choke solenoid works, but does nothing??

[boostin_7]

I cant get the electric choke to work properly on my '66 100hp johnson.
Ive been shutting it by hand for cold start, then racing back to the outboard to open it back up once the engine starts.
The solenoid moves its piston IN when i flick the choke switch on the dash, but it does nothing to open or shut the choke plates.
It almost seems to me that the natural position of the solenoid piston needs to be out heaps more than it is, which would keep the choke plates open. Then when i press the switch, & the piston pulls in, this would close the choke plate???? But im not sure if Im looking at this from the wrong perspective.
Here's a pic of the top, which Ive been using to adjust the plates manually?
I dont know which position it should be in for electric mode, but Im guessing its with the 'M' shaped part locked into the clip part, which would leave the choke plates open.

This is a pic of the solenoid at its resting/normal state (i.e 0v on it), then when its activated it pulls in that little bit but does nothing to move the choke.

Any help would be greatly appreciated,

Greg

 

[Chris1956]

Re: choke solenoid works, but does nothing??

Greg, I cannot see your pictures, for some reason. As the piston pulls into the solenoid it should pull the choke plates shut. The solenoid can sometimes be moved up and sown in the brass strap. Maybe yours needs to be lowered?

The manual choke lever sometimes has a center position, for electric choke useage, versus manually open or closed. See if you can set the lever there.

 

[boostin_7]

Re: choke solenoid works, but does nothing??

Hi Chris, Thanks for your reply.
I believe i have found the point the choke lever needs to be for electric useage. Its the spot where a moulded section fits into a clip so its position is held there. Also in this position the choke plates are alot easier to move by finger, so it makes sense it would be able to be moved by the solenoid.
Ive pulled out the solenoid, it retracts fine when 12v is put on it, but it doesnt have any resistance when out. Which means it only stays out a tiny amount due to the pressure from the choke plates on the spring, and beacuse of this when the solenoid goes in it has no effect on the choke.
Im thinking about heading down to an electronics store & buying another solenoid of similar specs to try, for 1/10th the price of a replacement unit.

 

[F_R]

Re: choke solenoid works, but does nothing??

First, you gotta understand that choke. It is an automatic choke, with an electric booster.

The automatic part is a bimetal spring heated by hot air coming through that steel tube when it runs.

The electric booster is the solenoid.

The automatic part does not have enough closing pressure for cold starts, that is why the solenoid is there.

The rotating part on top allows you to select "Choke off", "Automatic", and "Choke on". You should normally leave it in "Automatic" which is with the little clip in the detent.

With a cold motor, the automatic part will have the choke plates closed. When you activate the electric part, the solenoid plunger pulls in and the spring linkage slams the choke plates tight shut. When you get off the choke switch, the automatic part takes over, keeping the plates partly closed till it warms up. Then they should be fully open.

In addition to all that, the off-center condition of the plates on the shaft causes engine vacuum to pull the plates partly open when it starts to prevent over-choking and flooding.

The amount of choke closure during the warm-up stage can be adjusted by the little dial gizmo on top.

If everything is as it should be, it is a well working system.

BTW, the knob is missing off the top of your choke.

 

[boostin_7]

Re: choke solenoid works, but does nothing??

wow, thanks so much mate. Just the explanation i needed, i couldnt find out anywhere how it actually worked, so i was guessing