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Discussion Starter · #1 ·
Usually its the other way around, but i actually want to decrease fuel usage and power. the 7710 I bought was turned up and has lots of power, and lots of black smoke and fuel comsumption. I know I have to get behind the governer cover on the back of the pump, but not sure what I will find there or what to do (lock/jam nut on rack linkage?) never touched one before. I have a picture of what the pump is, this is a different one from my own, but exactly the same pump, motorpar. thanks
 

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:wgtt:

User JD110 should be able to help you with that, he usually checks in later in the evening.
 

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On the Motorpal pump, there are three adjusting screws behind that cover. Loosen the jam nut on the largest one and back out the screw to lessen the fuel delivery. The only problem is you won't know how much you are changing power without the use of a dyno. Do you know where your power is now? These pumps seem to vary greatly. Sometimes 1/4 turn makes 20 hp difference and other times it might take 2 or 3 full turns. Be sure to keep track of how much you turn it so you can put it back if you don't like the result. Sometimes when an engine is turned up, timing is changed also and sometimes injectors are changed, so turning fuel screw may not give you the result you want.
 

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Discussion Starter · #4 ·
Thanks jd110. I will probably try 1/4 - 1/2 turn at a time and use it on the manure spreader and test it going up hills and guage my speed and rpm's. My father has a 7710 with a denso pump that has not been touched, totally stock, so that's what I can test against. the pump and maybe the injectors make the tractors sound a bit different, but the power should be still be similar if they were both stock. I guess if I want to dyno, the local jd dealer has one I could use. that's the most accurate way I realize.

I dont think anything else is changed as far as injectors and timing is concerened. the 6 screws on the pump cover, the paint has been broken, but the timing cover/pump bolts/front cover the paint on the bolts indicates it has not had a wernch on it. this also goes for the injector flanges etc. good point though, you never know.

Im hoping this may extend the life of the drivetrain ( using the powershift at full load going up hills, less hp, less strain?) as well as save some fuel, dont really need more than 135hp for our applications. thanks again.
 

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On the Motorpal pump, there are three adjusting screws behind that cover. Loosen the jam nut on the largest one and back out the screw to lessen the fuel delivery. The only problem is you won't know how much you are changing power without the use of a dyno. Do you know where your power is now? These pumps seem to vary greatly. Sometimes 1/4 turn makes 20 hp difference and other times it might take 2 or 3 full turns. Be sure to keep track of how much you turn it so you can put it back if you don't like the result. Sometimes when an engine is turned up, timing is changed also and sometimes injectors are changed, so turning fuel screw may not give you the result you want.
I know this is an old thread but I wondered about a little more clarification. There is a noticeably smaller screw off to the side and 2 larger screws. Is the fuel screw the lower one inside the opening on the back of the pump or the upper one right into the casting?
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Discussion Starter · #7 ·
I believe its the lower screw in the center but maybe jd110 should confirm that. . As far as I know it adjusts the position of the rack, giving more or less fuel depending on which way you turn it.
 

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I believe its the lower screw in the center but maybe jd110 should confirm that. . As far as I know it adjusts the position of the rack, giving more or less fuel depending on which way you turn it.
Did you ever get your 77 set where you wanted it? I know this is 9 years ago just curious.
 

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The one at the very bottom of photo that is only partially visible in photo is the correct one.
 

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The one at the very bottom of photo that is only partially visible in photo is the correct one.
Thanks. Just for my curiosity because there is so little information about these pumps availible. What do the other two adjusters do? The tractor pullers I talked to had the opinion that I should throw the motorpal away so that wasn't overly helpful.
 
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