fast idle with new fuel pumps

[fastkenny]

i just replace all 4 fuel pumps on twin '88 150 yamaha 2 strokes.<br /><br />with the old pumps, both motors idled at 800 rpm, with new pumps, one is a 1000, the other at 900. since nothing else changed, should i assume timing is fine and adjust the idle screws? or should i check timing to be thorough (i know it's quick, but i don't have a timing light). it it common for idle rpm to rise after replacing pumps?<br /><br />also, i was concerned about possible lean condition (dirty carbs) due to a few backfires on initial starting. i attributed that to all the fogging oil in the carbs, since they started fine after running a while. would a fast idle be further indication that carbs are clean?<br /><br />thanks!

 

[rodbolt]

Re: fast idle with new fuel pumps

hello<br /> most likly the old pumps had been leaking some and instead of getting fixed the idle speed screw was adjusted to compensate. if at any time in a motors life the idle or air fuel has to be adjusted with no major changes in altitude something went wrong and its time to repair not adjust. same as an EFI motor. it either idles correctly or the dang thang is broke,fix it. fuel pumps cannot affect timing. if timing was correct when ya started its still correct. I see to many techs monkey with adjustments to compensate for their lack of knowledge, funny thing is its all written in mostly english and all ya have to do is read.<br /> check your starting procedure. its common to have a lean sneeze at cold start. especially if your starting them at idle. need to fire them off about 1500 rpm and bump the choke a few times for the first 60 seconds.

 

[fastkenny]

Re: fast idle with new fuel pumps

thanks rodbolt, that's what i was hoping to hear!<br /><br />after adjusting idle, all that's left this spring is to clean the remote oil tank filters then put it in the water.<br /><br />i figure i saved enough this spring to pay for 2 or 3 fillups thanks to the info and advice here!