I'm rebuilding my Dad's 25hp Evinrude. I plan to use it on the boat I'm building. It probably hasn't been cranked in 10-15 years, but was running fine as far as I know. I'm ordering a shop manual after this post, but I thought I'd get a head start and at least start to tear it down. I got the flywheel removed. What a pop when it finally breaks free! But I'm missing something when it comes to removing the carb. There physically isn't room to get it to clear the two bolts and the lower part of the cowling.
Do I need to remove the front part of the carb (silencer cover area)?
How do you remove the bottom part of the cowling?
This is my first post on this forum, so I hope my link below works.
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That's a beautiful looking motor, but it doesn't need torn down any more than you have it, except for removing the carb. Change all of the ignition parts if they are original (plugs,points, condensers, coils), rebuild the carb, change the fuel lines to ethanol resistant ones, change the water pump impeller and gearcase lube (don't take out the phillips head screw...) and you're good to go.
Thanks for the help. I got the carb off and it looks pretty good. Just took the float chamber off, cleaned everything, and made sure all the springs, valves operate smoothly. I wish I would have taken a close-up pic of the needle valve before I removed it, so I'd have a good starting point on where to replace it. Hopefully the shop manual I ordered tonight will give the details.
I then removed the power head. I've cleaned one side as you can see in the picture below. Is this normal buildup?
Also, here's a shot of the ignition parts. Does anyone know of a good online retailer that sells a complete tune-up parts package? What should I expect to pay for it?
I have zero experience doing this type of thing, so I might be going overboard like you said. Too late now I guess.
Those coils are newer and will probably still work fine. I'd just clean and gap the points. (but I'm known to be lazy that way!)
The carbon on the pistons can be scraped off gently. As long as there are no scratches or grooves on the sides of the pistons or cylinders, just remove the carbon best you can and you're good to go.
I just picked up a 1970 25hp, but it has internal problems so I will have to split the case unfortunately. Great power/weight ratio on these engines... One of the best ever built!
we all need to support iboats marine store when ever possible. you get, competitive prices. fast shipping, top notch customer service. also it provides us, this great FREE forum.