High Idle adjustment/full throttle stop?
Thread Starter
|
Senior User
Joined: Feb 2015
Posts: 194
Likes: 0
High Idle adjustment/full throttle stop?
What is the purpose of limiting throttle at the WO position? Have been researching but finding conflicting info. I don't need to turn more RPMs but having a touch more fuel up top would be nice. The adjustment i speak is a small nut and bolt on the back side of the throttle arm.
Senior User
Joined: Aug 2012
Posts: 152
Likes: 0
From: citrus heights California
From experience and shared knowledge, they were designed to be ran up to the throttle stop for hours. My old mud truck often found it for minutes at a time in 4lo. Never had an issue, aside from the mileage. With that being said. What nut for fuel up top are you referring too??
Postmaster
Joined: Dec 2011
Posts: 3,860
Likes: 7
Adjusting the throttle stop won't do much of anything. It's mostly there to protect the lever from going too far and getting stuck. Your RPM is governed inside the pump itself; you can't adjust it from outside.
Also, you drop both air and fuel pressure once you go much above 2000; if you want to actually get anything out of the higher revs, you really need a turbo... and even with that, an improved pump, and a governor that will allow for 4K+ revs, you'll still peak out in HP in the 2800-3K range.
Running 3600RPM governed max won't hurt the engine, but there isn't a ton to be gained by messing with the governor.
You can turn the overall fuel limit screw up, but you'll quickly run out of air and start seeing black smoke. Once that happens, you won't be getting /any/ more power without more air(i.e. you need a turbo).
Also, you drop both air and fuel pressure once you go much above 2000; if you want to actually get anything out of the higher revs, you really need a turbo... and even with that, an improved pump, and a governor that will allow for 4K+ revs, you'll still peak out in HP in the 2800-3K range.
Running 3600RPM governed max won't hurt the engine, but there isn't a ton to be gained by messing with the governor.
You can turn the overall fuel limit screw up, but you'll quickly run out of air and start seeing black smoke. Once that happens, you won't be getting /any/ more power without more air(i.e. you need a turbo).
Thread Starter
|
Senior User
Joined: Feb 2015
Posts: 194
Likes: 0
Adjusting the throttle stop won't do much of anything. It's mostly there to protect the lever from going too far and getting stuck. Your RPM is governed inside the pump itself; you can't adjust it from outside.
Also, you drop both air and fuel pressure once you go much above 2000; if you want to actually get anything out of the higher revs, you really need a turbo... and even with that, an improved pump, and a governor that will allow for 4K+ revs, you'll still peak out in HP in the 2800-3K range.
Running 3600RPM governed max won't hurt the engine, but there isn't a ton to be gained by messing with the governor.
You can turn the overall fuel limit screw up, but you'll quickly run out of air and start seeing black smoke. Once that happens, you won't be getting /any/ more power without more air(i.e. you need a turbo).
Also, you drop both air and fuel pressure once you go much above 2000; if you want to actually get anything out of the higher revs, you really need a turbo... and even with that, an improved pump, and a governor that will allow for 4K+ revs, you'll still peak out in HP in the 2800-3K range.
Running 3600RPM governed max won't hurt the engine, but there isn't a ton to be gained by messing with the governor.
You can turn the overall fuel limit screw up, but you'll quickly run out of air and start seeing black smoke. Once that happens, you won't be getting /any/ more power without more air(i.e. you need a turbo).
Back to the question at hand, i had seen that the less the nut/bolt is threaded , the more the gov spring compresses when hitting the throttle, which in effect raises max rpm, but in theory would also raise fuel cutoff?
Postmaster
Joined: Dec 2011
Posts: 3,860
Likes: 7
I'm not sure exactly what you have to do to the governor to make it defuel at a higher RPM. I believe you have to modify/replace the governor spring; I recall being told that you could shim it with a washer to adjust it. Remember, this is the large stiff spring inside the IP, in the governor assembly at the top.
Before messing with that, I'd try screwing with timing. Keep advancing it in small increments as long as you are getting more power / it's feeling better.
At this point, you can probably consider the IP "shot" for the purposes of screwing with it; so you might as well just adjust it as best you can until you get an improved one.
Being as your timing curve will be different than when new, you can't use the timing method that is suggested; you are basically doing it by ear at this point. Once you get things close, you can try messing with the position of the mechanical advance cam and see if you can get any better. Just take pictures/measurements of where everything is now, so you can always go back if things get worse.
Before messing with that, I'd try screwing with timing. Keep advancing it in small increments as long as you are getting more power / it's feeling better.
At this point, you can probably consider the IP "shot" for the purposes of screwing with it; so you might as well just adjust it as best you can until you get an improved one.
Being as your timing curve will be different than when new, you can't use the timing method that is suggested; you are basically doing it by ear at this point. Once you get things close, you can try messing with the position of the mechanical advance cam and see if you can get any better. Just take pictures/measurements of where everything is now, so you can always go back if things get worse.
Thread
Thread Starter
Forum
Replies
Last Post
belshe92
1973 - 1979 F-100 & Larger F-Series Trucks
16
Aug 29, 2018 12:43 PM
jeffnwm
1999 - 2003 7.3L Power Stroke Diesel
6
Mar 15, 2009 08:51 PM
FORD MEGA CAB!!!
Pre-Power Stroke Diesel (7.3L IDI & 6.9L)
4
Aug 20, 2008 10:35 PM
pontichev
Pre-Power Stroke Diesel (7.3L IDI & 6.9L)
8
Aug 8, 2008 09:49 AM
