250 EFI MERC

arney

Recruit
Joined
May 21, 2006
Messages
4
Hey guys, I've been working on outboards for about 10 years now. But i've got one that's kicking my butt!!!! It's got a break neck holeshot and runs great up to about 5200 rpms and just goes flat right there!! All the cdm's check out;compression is good (heads cut at mad efi with 135 psi) the stator is new, boxes fresh back from rapair with no problems, all injector plugs on good,pickup sensor good, tps new and reeds new from mad efi,and ddt checks all other parameters ok!! Timing is right on the money at wot on the ddt.Fuel pressure is 38 psi. I'm lost!!!!! This motor ( 1998 250 efi 3.0 ltre) is on a 20 foot ranger 1995 (487 vs) with a 27 pitch laserII prop on it. But even if i trim it up almost out of the water it still won't pick up rpms! Injector problems??????? Any input will be greatly appreaciated!!!!! <br /> :eek: :confused:
 

jashou2003

Cadet
Joined
May 21, 2006
Messages
9
Re: 250 EFI MERC

Have you tried adjustments on the throttle cable/linkage. Maybe ever dropping to a lower pitch of prop. I have 21 Mirage Plus on mine the holeshot is a hard launch but not that much of a neck breaker but it plains out quick & gets those twin Merc's up to around 5750-5900 RPM's. Depending on water condition & trimmed up high as well. Good luck...
 

arney

Recruit
Joined
May 21, 2006
Messages
4
Re: 250 EFI MERC

YEP, the only problem is a stock 225 efi on it before pushed the same prop 6200 rpms with no problem with the same gear ratio. I'm goin to pull the fuel rail off next and check for trash. I've never had this much problem out of an efi when everything else is showing ok.????
 

arney

Recruit
Joined
May 21, 2006
Messages
4
Re: 250 EFI MERC

HEY GUYS, Found it!!!! Fuel ecu going full rich @ 4900 rpms!!!! Sent to cdi to test and repair!! DDT doesn't show this problem so don't count on it for all diagnostics!!!!!! Thanks for your input!!!!
 
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