1972 Evinrude 100 hp starflite...ignition system issue?

[flamon]

I have recently acquired a boat that has a 1972 Evinrude 100hp starflite. I have taken it for a number of runs now and for the most part it has run really well. On our first run we went for about 20 mins before it started to cough at high revs (i.e. 4k) so we called it a day. The next day we went back down and this time it wouldn't start. At first we thought it was flooded so we took it back to our cabin, pulled the sparkies and let it sit in the sun for a while whilst we recharged the battery. We then took it down for another short run and after a while it did the same thing. We then went home as we believed it may be something to do with the carby...possibly flooding at start up and possible float/high speed jet issue. I had two carby kits at home ready for a rebuild as we thought that it was probably due for it.

I rebuilt the carbs and replaced the fuel hoses and we returned again 2 weeks later. Went much better and didn't happen on the first day, albeit we didn't go for long as the weather was turning sour. On the second day we went for a fish for a few hours and it seemed to be performing really well. Then as we returned to shore (it was 12 o'clock and we wanted beer) it began to happen and when we cut the engine and tried to restart it just didn't want to fire. Luckily we were at the boat ramp when this happened.

This then began me leading more towards a spark issue. A question I have is, how does this engine make its spark? Is it battery operated ignition, in that it charges the battery via the stator and uses power from the battery to make its spark. If so, if the rectifier was bad and the battery was getting low, would it begin to sputter and then not fire when we tried to restart?

Long post I know, but I felt it needed a decent explanation. I may be clutching at straws. Hopefully someone will be able to provide some trouble shooting tips Thanks in advance.

 

[oldcatamount]

Re: 1972 Evinrude 100 hp starflite...ignition system issue?

Your motor has an electronic ignition that makes it's own electricity once it's running. A weak battery will make the motor start hard and can have an effect on the performance of the motor, however, what you are describing sounds (to me) more like a fuel problem than an ignition problem. Is your fuel tank vented? Since the motor ran better after a carb re-build, I would check the fuel line connections and look for cracks or splits in the fuel line.

 

[flamon]

Re: 1972 Evinrude 100 hp starflite...ignition system issue?

Thanks for the reply. Yes the fuel tank is vented and was when the problem occurred. I have replaced most of the fuel hoses as a few of them were cracked. I will replace the other two that were difficult to get to and looked ok and see what happens. Just seems strange that it would only do it intermittently and only after running for a while.

Another few questions:

It seems that my ignition system has been altered as there is no longer a powerpack. Only ignition components I can see are:

- Ignition coil - aftermarket Bosch GT40
- OEM rectifier
- Looks like the standard stator and distributor.
- No powerpack.
- No Clipper circuit.

My questions are:

Why would it have been altered and how is it working without the power pack?
What does the power pack actually do?
What does the clipper circuit do?

I can post some pics if it helps

 

[oldcatamount]

Re: 1972 Evinrude 100 hp starflite...ignition system issue?

go to www.shop.evinrude.com and look up your motor ("72 100hp Evinrude). Click on the "Ignition" diagrahm and you'll see the entire system. It'll help you understand what you have there. Your problem could be something simple like a bad plug wire or a loose ground connection. If you have a DVA meter, do some testing before you start replacing stuff. CDI Electronics has a great web site that also has step by step testing procedures.

 

[boobie]

Re: 1972 Evinrude 100 hp starflite...ignition system issue?

It's sounds like somebody has converted it over to straight battery ignition which can be done on that mtr as long as it has breaker points.

 

[flamon]

Re: 1972 Evinrude 100 hp starflite...ignition system issue?

If it has been converted to battery ignition (which is what I suspected also), would the issues that I am having make sense?

I have ordered a new rectifier and will post my results.

 

[emdsapmgr]

Re: 1972 Evinrude 100 hp starflite...ignition system issue?

Post some pictures of the ignition components. My 72 would run fine when cold. After 15-20 minutes, it would quit. Wound up being a bad timing sensor. Weak ignition components tend to fail once the engine heats up to normal operating temps.

 

[Russell4]

Re: 1972 Evinrude 100 hp starflite...ignition system issue?

Had simular problem with motor it ended up being bad coil wire as engine wqarms up lack of contact and it can be speratic mine was Good luck