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mechmagcn

A Little More Fuel

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Hi all, I'm looking to turn a little more fuel to SuperDawg. Right now it is at factory specs with a EM6300R, the seal hadn't been broken. I want just a little more pulling power. This pump is one that I'm not familiar with. American Bosch, what to do for a little more fuel, no more RPMs. Thanks for any help.

Jeff

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undo the lock nuts on the rod (located the right side of the gov box when facing the side of the engine) and turn the rod a few flats(of the nut, ballpark 2-4 flats) then tighten them making shre the rod does not move. If I remember you want the rod to move towards the front of the truck to get more fuel. someone correct me if im wrong on the direction for more fuel.. now watch your boost and EGTs and make shure its not to much. also watch your wallet at the pump LOL :bmod1:

Trent

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:bmod1: Thanks Trent. I don't think I'll really have a problem with EGTs or boost, seeing as to how I'm only pulling a 16K 5er. I don't want to soot the trailer up, so I will only turn it up until I see some light smoke.

Jeff

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Edited by mechmagcn

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Yep towards the front of the truck....

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I Have never played with an injector pump. With that in mind I labeled the picture with what I think is the lock nuts and the adjustment rod. Is this correct? if not please let me know. Also what is the difference's between an American Bosch and a Robert Bosch? post-128-1178242281_thumb.jpg

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you have it labled correctly...

you back off the nut on the left. turn it out a few flats

then grab the rod and twist it untill the left nut makes contact with the bridge again.

then hold the rod steady and tighten the nut on the right.

the correct way would be to flow test the pump to see how far beyond spec it is but it will do the job and still be safe if you dont throw to much fuel at it. The RPM adjustment is under a plate at the bottom rear of the box.

Be safe and remember to count the turns of the nut or rod as you may need to reset it?

Not shure of the diffrence between american and robert bosch pumps?

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The Limmited experience I have with the american bosch is, the governor in the A B seems to be somewhat more responsive, or "more jumpy" in responce to stepping her down. also easier to make the RPM adjustment, without removing the pump. Just remove back round cover on pump and change the spring, to increase rpm's. Down side to this pump is it can run away easier. We had one on a 237 (84 MR) that would run away "rev unlimited" had to dump the clutch to pull her down. the last time it did it it was in neutral, couldn'd get her in gear, needless to say, we no longer have the truck. The flywheel exploded after about 4000 rpm, transmision fell off and truck started on fire..... believe it or not the engine held together and ran for about 5 minutes while the truck was engulfed in flames. I estimate she turned in excess of about 6000 rpm until it finnally burned a fuel line off. good testament to the bottum end!! :pat:

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Thanks Lmack, I have always wondered what screw everyone was talking about. My 350 4V runs good, and I dont plan on turning it up. But the added knowledge is good to have. Now I just need to find out which pump I have. The only tag on the pump says "Re manufactured by Mack" "model 300" I'm sure there is some cosmetic differences between the two. But I have no idea what they are.

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The Limmited experience I have with the american bosch is, the governor in the A B seems to be somewhat more responsive, or "more jumpy" in responce to stepping her down. also easier to make the RPM adjustment, without removing the pump. Just remove back round cover on pump and change the spring, to increase rpm's. Down side to this pump is it can run away easier. We had one on a 237 (84 MR) that would run away "rev unlimited" had to dump the clutch to pull her down. the last time it did it it was in neutral, couldn'd get her in gear, needless to say, we no longer have the truck. The flywheel exploded after about 4000 rpm, transmision fell off and truck started on fire..... believe it or not the engine held together and ran for about 5 minutes while the truck was engulfed in flames. I estimate she turned in excess of about 6000 rpm until it finnally burned a fuel line off. good testament to the bottum end!! :pat:

Always important to make sure your engine shutdown lever works. That and a backup fuel shutoff valve near the pump or tank.

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Yep,I've done that before on that 'ol 300 F-model.It actually does work better than the stick and chicken bone method,but a little dab'll do you or you can burn the top of the stack off! I mean,I've seen it done-I wouldn't tamper with the pump on a company vehicle-well,maybe just enough 'til the top of the stack turns a little blue,not enough to burn it plum off!

Edited by other dog

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LOL Sometimes I wonder if you really hurt a Mack motor by turning them up. My old truck would and will turn the whole side of the motor (turbo and manifold and pipe) orange on a hard pull. If you lugged it down on a hard pull and turned the bed lights off you could see flame out the pipe as well. When I overwound by running away...it dropped a valve. Well when i tire it down to put a head and piston on it the liners and pistons still looked like brand new(with the exception of the one with a chunk of valve in it...lol). In fact the numbers were still visible on the pistons. This was after 5 years of that much fuel.

Hard to kill a 2 valve Mack..lol. The bottom end wont break but they will break a valve if overwound far enough in my experience.

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also watch your wallet at the pump LOL :bmod1:

Trent

Turning the fuel up can get into your wallet, 3 flats netted me about 3/4 MPG less on a 2000 mile trip last week. But I will say that the dog pulls much better now.

Jeff

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I personallly would never run a robert bosch pump, way too easy to run away. I run a 350 2 valve here in kentucky hauling coal grossing out at 126,000 and we always turn the fuel up for the heavy loads and always get years of service with no problems on the engine. Just keep an eye on your smoke output and pryometer to make sure you haven't turned too much to the dog. Keep a check on coolant temperature also when pulled down loaded and makes sure it isn't running up there. I turned mine up a lil too much one day and had the coolant temp running a lil hot.

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I personallly would never run a robert bosch pump, way too easy to run away. I run a 350 2 valve here in kentucky hauling coal grossing out at 126,000 and we always turn the fuel up for the heavy loads and always get years of service with no problems on the engine. Just keep an eye on your smoke output and pryometer to make sure you haven't turned too much to the dog. Keep a check on coolant temperature also when pulled down loaded and makes sure it isn't running up there. I turned mine up a lil too much one day and had the coolant temp running a lil hot.

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