25 Evinrude won't run @ WOT

[Harry B.]

I just acquired a 25 hp. 1974 Evinrude. She'll run great at idle and up to about mid range but soon as you pour the coals to her she bogs out and dies. If you pull the choke open the RPM comes up pretty good but not 100%. If you fiddle with the carb linkage with the throttle wide open it will come up and run at top RPM just fine.
What the heck is going on. Do I have a plugged up carb??
Is carb linkage screwed up? Any suggestions??? Thanks much in advance!!!

 

[1730V]

Re: 25 Evinrude won't run @ WOT

Define "fiddle with the carb linkage".

 

[tashasdaddy]

Re: 25 Evinrude won't run @ WOT

clogging high speed jet, time for a cleaning and carb kit. and you need to do a link n sinc.

 

[Harry B.]

Re: 25 Evinrude won't run @ WOT

Define "fiddle with the carb linkage".

If I monkey with the throttle plate (I guess its also called the butterfly valve too?) and/or have the choke on it will run great.

It will run just so-so (lower RPM) with the choke on. If I adjust the air intake/mess around with the carb plate and close it off even more, the rpm comes up and it will run wide open very well.

Plugged high speed jet and orifices? Poor fuel pump?
Can it be linkage as there is no linkage that closes or is supposed to close the throttle plate/butterfly when you throttle up is there?

 

[tashasdaddy]

Re: 25 Evinrude won't run @ WOT

what you are saying with your fooling around is you close off part of the air, with the plate and add gas with the choke to make it run wide open. thus it is starving for fuel. equals clogged high speed jets in the carb, they are not delivering enough fuel to air. completely clean, remove the jets, and use a carb rebuild kit. the link and sinc, is a set by step process that sets the electrical timing and the carbs together, so they work together.

 

[Harry B.]

Re: 25 Evinrude won't run @ WOT

Thanks much!!! I'm not all that great of back yard mechanic as you can tell by the lack of knowledge of carbs since everything is fuel injected now. I'm fairly mechanically inclinded, but not that experianced, but I don't want to pay $100/per hour for a mechanic if I can help it. Most shops don't want to work on anything older than 1997, and state with older motors "if its not one thing then its another, and we rarely have happy customers because another problems arises making them believe we didn't address thier original problem." Besides, I acquired the motor for $100.

How big of a deal is it to tear down a carb, clean it and put in a new kit and then adjust everything back to sync? I've got a manual but it is far from detailed. I believe its a Seloc manual and it, in my opinion is a P.O.S.

 

[tashasdaddy]

Re: 25 Evinrude won't run @ WOT

go here follow the prompts, look up the motor and the carb diagram..it is one of the simplest carbs to do. you need a special tool to do the high speed jet. i made one from a screwdriver tool # 317002.

 

[tashasdaddy]

Re: 25 Evinrude won't run @ WOT

you can see the tool in this thread, new computer, everything not loaded yet. http://forums.iboats.com/showthread.php?t=216968&highlight=carb+tool

 

[Harry B.]

Re: 25 Evinrude won't run @ WOT

Your a man amoung men tashasdaddy. Thanks much for all of your help. This weekend I'll tear into it. Got to get it up and running for the rest of the goose hunt!! Thanks again!!!