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Cummins PT Pump


bullhusk
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My 361 Brockway has a Super 250 now the Cummins book says it came with 2 hp ratings 250 an 270 mine is a 250, now is it pos. to turn the PT pump up without takin it off of the motor? If so can anyone out there help me out on how I can put more fuel to this old Husky? I just can't take it on the hills anymore! I know it's runnin lean cause it don't smoke, I mean It looks like it's runnin on LNG! I did an in frame on it last year and the pump looks new

Thanks

BULLHUSK

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  • 2 weeks later...

Yes... where the throttle linkage is there is a tin cover behind it.... remove the throttle linkage and the tin cover behind the cover you will see an allen head adjuster screw with a jam nut .... turn it an 1/8th at a time but make sure you put a vice grip on the throttle shaft or it may start WOT ... its better with 2 people .... with the vice grip you can control the throttle till you get the power you want .... only adjust the screw with it not running..... oh and replace your fuel line from the tank to the filter ... they go bad internally and may be collapsing restricting fuel flow and volume ... lines are only good 5-8 years even tho they look good on the outside.

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Your going to get many different ways of setting it so pick what you want to do. First thing is get a liquid filled 300 lb pressure gauge. Connect a 8 ft 3 4 hose to it and tie it to your wiper arm then connect other end to the 1/8 plug on the fuel pump shut down valve.Drive it loaded or load it with the brakes and catch a hill and at 2100 rpm slowly pull it down and watch your max fuel pressure. It will go up and down with your foot or rpm or the load you put the engine at,record that and then go home and pull the rear 4 bolt cover on the pump. Remover the snap ring and be carefull and don't drop the parts that is in there. Pull them out slow and then remove the fuel button or rear name to cunmins parts man is fuel idle plunger. There is a # on it and you will have to try some different sizes to raise your fuel pressure. Raise it by dropping the # on the button. Don't raise the pressure no more than 20 psi. I would go 15 because this engine has no turbo.I would say go 2 sizes lower or 2 # lower than what you take out.The little screw in there is your idle stting screw. The large shims in there are your top rpm shims.If you go more than 20 psi you stand a change of melting pistons.If you post a photo of the pump I can give you some more pointers

glenn akers

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Yes... where the throttle linkage is there is a tin cover behind it.... remove the throttle linkage and the tin cover behind the cover you will see an allen head adjuster screw with a jam nut .... turn it an 1/8th at a time but make sure you put a vice grip on the throttle shaft or it may start WOT ... its better with 2 people .... with the vice grip you can control the throttle till you get the power you want .... only adjust the screw with it not running..... oh and replace your fuel line from the tank to the filter ... they go bad internally and may be collapsing restricting fuel flow and volume ... lines are only good 5-8 years even tho they look good on the outside.

What he was talking about on his engine is a engine that is not turboed. Or it did not from factory so it will not have a AFC fuel pump on it meaning there is no tin cover or adjusting screw under there. That screw you are talking about don't set power but only sets the no air setting . Smoke screw if you want to call it. It gives you more or less throttle response. Good advive on the inlet fuel hose.

glenn akers

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Your going to get many different ways of setting it so pick what you want to do. First thing is get a liquid filled 300 lb pressure gauge. Connect a 8 ft 3 4 hose to it and tie it to your wiper arm then connect other end to the 1/8 plug on the fuel pump shut down valve.Drive it loaded or load it with the brakes and catch a hill and at 2100 rpm slowly pull it down and watch your max fuel pressure. It will go up and down with your foot or rpm or the load you put the engine at,record that and then go home and pull the rear 4 bolt cover on the pump. Remover the snap ring and be carefull and don't drop the parts that is in there. Pull them out slow and then remove the fuel button or rear name to cunmins parts man is fuel idle plunger. There is a # on it and you will have to try some different sizes to raise your fuel pressure. Raise it by dropping the # on the button. Don't raise the pressure no more than 20 psi. I would go 15 because this engine has no turbo.I would say go 2 sizes lower or 2 # lower than what you take out.The little screw in there is your idle stting screw. The large shims in there are your top rpm shims.If you go more than 20 psi you stand a change of melting pistons.If you post a photo of the pump I can give you some more pointers

Thanks I will get you a pic. And I am going to change that line cause it looks original !

BULLHUSK

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Its been a long time since I turned the fuel up on a 250 cummins, but I put a bigger button ( smaller number like 45 compared to a 47). then there is a snap ring that holds the throttle shaft in there, pull the throttle shaft, there is an allen screw in the end, there are little brass shims in there that opens a little hole in the shaft. I don't know if it is the fuel pressure or not but I thought it helped more than the button change. Ron

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The throttle shaft needs to be only half open and yes more shims added the more the opening is open.But that is for fine tunning like if the 45 buttons gets you 178 psi and the specs is 182 then you can add a shim or two and fine tune to the spec. If your doing one for a cummins under warranty it needs to be on specs for less complains from the management.

glenn akers

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