1979 evinrude 25 HP fuel pump

G

GAJOEY

Cadet
Joined
Nov 28, 2006
Messages
6
I have bought an 1979 evinrude 25 hp model number 25904. the motor was not idling so I started to try and trouble shoot. started out with the carb did not rebuild but it looked real clean.took off the fuel pump and accidently broke off the fuel feed line.After trying to find the fuel pump online I realized the fuel pump on the motor was from a 1982 15 hp motor .My question is could this be part of my idling problem.I am new at outboards.I do not have an manual as of yet but one is on order.Any help would be helpful
 
JUSTINTIME

JUSTINTIME

Captain
Joined
Sep 2, 2006
Messages
3,284
Re: 1979 evinrude 25 HP fuel pump

yes and no

i would suggest a manual and go from there
 
F

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,195
Re: 1979 evinrude 25 HP fuel pump

It could be the idle problem if it is running out of gas at idle because the pump wasn't working efficiently. If that was the cause, it would idle awhile till the carb runs dry, then quit. But that is not the only possible cause. More troubleshooting is in order.

The original part number for your 25hp pump was 385781, changed to 438556. Aftermarket Sierra Marine number is 18-7352. You can get the Sierra one right here at iboats.
 
B

BoaterNut

Recruit
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Nov 30, 2006
Messages
3
Re: 1979 evinrude 25 HP fuel pump

The wrong / undersize fuel pump shouldn't have affected the idle at all. Undersize would cause a starvation at high speeds. You never mentioned if you got any change when you turned the low speed needle / adjuster. If turning it makes no difference at all, then the carb needs a rebuild and the low speed cicuit is clogged / varnish. It's very important that the "tip" of the low speed needle be in good condition, for a good idle adjustment.
 
G

GAJOEY

Cadet
Joined
Nov 28, 2006
Messages
6
Re: 1979 evinrude 25 HP fuel pump

thanks for the help I have now ordered a carb kit,fuel pump.and the manual should be in this week.
 
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