1973 50hp Evinrude

[brents]

I have a 73 Rude that runs great, I have had it for a little over a year. The last couple of times I have taken it out however it has been a hard start. After a little tinkering I found that if I pull the manual choke on the motor it starts right up. I never had to do this before, my control box has an electric choke switch on it that I always used. Is this a sign of anything aside from the electric choke switch? Also, when I use the electric choke it is still opening the choke at the motor.

Once it starts I don't have to choke it again unless it sits for over an hour or so.

Thanks for your help!!

 

[F_R]

Re: 1973 50hp Evinrude

Ok, now I have to ask you a couple of questions because there were so many choke system varients that I lose track.

The manual choke knob: Does it have three positions, in, out, and half way? If so, out is manual choke, in is choke off, and half way is automatic. It has to be in half way or automatic position in order for the electric choke to work. This probably is where your problem lies.

The electric choke: Has it ever been rewired? There was a service bulletin on that. As it was originally wired, when you turn the ignition key on (cold motor) the choke should automatically close part way. I am speaking of the choke plates on the carburetors here, not the manual knob. Then when you operate the choke switch, the choke plates slam tight shut. If it does not do that, you probably have a bad thermal switch, the item that determines whether or not to close them part way.

However, if it has been rewired, the thermal switch has been eliminated and the choke plates do not do the partial closing thing when you turn the key on. But they do slam tight shut when you operate the switch.

But check the knob....pulled half way out is correct.

 

[jay_merrill]

Re: 1973 50hp Evinrude

Also, if the thermal choke system has been disconnected per the service bulletin, but the appropriate terminals on the terminal block have not been jumped, you will only get half actuation of the choke butterfly when you use the electric choke switch at the control box or dash. By making the jump, voltage is supplied to both windings in the choke solenoid when you use the forward switch.

 

[F_R]

Re: 1973 50hp Evinrude

That's true. That's all part of the service bulletin. I guess with all my explaining I got tired too soon.

 

[brents]

Re: 1973 50hp Evinrude

Thanks FR/Jay. What I found was when I close the manual choke at the motor it is closing to far. Although I am hearing the choke actuate when I use the electric, it is not opening the valve. I have to be more careful about closing the manual choke on my motor to ensure it doesn't push to far in. Weird enough, but seems to have fixed the problem.