Choke plates open when cranking

[WizardIII]

Hello all.
First, I really appreciate this forum as it has helped answer many questions. I'm sure this issue has been covered but I can't seem to find the right combination of words when searching and now I have gray stuff coming out my ears.
I have a 1977 85hp Evinrude (85793) that has been gone over quite well. The carbs were rebuilt a while back but I have kits to do again if needed. I'm having the infamous 'cold start' problem but I think I've tracked it down. When I use the manual choke it usually starts up fairly quickly. I took the air silencer cover off and when I use the electric choke button the plates do snap closed 100% but when I start cranking they open up.....meaning they don't stay closed while cranking. Any ideas?
I have the OEM owner & service manuals but nothing there that I can see. I'm guessing it's what I can (or can't) see that is my problem.
Thanks for any help,
Steve

 

[Lone Duck]

Re: Choke plates open when cranking

Hello all.
First, I really appreciate this forum as it has helped answer many questions. I'm sure this issue has been covered but I can't seem to find the right combination of words when searching and now I have gray stuff coming out my ears.
I have a 1977 85hp Evinrude (85793) that has been gone over quite well. The carbs were rebuilt a while back but I have kits to do again if needed. I'm having the infamous 'cold start' problem but I think I've tracked it down. When I use the manual choke it usually starts up fairly quickly. I took the air silencer cover off and when I use the electric choke button the plates do snap closed 100% but when I start cranking they open up.....meaning they don't stay closed while cranking. Any ideas?
I have the OEM owner & service manuals but nothing there that I can see. I'm guessing it's what I can (or can't) see that is my problem.
Thanks for any help,
Steve

One guess is that your starter circuit is drawing to much power. Take a wire with alligator clips long enough to reach from power on your hot side of solenoid to the terminal on your choke it should snap shut. then turn over engine. if the choke stays closed, then it is your choke button circuit . If they come open, then i would be checking your starter draw and batt voltage under load.

 

[WizardIII]

Re: Choke plates open when cranking

That sounds like a good guess LD. I was just starting to entertain the idea of a weak(?) solenoid but it didn't make much sense. However, not enough energy to hold the solenoid due to current draw does make sense. I am using my older twin lever controls and wired the choke up to the button on the dash which may need looking into. Can't wait until it stops raining to give this a shot.
Thanks for the tip. Steve - WizardIII

 

[ondarvr]

Re: Choke plates open when cranking

Is there a spring between the solenoid and choke on this model, there should be an adjustment for it if there is. The spring may be too weak to hold the plates shut. I had 2 motors from that era and they both had springs.

 

[WizardIII]

Re: Choke plates open when cranking

Well, in my parts catalogue there is a spring that goes under the plunger that I ***-u-me was to help open the plates after start up. It wasn't there when I went through the motor so I replaced it (OEM). I can't see any other way to connect it....do I have this wrong?
Thanks

 

[ondarvr]

Re: Choke plates open when cranking

I still have one of the motors, I'll go look at it.

 

[ondarvr]

Re: Choke plates open when cranking

My V6 doesn't have a spring between the solenoid and the carb, the 50 does. Yours would be more like the V6.

On the V6 it snaps shut and stays there.

 

[WizardIII]

Re: Choke plates open when cranking

Thanks for checking ondarvr. Could you be more specific about the spring 'between the solenoid and choke'. My exploded view seems to show a spring underneath the plunger inside the solenoid which is where I put it. In the meantime I will pursue lone duck's idea as soon as the weather clears.
tnx agn, Steve

 

[daselbee]

Re: Choke plates open when cranking

Also possible that your ignition switch is bad. In other words, the +12 v on the purple/white wire goes away when key is turned all the way to the "start position", but is present when the key is in "run position".

 

[F_R]

Re: Choke plates open when cranking

Also possible that your ignition switch is bad. In other words, the +12 v on the purple/white wire goes away when key is turned all the way to the "start position", but is present when the key is in "run position".

My thoughts exactly. Check the voltage at the choke solenoid while cranking. I'll bet you have a bad key switch.

 

[ondarvr]

Re: Choke plates open when cranking

I use a separate toggle switch for the choke on my V6.

 

[WizardIII]

Re: Choke plates open when cranking

Got out in the crappy weather and did a quick check as LD suggested. Jumped a wire to choke solenoid and the plates stayed closed when cranking. Progress!
Thanks daselbee & F_R for your thoughts about the ignition switch also. I don't doubt that could be part or all of the problem as I am using the original but do have a spare I can swap out.
It will be a while before I can open up the control panel and work on it but I feel confident you all have helped put me in the right direction.
Thanks so much, Steve

 

[bigdaddy63]

Re: Choke plates open when cranking

I am glad to see this post. I have the same motor with the same problem.