Binding crankshaft on Evinrude 110

joezek

Petty Officer 2nd Class
Joined
May 8, 2011
Messages
137
The crank is binding so bad that the starter wont even turn it over. I pulled the heads, pistons are free to wiggle around. If you turn the crank in reverse it will immediately release and turn free for one turn, then jams and drags severely. Then turn normal direction again and it releases in the other direction again. ALSO once it's released it feels like a one way clutch, the engine will turn one direction but locks when you try to turn backwards.....- until it jams in that direction.


Also, I removed the heads and lower unit trying to figure out whats jamming up.Not sure what is inside the crankcase that could cause that.
 

AEROCOOK

Master Chief Petty Officer
Joined
Jul 28, 2004
Messages
872
So even with the lower unit removed it's still binding? If so, it's likely something internal in the powerhead like a main or con rod bearing. What's the background story on the motor and when / how did this condition present it's self?
 

joezek

Petty Officer 2nd Class
Joined
May 8, 2011
Messages
137
I was in a rush to get some kind- any kind of engine for the next few weekends until I get my 140 up and running again. So this "engine" came up cheap for $300 as a running fresh water pontoon boat trade in from someone upgrading to a 4 stroke. Of course for $300 I couldn't expect much, it had supposedly been sitting in the storage for a year and the shop refused to just throw it away because it was supposedly running when removed.

Basically I stripped and repainted the mid and lower section, sanded and repaired the cover and custom painted everything this week to match my Mako. Also had to swap all my ignition over into this thing because it had a 115 dual powerpack system. I don't know how it could have possibly been running, but after I swapped my ignition it started right up. I only ran it for about 20-30 sec, but it idled perfect, and had excellent throttle response. I did notice from the beginning it was very hard to turn over, and after I ran it it got much worse. After several very short 3-4 second runs the starter quit, I swapped in another and it wouldn't work. With plugs out I still could barely turn it, then pulled the lower unit, still dragging something.

It's so weird that if I turn it backwards it immediately releases whatever was dragging until half a rotation later, then starts dragging in the opposite direction. All the cylinders still look like new, still shiny and cross hatched. There's not a single scratch or line running up and down the cylinders. Also, while it's dragging and very hard to turn over, I can use my fingers and wiggle each piston around in the cylinder, the pistons aren't jamming up in the cylinders at all.
 

joezek

Petty Officer 2nd Class
Joined
May 8, 2011
Messages
137
I just found a picture of the crankshaft for this engine so I can finally picture what I'm dealing with. It looks like the entire crank uses multiple piston style rings in 6 positions. I could imagine one of them seizing and breaking and falling out, then the other half of the ring having a hard time sliding in it's ring land as I rotate the crank. Just a thought. I've worked on and rebuilt car engines for almost 30 years, and airplane engines the last 20 years, never saw the inside of an outboard powerhead before.
 

interalian

Commander
Joined
Jul 23, 2009
Messages
2,105
If one of the crank case sealing rings broke, it wouldn't hang up. Theres nowhere for the parts to hang up.


 
Last edited:

joezek

Petty Officer 2nd Class
Joined
May 8, 2011
Messages
137
great pic thanks, what else could cause it to do this? such a weird problem. Also weird that when it's moving effortlessly one direction, it's like a one way clutch and almost impossible to rotate the opposite direction. maybe a piston ring did break?
 

AEROCOOK

Master Chief Petty Officer
Joined
Jul 28, 2004
Messages
872
Only one way to find out. You've got to take it apart.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,542
Broken piston ring or cracked piston are two things that would cause what you describe.

Time to pull the lower head and split the case and check
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
12,961
Bent/twisted connecting rods, bent crankshaft. Incorrectly assembled or mismatched connecting rod caps. Stuck piston rings, scored cylinders. Con rod bearings piled up. Seized wrist pin in piston.
Don't waste time and money fixing two engines, just get your looper running. As for the $300, really an inexpensive education in 2 stroke 101
 

interalian

Commander
Joined
Jul 23, 2009
Messages
2,105
Bent/twisted connecting rods, bent crankshaft. Incorrectly assembled or mismatched connecting rod caps. Stuck piston rings, scored cylinders. Con rod bearings piled up. Seized wrist pin in piston.
Don't waste time and money fixing two engines, just get your looper running. As for the $300, really an inexpensive education in 2 stroke 101

I'd tear it down just to satisfy my curiosity, even with no intention of repairing. And once apart, the non-ferrous metals fetch a buck or ten.
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,618
Upper bearing failure will drop rollers into upper crankcase causing same symptoms
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
12,961
I too am curious. I just don't want him to pour more money into it. Besides, there's probably a guy near Calgary collecting these engines for Frankenmotors :wink:
 
Last edited:

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,592
Could be a snap ring is gone and allowing the piston wrist pin to move out and catch. Just an idea. :noidea:
 

ricohman

Lieutenant Commander
Joined
Jul 30, 2011
Messages
1,631
I had an RZ500 engine that did the same thing.
The rollers had piled up on one cylinder. I could rotate the motor backwards 1/2 a revolution, but not forward.
 

joezek

Petty Officer 2nd Class
Joined
May 8, 2011
Messages
137
I tore it down just now. The pistons and rings are all in excellent shape.Upper roller bearings aren't really "rolling", more like sliding or dragging on the crank. All that work tearing everything apart and it was just a bearing I could have changed in an hour without even pulling the powerhead, With the bearing off, it spins with just using my fingers, no effort at all.

I have a totally unrelated question now. I noticed that when the pistons are clearing the intake and exhaust ports, they are flush and open to the exhaust ports but the intake ports are almost halfway blocked by the pistons. Why did they even bother having an intake port openings at that specific height when it's useless- they're blocked by the piston. Maybe I have the wrong pistons, or it's designed differently than I would have expected.
 
Last edited by a moderator:

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,297
I believe you need to review the way a 2 stroke motor operates.-----Study this subject ----2 stroke scavenging-----------You do not have the wrong pistons. your understanding of how it works is wrong.
 

Chinewalker

Fleet Admiral
Joined
Aug 19, 2001
Messages
8,902
You want the exhaust ports to open first so the exhaust gasses are exiting before the fresh charge comes in via the intake ports.
 
Top