20-25yr old 25hp evinrude

[rpasqually67]

top piston has slight slack. pulled head off found 2 small pieces of metal.rings look good. How do i remove the motor to get inside to check where pistons rides on shaft. I think it might be cracked because pistons still moves in and out. I need to break it down.Model #25502B SER# E0004624

 

[steelespike]

Re: 20-25yr old 25hp evinrude

Your motor is a 1975 I can't be much help about repair except to say don't start any work without a manual.It will save you time agravation and money.
You can find after mareket manuals right here at iboats among many other sources.and possibly the library.
Good luck.

 

[Joe Reeves]

Re: 20-25yr old 25hp evinrude

That's a 1975 25hp Evinrude....32 years old. You'll need to remove anything connected to the engine if there's anything electrical, plus the fuel line, vertical throttle arm, shift linkage, etc.

Inspect the underside of the powerhead and remove the retaining screws, bolts, nuts.

After you have the powerhead off, remove the accessories if you already haven't.... carburetor, flywheel, timer base assy, etc etc, and also the cylinder head and intake manifold.

Now, remove the bolts that secures the forward portion of the crankcase to the rear portion. You can now get at the connecting rods, crankshaft, pistons, etc.

I'd suggest that you make notes and take pictures as you dismantle the engine so as to avoid confusion upon reassemblly.

 

[rpasqually67]

Re: 20-25yr old 25hp evinrude

Thanks im goin in:%

 

[F_R]

Re: 20-25yr old 25hp evinrude

To sum up what Joe said, everything has to come off. Not a job for the faint-hearted or the brave without a manual. When you put it back together, have suitable torque wrenches for the application and use them.

 

[tashasdaddy]

Re: 20-25yr old 25hp evinrude

if you forget to torque one nut or bolt, it could shake itself to death.

 

[itstippy]

Re: 20-25yr old 25hp evinrude

This is one of the oddest posts we've seen in a while.

"top piston has slight slack" - do you mean it acts differently than the lower piston when you turn the flywheel and watch both pistons with the head off?

"pulled head off found 2 small pieces of metal." - in front of the top piston, between the piston and the head? Chunks of metal?

"rings look good" - from where do they look good? Did you pull the exhaust cover and bypass covers and look at the pistons from the side?

It sounds really odd. I'm not sure what you mean about " checking where pistons ride on the shaft", but before you tear the whole thing into pieces it would be nice to try figuring out what you're looking for. I don't see how a wrist pin or rod cap or anything could "get cracked" and send two pieces of metal in front of the piston. Was this thing running and started acting up or what?

If you tear into that motor as you intend to you will need a full gasket set, proper sealer, etc. to put it back together. I cannot imagine doing it without a manual. I'm sure Joe and the others could, but not too many people could. Certainly not me. Put it back together properly without a manual, I mean. I could tear it apart easily enough without one!

 

[F_R]

Re: 20-25yr old 25hp evinrude

Oh, it's not uncommon for bearing cages or whatever to break and send shrapnel up through the intake ports and into the combustion chamber. Results are usually catastrophic.

 

[itstippy]

Re: 20-25yr old 25hp evinrude

Ah. Thank you F_R.

Save the pieces, rpasqually67. You can always get a complete undressed 25HP powerhead and build a decent outboard, or put everything but the stripped powerhead in a basket and sell it on eBay.