Jellybean Posted August 24, 2014 Share Posted August 24, 2014 Can some one tell me why my 1988 em300L will only turn 1600 rpms. When I adjust the throttle stop it will shut the fuel completely down. The previous owner must have fixed it to only run about 58 mph. I think it needs to run about 1750 to run 65mph. Quote Link to comment Share on other sites More sharing options...
j_martell Posted August 24, 2014 Share Posted August 24, 2014 I think:The "M" in EM6-300 stands for Maxidyne, which means they will pull from around 1000rpm for use with the straight 5speed tranny and the "L" indicates a low speed motor,.lower governed max rpm....witch to me seem like contradictions. What transmission and rears are currently equipped?I also thought that older maxidynes were set with operating range from 1000-1800+ for the maxitorq transmissions....i have been wrong beforeSomewhere here, if you search, there is a thread with alot of the older engine codes and their meanings.....Someone who knows what they're talking about will be along to help shortly..... Quote Lack of planning on your part does not constitute an emergency on my part.... Link to comment Share on other sites More sharing options...
pmolitor Posted August 25, 2014 Share Posted August 25, 2014 I had that motor in my 90 ch. There is a governor on it. If I remember right your peak hp is at 1750 rpm. You can remove the governor, but the peak hp will remain the same. Search the site for em6300l. There is some info on it. Quote Link to comment Share on other sites More sharing options...
Solution b61mack Posted August 25, 2014 Solution Share Posted August 25, 2014 A friend of mine that ran a Mack dealership told me how to turn the RPM up on a 88 R Model with the 1800 RPM Maxidyne with the 6 speed air shift 5.55 Mack rears. I don't know if it was the right way or not but it worked. now turns 2100 and downshifts at 1200-1300. there is a plug on the backside of the pump ( kinda hard to get to ) that you take out maybe 22 mm , have someone turn the engine over while you look in the hole and you will see a slot with a pin in the center, use a long flat screwdriver push it down and turn clockwise about 5-6 turns to start with then you have to turn the engine over and do the other side of the governor( 1/2 way around make sure you turn both sides the same amount ). I don't know if it is good on the 4 valve heads to be turning 2100 - 2300 or not, this was a farm semi and worked good. someone on here should be able to tell you the long term effects on a 4 valve head. Quote Link to comment Share on other sites More sharing options...
masterwelder Posted August 25, 2014 Share Posted August 25, 2014 1600 is to low even for a maxidyne. Are you saying even with no load it will only turn 1600? Mine will rev up to 2100- no load but will pull to 1750 then start to cut back the power. You may have govener trouble if you all ready verified you're getting wide open throttle via the linkage. Quote Link to comment Share on other sites More sharing options...
Jellybean Posted August 27, 2014 Author Share Posted August 27, 2014 This truck has a 7 speed trans (2070). I am looking looking in to these governor issues now. Thank you Quote Link to comment Share on other sites More sharing options...
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