Servicing choke on 1963 Big Twin

[baytonemus]

I'm in the process of cleaning and rebuilding the carburetor on my 1963 Evinrude 40 hp Big Twin. Fortunately, I've been able to locate some new parts that have long been "unavailable." I'm wondering about the choke, however. The manual says to inspect the diaphragm for cracks, but can you even buy a new diaphragm (OMC #378133)?

I'd like to disassemble and clean as much of this thing as I can and replace everything where it's reasonable to do so. I sure don't want to run the risk of damaging something delicate that I can't replace, though.

Also, it looks to me like there are no seals or packing on the throttle or choke shafts. There is quite a bit of free play in both. Is that normal? I'm a little more used to working on motorcycle carbs where the tolerances are very fine and have everything seal properly is critical.

Thanks.

 

[tmcalavy]

Re: Servicing choke on 1963 Big Twin

If you're referring to the solenoid that kicks the choke in and out, I wouldn't touch it other than to wipe it clean if it is working okay. There can be some play in the choke linkage, depending on the motor...again...as long as it works, leave it be.

 

[F_R]

Re: Servicing choke on 1963 Big Twin

No matter what you do with that hot-water choke, it won't be worth a hoot. Why not?? Because they weren't worth a hoot to begin with when brand new. Use the manual choke lever on the other side, and save yourself a lot of agrivation.

 

[tx1961whaler]

Re: Servicing choke on 1963 Big Twin

Diaphragm available here:
http://www.marineengine.com/newparts/part_details.php?pnum=OMC0378133&ptype=&Engine=&Model=

They greatly improved the hot water choke with the hot air choke system. Too bad two times zero is still zero.....that one didn't well either.

 

[baytonemus]

Re: Servicing choke on 1963 Big Twin

Part of the problem with this motor is that I don't know if anything works. It hasn't been running in a LONG time. I fiddled with it a little 15 years ago when it was given to me, but I didn't really make a serious attempt to get it going. This time I'm going to do it right.

Interesting info about the choke not being a very good design. Is the auto choke only engaged when the lever is set to "auto"? (I guess that would make sense...)

Thanks also for the link to the diaphragm. After posting I found a site that listed the whole auto choke assembly for $25 - new. Now I'm wondering if it's worth even bothering.

Thanks to all!

 

[tx1961whaler]

Re: Servicing choke on 1963 Big Twin

Lots of other thing to worry about before the choke...
Compression
Ignition System
Gearcase
Carb
Starter