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1986 Evinrude 70HP 2 stroke starting issue

R

richierni

New member
Hi folks, my usual starting routine is failing. I lift the (OMC control) fast idle lever high and the battery really struggles to turn the engine over (or crank as some people say). To the extent that there's no chance of it firing. I thought my battery was dying.

By chance, I tried to start it with the fast idle lever down, and it started to turn over normally! So I raised the lever once it was turning over and push in the key to give it some juice and then it fires and runs as well as it ever did.

This is recurring so not just a one off situation with a weak battery or something.

I don't understand why the battery would be able to turn it over fine with the lever down but not with it up. Is there some difference in terms of compression that makes it harder to crank?

Many thanks for any help!
 
Racerone is thinking along the lines that the timing is off making it a hard start and it very well may be.
I’d also be looking at the battery cables if you say the battery is good. Just because a battery is new does not mean much, load test it. Also a battery cable could look good but hiding inside it could be corroded.
 
Just to be clear though, I'm not saying it struggles to start. It only struggles to crank off the battery, and only when the fast idle lever is up.
It will crank with the fast idle lever down, and once it cranks it starts fine (I raise the lever once it starts cranking)

Does that still tally with your thoughts?
 
Don't I have to remove the flywheel to check that? Be very happy to hear it if I don't! Boat is in the water about 80 miles from home unfortunately, not so handy to work on.
 
Remove top sparkplug.---Use screwdiver to bring #1 to TDC.----Check timing pointer.----I am not saying that the key is sheared.----But it is such a simple check that costs nothing.
 
Maybe raise the fast idle lever, then disconnect the throttle cable at the motor. Lower the fast idle lever and try starting it.
If it starts ok - problem is in the box.
My memory is good but it is short! - I think on some control boxes there was an interlock switch that prevented starting the motor at high rpms.
It would not crank though.
I had a problem with a Merc where I timed the distributor to flywheel wrong (Merc used "0" as TDC). It started without the controls hooked up - but refused to start with the controls hooked up.

A sheared key would do the same thing.
My 2 cents

Allan
 
Of course I've been back three times since my last post and it's started perfectly. I will check for sheared key when I get around to it and report back. But for now I'm having too much fun boating! Thanks for all the ideas.
 
Just to be clear though, I'm not saying it struggles to start. It only struggles to crank off the battery, and only when the fast idle lever is up.
It will crank with the fast idle lever down, and once it cranks it starts fine (I raise the lever once it starts cranking)
Click to expand...

Interesting - here are my thoughts on it:

The starter engages when the solenoid is energized (has 12 volts on the "small" terminals).
(the solenoid is a relay).

When the key switch is turned to "START", voltage passes thru the key switch, thru the neutral switch, and the wiring,
and connectors back to the solenoid.
The neutral switch prevents starting the motor in forward or reverse.

In your case:
When the fast lever is down the solenoid receives full volts/amps and engages.
When the Lever is up - the solenoid is not receiving full volts/amps and cranking is difficult.

Something in the control box shifts, maybe the neutral switch is bad or loose, or not adjusted properly,
or a loose wire?

It will crank with the fast idle lever down. "(I raise the lever once it starts cranking)".
It takes more energy (volts/ amps) to engage the solenoid and the starter motor will draw more current to start spinning the flywheel.

Once it is cranking, it takes less energy (amps) to keep the solenoid engaged and the motor is already cranking.
With the lever up, there is enough energy to keep it running - but not enough to crank it from a dead start.

I suggest getting a copy of the Evinrude Service Manual, it is a must if you intend to do any maintenance.
Time to open up the control box - or maybe after winterizing?

Allan
 
That sounds very plausible, and might also explain it being a tad intermittent. Definitely something I'll take a look at once she's out of the water, which won't be long now actually, getting a bit nippy, thanks for the idea!
 
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