Evinrude 88spl rebuild

[oyster88]

Hello All, I am new to the forum but figured I could find some good information here. I am in the process of rebuilding an 1990 Evinrude 88spl. This is my first two stroke rebuild. I have started to reassemble the engine and I have the pistons and crankshaft back in. Still have standard bore just honed the cylinders and reused old pistons. I have new rings but reused the old bearings. My problem is when I turn the crank over by hand everthing rotates smoothly with no binding or hard spots but there is a poping noise. It is four different pops, and they are consistant with each rotation. I am worried that it may be a bad bearing or a problem with the rings. Or is this normal for a 2 stroke? Possibly just the sound of the rings riding over the intake ports? I am just use to a 4 stroke rotating assembly not making any noise when you turn it over by hand. Does anyone have an knowledge of this? Thanks for the help.

 

[DargelJohn]

Re: Evinrude 88spl rebuild

If you're getting distinct popping noises, then something is wrong. Could be the rings catching in the ports. Did you use standard rings, or oversized?

 

[oyster88]

Re: Evinrude 88spl rebuild

Yes I did order standard rings. One set of rings came in an unmarked box with no part number or any other markings on the box, while the other three sets of rings came in labeled boxes. It could be possible I recieved a set of the wrong size rings. Tonight I will take each piston out one at a time to try to isolate the noise to a cylinder and go from there.

 

[emdsapmgr]

Re: Evinrude 88spl rebuild

It's ok to rering used pistons. The pistons you have should have tiny studs in the ring grooves, on opposite sides of the pistons. These studs are locators that keep the rings centered properly on the pistons. It is designed to keep the ring joint away from the intake/exhaust ports-where their ring ends could catch on the ports-destroying the rings. Surely you rehoned each cylinder prior to putting the piston ringsets back in: I'd look through the exhaust and intake ports of the block. Rotate the crank slowly and visually inspect the new ringsets for any marks of abrasion in that port area. One of the ports may have a high spot which is catching the edge of a ring. Pehaps the honing did not smooth that port area out properly...

 

[oyster88]

Re: Evinrude 88spl rebuild

Im pretty sure it is the rings making the noise while sliding past the intake and exhaust ports. Last night I took the pistons back out and double checked all the ring grooves were clean, checked the ring gap, and made sure all the rings where the same size as the old rings. I used a small file and put a slight chamfer around the edges of the port openings, I think this made a big difference. Also made sure the ring openings match up with the studs in the ring groove. There is still a noticable sound/feeling of the rings catching the ports as they ride over the ports, but not nearly as bad as it was. So now my question is, typically on a two stroke, after you put new rings in and turn the crank over by hand should you be able to hear/feel the rings ride over the ports? If not should I hone the cylinders again to see if this helps? Thanks for the help.

 

[DargelJohn]

Re: Evinrude 88spl rebuild

Should not hear/feel ring passing over ports. Are you using a "bottle brush" hone (pic)? This type of hone will clean up any rough spots around the ports.

Im pretty sure it is the rings making the noise while sliding past the intake and exhaust ports. Last night I took the pistons back out and double checked all the ring grooves were clean, checked the ring gap, and made sure all the rings where the same size as the old rings. I used a small file and put a slight chamfer around the edges of the port openings, I think this made a big difference. Also made sure the ring openings match up with the studs in the ring groove. There is still a noticable sound/feeling of the rings catching the ports as they ride over the ports, but not nearly as bad as it was. So now my question is, typically on a two stroke, after you put new rings in and turn the crank over by hand should you be able to hear/feel the rings ride over the ports? If not should I hone the cylinders again to see if this helps? Thanks for the help.

 

[emdsapmgr]

Re: Evinrude 88spl rebuild

I've never noticed a ring noise when it passes over the ports. Sounds abnormal to me. It's one thing to hear the noise when you rotate by hand. Another when the engine starts up and idles at 900 rpm. Those rings are really hard, but also brittle. Your chamfering of the port edges is a good idea. I've always rebuilt with the factory pistons/ringsets. The factory rings have a wedge shaped taper to the top ring-which makes it slide easier when moving upward. I take it that you have the connecting rod oil hole in the "up" position, with the pistons facing correctly.

 

[oyster88]

Re: Evinrude 88spl rebuild

I figured it out last night. It ended up not having anything to do with the rings. Some how I must have messed up on marking the rods and rod caps when I was taking the motor apart. When I was looking at it last night I relized three of the caps were not exactly matching up with their rod very well. I tried each one on each rod until I found a perfect match. Not sure how I messed up on numbering them, pretty dumb mistake. All back together now and rotates smoothly with no noise.
Education is expensive and time consuming, at least this time it wasn't expensive yet.
Thanks again for the help.

 

[wired247]

Re: Evinrude 88spl rebuild

Ouch. Good thing you caught it now.

 

[DargelJohn]

Re: Evinrude 88spl rebuild

emdsapmgr, Shouldn't the connecting rod oil holes be in the up position? That way they collect oil for needle bearing lubrication.

I've never noticed a ring noise when it passes over the ports. Sounds abnormal to me. It's one thing to hear the noise when you rotate by hand. Another when the engine starts up and idles at 900 rpm. Those rings are really hard, but also brittle. Your chamfering of the port edges is a good idea. I've always rebuilt with the factory pistons/ringsets. The factory rings have a wedge shaped taper to the top ring-which makes it slide easier when moving upward. I take it that you have the connecting rod oil hole in the down position, with the pistons facing correctly.

 

[emdsapmgr]

Re: Evinrude 88spl rebuild

Yes, you are correct, the hole is in the "up" position.

 

[dazk14]

Re: Evinrude 88spl rebuild

Yes, you are correct, the hole is in the "up" position.

I think that would warrant an "Edit" to the previous post.

Some folks actually trust the advice we offer.

 

[emdsapmgr]

Re: Evinrude 88spl rebuild

Done.

 

[dazk14]

Re: Evinrude 88spl rebuild

To the OP...

Are you using the Factory service manual?

It speaks very clearly that rods/caps must be perfectly aligned.

With mismatching caps, it should have never lined up and you would be on this forum asking why.

 

[oyster88]

Re: Evinrude 88spl rebuild

Yes I am using the factory service manual, and yes it speaks very clearly about the alignment. Having numbered them all when taking the engine apart I did not even consider that they could be mismatched. I must have gotten distracted and numbered them wrong. My mistake. Just glad I realized the problem before I got too far.