1977 70 hp evinrude

[mjames76]

I have a 70hp evinrude giving me starting problems. I tried to start it yesterday and I wasn't getting any fire at the plugs. I went out today and pulled out a plug hit the key and POW it had fire I put the plug in and it started right up. I started doing a few other things and came back an hour later and no fire again. I just got this engine to put on a boat I am rebuilding so it is new to me Compression seems good 123-125psi on all cylinders but intermittent fire is driving me crazy. Any ideas?

 

[F_R]

Re: 1977 70 hp evinrude

It has to be cranking at 300 rpm to have fire. Removing a plug lets it crank faster and make the difference.

Or there may be an intermittant problem with the kill circuit .

 

[tashasdaddy]

Re: 1977 70 hp evinrude

clean all the contacts. take them apart and clean, also check the black yellow wire, this is the kill wire, make sure it is not shorting to something. also could be the ingition switch. unplug the big red cannon plug, and jump the solenoid and see if you have fire. you will have to choke it to stop it.

 

[mjames76]

Re: 1977 70 hp evinrude

It has to be cranking at 300 rpm to have fire. Removing a plug lets it crank faster and make the difference.

Or there may be an intermittant problem with the kill circuit .

I have a hot battery on it and once it fires I can kill it and as long as I start it again in the next few minutes it starts fine but if I wait a while it wont. I have un hooked the kill switch wire on the power pack and it doesnt seem to make a diffrence.

 

[mjames76]

Re: 1977 70 hp evinrude

clean all the contacts. take them apart and clean, also check the black yellow wire, this is the kill wire, make sure it is not shorting to something. also could be the ingition switch. unplug the big red cannon plug, and jump the solenoid and see if you have fire. you will have to choke it to stop it.

I wondered about the ignition switch. Which contacts are you talking about in the control box or on the motor?