engine dies - electrical problem at temp?

[philiplvilain]

1996 100hp mercury outboard. Runs fine from cold start for about 90 minutes then dies sharply. Wont re-start unless left for about 30 minutes - i.e. it cools down.<br />Suspect some electrical component breaking down at temperature.<br />Have changed rectifier, stator, and power pack but problem persists<br />What can I try next ??

 

[Laddies]

Re: engine dies - electrical problem at temp?

That still sounds like a stator, did you test it warm with a DAV for output

 

[philiplvilain]

Re: engine dies - electrical problem at temp?

twin engines on boat.<br />swapped stator from 'good' engine to 'bad' engine and no change to problem.<br />Did notice that stator on bad engine has no ground wire while stator on good enngine has aground wire.<br />However, as I said, the problem persists on the bad engine, even with the swapped / ground wire stator from the good engine.<br />Did not do a DAV test. Do you still think I should do that ?

 

[KCLOST]

Re: engine dies - electrical problem at temp?

Switchbox... Switch out the switchboxes and retest... Easy test, just have to disconnect a bunch of wires running to it...<br /><br />Let us know...

 

[philiplvilain]

Re: engine dies - electrical problem at temp?

what's the switch box - the unit where the key goes or something on the powerhead ??

 

[wilde1j]

Re: engine dies - electrical problem at temp?

The switchbox (powerpack) is on the top rear of most powerheads. Try heating with a hairdrier or heat gun with the engine running and see what happens. Cold, it will probably test OK. Let us know the result.

 

[philiplvilain]

Re: engine dies - electrical problem at temp?

already changed power pack - see first posting above - problem persists

 

[KCLOST]

Re: engine dies - electrical problem at temp?

What is your serial# for the motor. <br /><br />The switchbox is usually located on the starboard side (driver's side) of the powerhead, it's a 3x5 or 4x6 inch flat box that has a bunch of different colored wires connected to it... It recieves both electric current from the stator as well as trigger signals from the trigger that "triggers" the charge to be released to the coils to fire the spark plugs at the proper time.

 

[KCLOST]

Re: engine dies - electrical problem at temp?

Missed it sorry....

 

[KCLOST]

Re: engine dies - electrical problem at temp?

The next time this happens see if it actually is electrical by testing for spark.. Use a spark gap tester to check each cylinder...

 

[philiplvilain]

Re: engine dies - electrical problem at temp?

OK – here’s an update. This weekend we switched the ‘sensor’ attached to the Power Pack (switch box) with the one from the ‘bad’ engine to the one on the ‘good’ engine.<br />Both engines ran fine. i.e on a three hour trip, neither one shut off.<br />This obviously is inconclusive. It may be that the sensor is the problem, but the running temp of the ‘good’ engine is different from the ‘bad’ engine.<br /><br />I will run them again next weekend and see what happens.<br /><br /><br />For those who suggested checking for spark when it shuts off, I could not do that since it did not shut off.<br /><br />For those who asked for serial / model number:<br /><br />OG 316487<br />1996 100 ELPTO

 

[philiplvilain]

Re: engine dies - electrical problem at temp?

Used the boat again this weekend.<br />Another 3 hours trouble free. <br />Problem seems to have 'fixed itself' with the swap of the parts.<br />Thanks to all for the help, advice and support.<br /><br />I guess we can end this thread now.