Marvel-Schebler Carb in a PA-11 and J-3 with C-90

[Evan]

I'm happy with the Stromberg in my PA-11, but looking at TCDS A-691, I am confused about the different specifications for the C-90 engine if it's installed in the J3 vs the PA-11

In the TCDS under heading IV-Model J3C-65 the TCDS allows optional engines in 311C. 311 C (10) states C-90-8F with the comment "Carburetor heat system must be modified to provide required heat rise. Approved modification made by M. Mullis, York, South Carolina."

Specifically there is no mention of anything about which carburetor.

In the TCDS under heading VI-Model PA-11 the TCDS allows optional engines in 311D. 311 D(5) states C-90-8F with the comment "Bendix-Stromberg carburetor, Continental Part No. 530726 and engine cooling baffles per Piper Dwg. 11258 Change E are required with this engine."

1) Why would the TCDS require the Stromberg in the PA-11 with the C-90-8F, but not in the J3C?
That's my main question. Is there some historical reason for this ? Any good reason for this requirement ? Typo ?

2) A secondary question, why hasn't anyone posted an old 337 which could serve as approved data for installing a MS Carb in a PA-11 ?

 

[bob turner]

 

[huston marlowe]

 

[Evan]

 

[bob turner]

 

[huston marlowe]

 

[ab0ngcd]

 

[reileyr]

 

[biplanespecialties]

 

[Evan]