Another Stromberg 97 jetting question !!!

I have installed my new English 97 Strombergs on my flat head V12. I started with the original ones which were 0.45 mains and 0.65 power valves. After driving 50 miles or so I pulled the plugs and they looked rich. I than decided to install a smaller main jet 0.43 and change the power valve to 0.69 . I have put in over 75 miles and pulled the plugs again to read them again they looked rich. Is the power valve going to a 0.69 could be making it to rich and maybe going back to a 0.65 or should I go down on the mains with 0.41 and leaving my 0.69 power valves in. Here in Phoenix we are at 1,600 feet above sea level. Let me know

Thanks for the help

Frenchy

 

What is rich to you..Color...The P.V. doesn't open till later. 0.69 is smaller and 0.43 is smaller..I believe I recommended using jet adjusters rather then swapping out jets..Put the stock .45 in and dial them in with the adjusters..EASY..
Duane..

 

Frenchy,
I'm no expert, but have several years experience with original, and the new Stromberg (English) 97s. Your jetting sounds on the money, as does the power valves. Keep in mind the PVs pass fuel (open) anytime the accelerator is pumped. The PVs are HELD open during wide open throttle by the pump shaft, but all PVs flow the same amount AT wide open throttle, just like Holley vacuum operated power valves.
Assuming ignition/timing is OK, and the floats are set right, and "float", I would try changing to hotter plugs, as I did. I went from NGK B6Ls to B4Ls and they read much cleaner. Todays gas does not color the plugs like it used to, one more thing to consider. IMO.
Bob

 

i also went hotter on my plugs with good results . went from champion 18 - 20's . still rich , but doesnt foul the plugs as b 4 ................ steve

 

Thank You everyone I hate to be a bother with this issue but I am just asking for some help. The plugs are very black and I use the Champion H10C. I will be trying NGK B4Ls and see the outcome. Duane Thank You for all the help you have given me. I will let everyone know. I do not foul plugs.

Thanks
Frenchy

 

if they are very rich , you will . nice car by the way ............... steve

ps: i have a new set of "69" PV's if anyone can use them ........................

 

Where can I find these plugs NGK B4Ls. I have called a couple of stores and no one has them.

Thanks !
Frenchy

 

Our local NAPA stores carry NGK plugs. They stock B6Ls, but had to order the hotter B4Ls.

 

Thanks Bob I will try a set of the NGK B4Ls and see . You have them on your flat head right!

Frenchy

 

Yes, I'm running B4Ls. I do not use Champs, and the last Autolite 216s I bought were made in China and had terrible quality, so I'm sticking with NGKs for now.