Stalls when I put it in gear 727 TF

R

Ruper

Member
Well I rebuilt the carb 1850 4barrel, running great no misses not popping. Problem being when I put it in drive or reverse, it stalls out. I pushed the timing around but still having the stall out issue.

Curb idle is 700, and I adjusted it up, but still no help?

Is this a torque converter problem or tranny, possibly bands too tight. Scout II has not run in a while, but it was adjusted band wise good when it went it was put up. Planning on changing out the tranny oil, and checking all the bands, but really looking for some clues on what else to check and or replace.
 
Vaccum port on back of carb open?

Had similar issue years ago. Only to find out that there is a port on the back of the carb - 3/8" I think. I have seen a fitting there hooked up with a hose routed to the valve cover vent tube/pcv valve. If it's pre-smog then just install a set screw in there to plug it up
 
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I too highly doubt this issue is transmission related. Like scooter, I suspect a vacuum leak which is too much for the engine to overcome when a load is introduced.
 
Also, IH w/auto trans; engine idle speed is set with the engine warmed up and the transmission in drive.
 
1975ih200 said:
also, IH w/auto trans; engine idle speed is set with the engine warmed up and the transmission in drive.
Click to expand...

This is true. Ruper, since your engine stalls out when you put it in gear, setting the idle in this manner will be problematic. It is perfectly acceptable to set the idle speed in park also. You simply figure in the approximate rpm drop resulting from gear engagement which is roughly 125 rpms. For example, if your in gear target is 625 rpms, add 125 to that for an idle speed of @ 750 rpms in park.
 
Thanks for the input. I'll try these and if things still go wrong I'll do compression and leak down checks in case there is a stuck or blocked valve. While I'm in there I'll check valve adjustments. Going to check all vacuum lines but I know they are all plugged on the carb and believe them to be routed properly.

At this point I do not have the pcv valve hooked up yet, could this be contributing to the blue smoke I'm getting? Just trying to see if anyone has history about that issue. I'm pretty mechanically inclined but history in the 4 banger area of scouts. My 800 runs like a top but the 8v is giving me a headache.

Also I have a spread bore with a Holley square bore carb using that adapter. I had two chooses go with the adapter insert that was open or use a 4 hole adapter insert. I chose the open square bore insert, could this be a problem?

I wouldn't think so but just asking.
 
That last part about the square bore adapter on a spread bore manifold is something to check. There could easily be a vacuum leak here. Spray some wd-40 or flammable carb cleaner around the base of the carb and the adapters while the engine is idling. If the rpms increase, you've found your leak. Also, what's the condition of this square bore carb? Did it run well on another truck previously? Just trying to eliminate all the variables.
Btw, if the thing runs ok otherwise, I really doubt you have bad valves, or dead cylinders. Can you get your hands on a known good q-jet? Even if you borrowed one, it would fit the manifold properly (with the right gasket), and you could drop it in gear to see the difference at idle.
 
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You might want to buy a vacuum gauge and tell us how many inches of vacuum you have at idle. They are real handy for diagnosing all kinds of problems.

Also you say there is no pcv valve, it is an important part of the fuel system. The pcv valve allows a controlled amount of air/crankcase gasses into the manifold. So not having the valve in the system just might be part of the problem.
 
ruper said:
thanks for the input. I'll try these and if things still go wrong I'll do compression and leak down checks in case there is a stuck or blocked valve. While I'm in there I'll check valve adjustments. Going to check all vacuum lines but I know they are all plugged on the carb and believe them to be routed properly.

At this point I do not have the pcv valve hooked up yet, could this be contributing to the blue smoke I'm getting? Just trying to see if anyone has history about that issue. I'm pretty mechanically inclined but history in the 4 banger area of scouts. My 800 runs like a top but the 8v is giving me a headache.

Also I have a spread bore with a Holley square bore carb using that adapter. I had two chooses go with the adapter insert that was open or use a 4 hole adapter insert. I chose the open square bore insert, could this be a problem?

I wouldn't think so but just asking.
Click to expand...

The principles of internal combustion are the same for 4 cylinders or 8. A functioning pcv system is necessary in either case. I'm also skeptical of the open hole adapter you're using. Running a carb on an intake that it was never meant to fit is likely to be a constant uphill battle for you.
 
Thanks for the replys. Here's what the problem was, a broken intake valve spring was causing the vaccuum to go all over the place and obviously not hold vacuum under load.

I fixed the valve spring and it runs better. I am currently trying to set the kickdown since the shifting is irratic and I had recently changed to the lokar cable on the Holley 4150. The engine is holding power under a load better but still not optimal a 1-2 minutes in drive with the brake held down until it cuts out.

I have bumped up the jets to 69' but I think its a little Rich now changed the jets from 64's due to now having all 8 cylinders but I think it is now too Rich. Still takes a while to be able to open the choke lever open full while warming up.
 
I guess I stand corrected on the valve thing! Not at all what I expected. Good you found that issue. Sounds like the carb is still not your friend yet.
Let us know what happens.
 
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