Logo
FULL SITE MENU

Evinrude 15hp model 15604A motor issues

Y

yengmaster

New member
Thanks for allowing me in your forum.
First all I AM NOT A MECHANIC. I know just enough to get myself in trouble and be semi dangerous. I have a 1976 Evinrude model 15604A 15hp motor that has not ran in several years but I have recently been trying to get up and running. The coils have have been replaced, spark plugs replaced, fuel pump rebuilt, carb cleaned, and it wants to "lay down" or "bog down" and die if I give it any gas beyond just letting it idle. It seams to idle beautifully but and time I shift it into forward or reverse and give it any throttle it falls flat on it's face. I was told by a "friend" that it needed a "switch box" several years ago when I quit using it, (he said it regulated the spark to the two cylinders???) but have been unable to find ANY information on the so called switch box. So I guess I start there.......Does this engine have a switch box? Is there such a thing? and if so how do I locate one?
 
You need points and condensors for a 1976 15 hp. Buy OEM components and replace all the old with new. That is not a great ignition so it doesn't pay to try and clean just replace them. The gap is .020 for the points and you will need to pull the flywheel to service them. Did you do a proper cleaning of the carb after sitting they should really be soaked and rebuilt with a quality kit.
 
flyingscott,
Thank you for the reply!
I am going to replace the points and condensors as per your advise AND rebuild the carb. I had a friend do it for me and I'm not convinced that he did it correctly.

I've been reading "Leroy's Ramblings" and trying to self diagnose a lot of it. Good stuff but hard to read, A LOT of info in there.
 
Another name for a Capacitor Discharge Ignition "Power Pack". You do not have CDI ignition.

Your high speed jet in the carburetor is dirty. Otherwise called an "orifice plug". It must be absolutely, positivily, squeaky CLEAN. But don't be jamming drills and stuff through it. It is a precision part and too big is just as bad as clogged or dirty.
 
FYI. A "switch box" is a Mercury term for the same basic unit as what OMC calls a "power pack". As was noted earlier, these non repairable, sealed units are the main control unit in many electronic/capacitor discharge ignition systems. Earlier "analog", for lack of a better term, ignition systems, use a type of capacitor to briefly store a charge. This unit called a "condenser". In reality the system that produces spark in the pre CDI motors......still uses capacitor discharge. Condensers are a capacitor, but just considered an older term. So are CDI ignition systems really so brilliant? Ha......I never got stranded out on the lake by a bad set of points, or a "cracked coil". But electronic CDI's have failed me many times, even without so much as a "hickup".
Now, how about that 3.5 MILLION Truck recall?
 
Last edited:
I just wanted to thank you guys for all of your help. I put the carb in an ultrasonic cleaner, rebuilt it with all new parts, replaced the condensers and points and she runs like a top again! I tried to post a video of it running on the water but can't figure out how to post it here. Thanks again!
 
I haven't tried to post a video either so someday when I do I'll just ask my 17 year old son. Good report keep up the great work.
 
Back
Top