81 Evinrude 25 HP - No fuel to bottom cylinder

[cchildr84]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

Ok folks, I picked the 81 (Original) block up today along with the new pistons. I'm going to start putting the block back together this weekend. Hopefully all goes well. Hopefully by the end of this month I'll have it up and running. I'll post photos as I move along.

 

[cchildr84]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

It shouldnt get hung up on anything. Yep i do it that way, but im not sure if thats the correct way on that motor.
Did you tap it in even with a bit of wood on top or something such like?
I cant remember coming across a seal with a spring on the outer diameter, if thats what it has

I guess I pushed it in to far is what likely happened. I had the machine shop press in the new one I bought, today.

 

[cchildr84]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

Ok. I got the block put back together this weekend. In doing so I've got a couple of questions hopefully you guys can answer for me.

1.) Per the comment from the manual, regarding the bearing shell, did I interperate this correctly? Do I have the shell in the right position. See photo below.



2.) With regards to the sealant at the labyrinth seals, I forgot to place the sealant at these locations. My question is, is it absolutely necessary to do this. I'd like to avoid taking the block apart to place the sealant here if possible, but if it's necessary I will. Please let me know guys.

 

[cchildr84]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

See photos below of the remainder of the re-build thus far.

 

[cchildr84]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

Continued

 

[cchildr84]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

Continued.

 

[cchildr84]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

Continued.

 

[Bosunsmate]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

Looks nice and clean, perfect for a two stroke.
R-egarding your questions
1) Did you line the hole up in the bearing liner with the hole in the crankcase?
2) If the workshop manual says that it needs sealant there then theres most likely a reason for it being there

 

[Bosunsmate]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

Also, are you going to use new conrod screws?

 

[cchildr84]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

Looks nice and clean, perfect for a two stroke.
R-egarding your questions
1) Did you line the hole up in the bearing liner with the hole in the crankcase?
2) If the workshop manual says that it needs sealant there then theres most likely a reason for it being there

1.) Yes. I just wanted to make sure I interpreted the statement of putting the pointed end of the shell towards/on the intake port side.
2.) Dang, I was hoping to avoid taking the block back apart. Can anyone confirm that the sealant is only needed on the crankcase side, as the manual doesn't mention to put it on the block side of the labyrinth seals.

 

[cchildr84]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

Also, are you going to use new conrod screws?

Nope, there didn't appear to be anything wrong with the connecting rod screws. They still look practically brand new.

 

[Bosunsmate]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

Nope, there didn't appear to be anything wrong with the connecting rod screws. They still look practically brand new.

They may look new but the screw threads will be slightly stretched. You will get the correct torque with new ones only. The old ones risk you over torquing or under torquing. They a pretty cheap for what they allow- correct torque on the big end bearings.
Some people add threadlocker to make sure they dont some undone but i wouldnt buy a motor that i knew had that done in it

 

[AlTn]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

the workshop manual instructions <a> state that both halves of the crankcase are to have sealant applied and in order to avoid getting sealant into the labyrinth seal keep the sealant bead 1/4" away from it. You may have gotten enough sealant to seal the halves with a single side treated, hard to say.

 

[cchildr84]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

the workshop manual instructions <a> state that both halves of the crankcase are to have sealant applied and in order to avoid getting sealant into the labyrinth seal keep the sealant bead 1/4" away from it. You may have gotten enough sealant to seal the halves with a single side treated, hard to say.

Ill have to read through the manual again, but I didn't interperate as saying that sealant needed to be place on both the crank case housing and the block. I read it as it just needed it at both the mid & upper section of the crankcase housing, as the step noted in the picture above comes after placing the crank shaft and associated crank bearings and seals in/on the block. As I recall the steps noting the installation of the crankshaft onto the block didn't make any mention of placing sealant prior to, but I'll double check. Have you rebuilt a similar year model motor and placed the gel sealant on both sides? That is to say are those the steps you took during reassembly?

As a general question, what is the purpose of having the sealant at these locations within the motor, once fuel is flowing it all gets lubricated does it not? What is intended to be kept out by placing this gel sealant at these locations?

 

[Bosunsmate]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

As a general question, what is the purpose of having the sealant at these locations within the motor, once fuel is flowing it all gets lubricated does it not? What is intended to be kept out by placing this gel sealant at these locations?

Sealant on the crankcase is to make sure the engine doesnt lean out. Ie it stops any air being drawn from outside the engine and into the crankcase- which is in a vacuum. The intention is to make sure the vacuum sucks through the mix from the carbs and no leakage occurs through the crankcase split gap

 

[Eyeballsdeep]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

Looks to me that the engine had some water damage from either being stored improperly or a gasket issue that went unchecked. Looks like water got to the rings then they rusted up, causing the ring to get stuck then after running full throttle there was blow by past the siezed ring, then eventually heating up the piston enough to melt aluminium. After a pieces of molten aluminium start burning off this is exactly what you get.

 

[cchildr84]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

Looks to me that the engine had some water damage from either being stored improperly or a gasket issue that went unchecked. Looks like water got to the rings then they rusted up, causing the ring to get stuck then after running full throttle there was blow by past the siezed ring, then eventually heating up the piston enough to melt aluminium. After a pieces of molten aluminium start burning off this is exactly what you get.

Yeah, I figured water go it somewhere, just not sure where. It did appear to be prominent in the lower cylinder. During the teardown I didn't see anything, with regards to gaskets, that was a glaring issue. But as part of the rebuild, it's been bored 0.20 over, and is gettingnew pistons, rings, bearings, seals, and every gasket on this thing is being replaced. So hopefully water intrusion will no longer be an issue.

 

[cchildr84]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

Im kind of getting ahead of myself, but I read through the entire powerhead reinstallation section of the manual last night, and no where did it discuss the installation of the flywheel. Is it as simple as sliding it down on the crankshaft and taking and impact drill and tightening the nut, all while using something to keep the flywheel/crankshaft from spinning, and then use a torque wrench to torque it down.

 

[AlTn]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

your question have I rebuilt a similar engine?..yes, 1971 18 hp. 2 cylinder...did I use sealant on both halves?..yes, although more of a "skin" on the the intake side of the crankcase. You are trying to seal the crankcase vacuum and seal the cylinders from each other as well. If you'll go to google imgages and search for gel seal applied to crankcase halves of an evinrude outboard motor I think you'll see what I'm talking about.

Flywheel installation..yes, just line up the slot for the crankshaft key, slide the flywheel on, and torque to spec. I use a strap wrench I made from an old serpentine belt to hold the f/w while torqueing.

 

[cchildr84]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

See item 1 in the picture below. Regarding the gasket that goes between the block and exhaust housing, the guy at the marine shop I bought it from, stated that no sealant was to be placed at these locations. However, reading through the manual, it states to place sealant between the block and gasket, and between the gasket and the exhuast housing. I didn't see anything on the gasket itself stating not to put sealant on it, similar to what is on the cylinder head gasket. The exhaust gasket did appear to have a thin layer of sticky substance, as the plastic package the gasket came in, was stuck to every surface of the gasket on both sides. Any thoughts, should I put sealant or not.

View attachment Blk to Exh Hsg Gskt.pdf