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I realize this posting is from a few years back, but I found it to be a great amount of information. Since my carb knob was busted, I figured I’d post a link to a site that I uploaded a 3d printable version to. If you have any questions about it, let me know.
https://www.thingiverse.com/thing:4547373
Hopefully someone finds this handy in the future as it’s a pain to try and adjust the mixture screw and work the choke by hand. The knob does both at the same time.
Finding these posts were almost as good as hitting the lottery. I’ve recently been cleaning up and getting the nerve to start my 4425. Someone gave this to my father, who gave it to me. Between the two of us, it has probably been sitting for 35 or more years. I used it about 20 some years ago on a square stern canoe, but that’s been it. The only part that is missing is the carb knob and linkage to choke on carb. Hopefully I can get to the 3d printable knob posted by pjmcardle. I would really like to see some detail of how it is supposed to link up to the carb, if anyone can provide.
Thanks
John
1 user thanked author for this post.
Evinrude put out 2 Service Bulletins between 1949-1953 pertaining to the 4425 Sportsman. Evinrude Service Bulletin Number 53 concerned incorrect polarity of the magnet rotor in the magneto. Evinrude Service Bulletin Number 113 concerned an improved reed for the carb. If anyone has these 2 bulletins, I’d like to know what exactly they said.
The 4425 used spark plug Champion J6J or Autolite A3X gapped at .030"
Points gap is .020"
The float should extend above the float bowl rim by 1/32" when the bowl is full of fuel.
Condenser rating was .2 mfd.
Flywheel nut torque is 25 ft lb.
Note the screen in the carb bowl where the inlet elbow screws in.
Low speed needle is normally 3/4 turn out from closed.The attached lower unit picture shows the sequence of disassembly numerically. Begin with screw number 1 per the instructions,(only if you must).
Attachments:
From an AI search for the 1948–1952 Evinrude 1.5 HP Sportsman (<mark class=”HxTRcb” data-sfc-cb=”” data-complete=”true” data-sae=””>Model 4425</mark>), Service Bulletin 113 identifies the improved reed as part of a performance update for the carburetor. <button class=”rBl3me” tabindex=”0″ data-amic=”true” data-icl-uuid=”7faddb5a-f215-41d0-a007-6d01f719bc2f” aria-label=”View related links” data-wiz-attrbind=”disabled=bS5i1_i/C5gNJc;aria-label=bS5i1_i/bOjMyf;class=bS5i1_i/UpSNec” data-ved=”2ahUKEwiTy52Z4KSTAxUUG9AFHUk9FKsQye0OegYIAQgCEAI” data-hveid=”CAEIAhAC”></button>Part Details<button class=”rBl3me” tabindex=”0″ data-amic=”true” data-icl-uuid=”04ceb55d-afea-4724-be94-5a3b14cfb8ae” aria-label=”View related links” data-wiz-attrbind=”disabled=bS5i1_o/C5gNJc;aria-label=bS5i1_o/bOjMyf;class=bS5i1_o/UpSNec” data-ved=”2ahUKEwiTy52Z4KSTAxUUG9AFHUk9FKsQye0OegYIAQgDEAA” data-hveid=”CAEIAxAA”></button>- Improved Reed Part Number: 202476 (historically superseding the original 202159 reed).
- Reed Plate Assembly: If you are replacing the entire assembly associated with this update, the plate part number is often cited as 202477. <button class=”rBl3me” tabindex=”0″ data-amic=”true” data-icl-uuid=”cb9e5cd5-f2a8-432a-bfb6-d29a57444aeb” aria-label=”View related links” data-wiz-attrbind=”disabled=bS5i1_10/C5gNJc;aria-label=bS5i1_10/bOjMyf;class=bS5i1_10/UpSNec” data-ved=”2ahUKEwiTy52Z4KSTAxUUG9AFHUk9FKsQye0OegYIAQgEEAI” data-hveid=”CAEIBBAC”></button>
Why the Change?<button class=”rBl3me” tabindex=”0″ data-amic=”true” data-icl-uuid=”d5582765-59f3-4ec8-95db-a406ef727d74″ aria-label=”View related links” data-wiz-attrbind=”disabled=bS5i1_17/C5gNJc;aria-label=bS5i1_17/bOjMyf;class=bS5i1_17/UpSNec” data-ved=”2ahUKEwiTy52Z4KSTAxUUG9AFHUk9FKsQye0OegYIAQgFEAA” data-hveid=”CAEIBRAA”></button>The original brass reeds were prone to fatigue or improper sealing, which caused “blowby”. This led to hard starting and poor idling. The improved reed (Bulletin 113) used a slightly different material (stainless steel) to ensure a more reliable seal against the intake manifold. <button class=”rBl3me” tabindex=”0″ data-amic=”true” data-icl-uuid=”03131ac9-cc26-4e6d-b18c-ca938d2e1dec” aria-label=”View related links” data-wiz-attrbind=”disabled=bS5i1_1b/C5gNJc;aria-label=bS5i1_1b/bOjMyf;class=bS5i1_1b/UpSNec” data-ved=”2ahUKEwiTy52Z4KSTAxUUG9AFHUk9FKsQye0OegYIAQgGEAE” data-hveid=”CAEIBhAB”></button>Availability Note<button class=”rBl3me” tabindex=”0″ data-amic=”true” data-icl-uuid=”65882e3b-ac7f-4c5c-8526-66442c6eefd1″ aria-label=”View related links” data-wiz-attrbind=”disabled=bS5i1_1i/C5gNJc;aria-label=bS5i1_1i/bOjMyf;class=bS5i1_1i/UpSNec” data-ved=”2ahUKEwiTy52Z4KSTAxUUG9AFHUk9FKsQye0OegYIAQgHEAA” data-hveid=”CAEIBxAA”></button>These parts are considered NLA (No Longer Available) from original manufacturer stock.
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