3447 CARB REBUILD

[MIKESPOLARA]

I had my 3447 max wedge carbs rebuilt and found out some strange stuff. When I picked them up the fellow pointed out a couple of issues. One was someone installed an incorrect fuel inlet fitting on one carb. The fitting is entirely wrong and I should have had a massive fuel leak but I never did. The fitting was for the inverted flare type on the male end to carb. No idea why it didn't leak. But the big issue he pointed out was I wasn't getting wide open throttle. The linkage would hit on the idle screw and the butterflies opened about 90% on the primary and maybe 40% on the sec. I had to grind a little off the linkage arm where it hit the idle screw. Let's see if I notice any performance gain!

 

[Geoff 2]

Sounds like something needed to bent, not ground off......

 

[MIKESPOLARA]

Sounds like something needed to bent, not ground off......

Nope. You would have to see it to fully understand that it was not a bent issue what so ever. I was once told to adjust the idle by using the large air adjust that these carbs have, tried it once and I couldn't do so. I've seen pics of other 3447 carbs that do not have the idle screw installed. So I don't know what is correct but I solved the issue of the linkage hitting the screws.

 

[MIKESPOLARA]

Sounds like something needed to bent, not ground off......

Here's what I was told 4 years ago, didn't seem to work for me then I noticed there were idle adjust screws and went that route. Now I find out they stop the throttle from fully opening. So now I believe the idle air adjust on these carbs is correct. Look at post # 5: MAX WEDGE IDLE ADJUSTMENT

 

[MIKESPOLARA]

So I got it all back together. After a little more research I'm convinced these carbs used the large center screw to adjust the idle speed. It was difficult but after screwing the large center screw outward about 5 full turns it would idle. The carbs became very noisy with air sucking, almost whistling. I was uncomfortable with that many turns out. But my problem is the torque convertor is too tight and I have to have the idle quite high to be able to put in gear and not die out. Especially when going into reverse. With the idle so high I'm out of the idle circuit. I finally gave up and went back to using the idle screws. For what it's worth I have no idea what cam is in the engine. It does run better, I no longer smell like gas working on the engine. I made sure they replaced the well plugs and I think that solved the gas disappearing from the carbs in a couple of days.

 

[Geoff 2]

The big, brass screw in the front centre of the carb is for idle speed adjustment. Many did not have a conventional adj screw on the drivers side, although some models had the boss on the side of the body, allowing it to be drilled/tapped to take a conventional idle speed screw.
Another tip off is the pri throttle blades. They were thick-er alum, with steps machined in them.
These carbs will be hard to adjust for low vacuum situations without a positive idle stop. You may also need bypass air holes in the t/blades to restore the t-slot/idle relationship.