad battery, but it turns out it was charging. Funny one that as I have a dc tong tester which showed 5 amp at idle..

Anyway motor is idling higher now and doesn't seem to have a miss, perhaps the rectifier was pulsing eath causing engine problems. I was advised to clean every earth in case and as all other terminals were dirty I will do this. Won't know for sure until this week end.

Thanks all