1967 100HP Johnson Exhaust/Autochoke Question

[exodave]

This is a V4TL-13 model. I notice on the back of the engine coming out of the rear cover are two fittings, as seen in the photo of the motor mid-disassembly.

When assembled, the top one goes to the autochoke on the carb. The bottom one wasn't connected to anything when I purchased the motor. The two are directly connected underneath via a flat tube suspended inside the void where exhaust from all cylinders meet. I just want to know if there is supposed to be something connected to the bottom fitting. I don't notice anything missing on the engine parts diagrams, and as far as I can tell the autochoke works OK. Is there a vacuum in the autochoke, pulling air in that way? If so, is it OK that it's pulling right from the back of the motor inside the cover?

 

[racerone]

Re: 1967 100HP Johnson Exhaust/Autochoke Question

No-- Nothing connects to the bottom fitting !--It works thusly.---The carburetor sucks air into the bottom fitting.--The air goes through the wee heat exhanger there.--As motor warms then hot air starts going to the carburetor.--The carburetor choke mechanism has a bimetallic element in it.--The hot air regulates spring tension on the choke flappers.---You can adjust that tension as well up top on the carburetor.--It also has a manual overide solenoid too.

 

[F_R]

Re: 1967 100HP Johnson Exhaust/Autochoke Question

An often asked question. People see those threads in the open fitting and figure surely something goes in there. Nope!

 

[exodave]

Re: 1967 100HP Johnson Exhaust/Autochoke Question

Thanks! This thing is just full of tricks. I see now that the threads are just what holds the heat exchange to the inside of the back cover, not a vacant fitting.