evinrude 85 crank wont turn but not seized

[wannabewelder]

Why weird???? Even auto connecting rods does this but only occurs when pistons are at TDC

sure at tdc. #3 or 4 is "near the bottom of the stroke and all 4 pistons cant be at TDC at the same time since it wouldn't turn. So if the flywheel rotates and 2 pistons move 1/8" then why would the other 2 in opposing cyl move in the thousandths of an inch? I don't see the play now but it was obvious before I pulled the gearcase. In a car, you'd have bad rod bearings/ crank. I realize this is not a car though but basics are same.

 

[racerone]

I think this is getting more complicated then it needs to be.

 

[wannabewelder]

???----There are some gearcases that supply pressure to a speedometer !!----Not sure why you would think vacuum here.----posting pictures is a good idea too.

I am used to seeing vacuum to draw out moisture. I have never worked on o/b so it seems like a dumb place to put that and a great place to fill your gearcase with H2o. I would have thought low pressure in the gearcase to be the last thing you wold want causing cavitation or something. Did they ever work properly?

 

[wannabewelder]

I think this is getting more complicated then it needs to be.

You are right. This is what happened. I turned flywheel by hand, 4 people watched me, 2 pistons moved 1/8" or so and 2 didn't move 0.040". It sounds completely stupid YES. #3/4 neither at TDC moved. #3 was near bdc so I was scratching my head about a wrist pin issue. Like I said, I have done automotive work professionally and diesels 25 years. If this happened on your car your rod bearing, crank journal or crank is U.S. in the ones with slop, the tight ones normal.
There was a bulletin floating around about the Ford Tritons actually bending rods when head gasket failure occurred and if you don't catch it the SES light comes on and it wont pass emission testing for cylinder imbalance.
I also noted there was no rust and that the pistons moved laterally so the pistons were not seized in the bore.
When I have time, I will fit a straight edge across the top of block, install a rubber spacer and dial indicate the flywheel to the amount of movement before piston pulls away from spacer.
Then I will likely come back here and say 5 mechanics, the oldest 75 ALL need glasses......OR the previous owner did something to it while the plugs were out and he was oiling the heck out of it while he was posting the gearcase for sale.

 

[racerone]

No point in use automotive talk here.----So how many degrees of flywheel rotation do you get ????

 

[wannabewelder]

Why weird???? Even auto connecting rods does this but only occurs when pistons are at TDC

Yes that is correct and it is with the cylinder at TDC and the other on overlap I.E.in an SBC #1&6, 8&5,4&7 or 3&2. In the Johnson the 2 I had the issue with are 3&4. Neither is at TDC or BDC.
It would also be correct IMO to say the same occurs at BDC but NEVER during piston travel.
I should have taken a video of it, I didn't think it would be quite the thing it has become.
It looked like 2 pistons were seized tight and 2 had no needle bearings installed.

 

[wannabewelder]

Why weird???? Even auto connecting rods does this but only occurs when pistons are at TDC

Yes that is correct and it is with the cylinder at TDC and the other on overlap I.E.in an SBC #1&6, 8&5,4&7 or 3&2. In the Johnson the 2 I had the issue with are 3&4. Neither is at TDC or BDC.
It would also be correct IMO to say the same occurs at BDC but NEVER during piston travel.
I should have taken a video of it, I didn't think it would be quite the thing it has become.
It looked like 2 pistons were seized tight and 2 had no needle bearings installed.

 

[wannabewelder]

No point in use automotive talk here.----So how many degrees of flywheel rotation do you get ????

I rocked it over by hand, I would say 10-degrees, I didn't really look that close. What I saw was 2 move and 2 didn't. Automotive or not, it is an internal combustion engine.
What I was expecting to hear from you was to check the rods/ journals. I did check the pistons for drift marks through sp plug holes. Bores were nice, it looks low hours.

 

[racerone]

take it apart---or try jumping up and down in slow motion beside it.

 

[interalian]

Sounds like you need to split the case to figure out what's happening.

But you could start by removing the bypass covers and look at the piston sides. You should be able to see some of them if they're near the top of stroke.

And remove the leg before anything else. A seized lower can look like a locked motor.

And the nipple on the leg connects to a little hole in the front of the leg, a few inches below the anti-ventilation plate. Pressure from the water you're running through exerts through the nipple and to a speedometer. These are notoriously optimistic.

 

[wannabewelder]

Sounds like you need to split the case to figure out what's happening.

But you could start by removing the bypass covers and look at the piston sides. You should be able to see some of them if they're near the top of stroke.

And remove the leg before anything else. A seized lower can look like a locked motor.

And the nipple on the leg connects to a little hole in the front of the leg, a few inches below the anti-ventilation plate. Pressure from the water you're running through exerts through the nipple and to a speedometer. These are notoriously optimistic.

I dropped the gearcase 3 or 4 days ago since I was going to change the impeller. It was seized. The head turns freely now no issue, just questioning why a seized foot would cause 2 pistons to act differently rather than fire the ***** up and cause catastrophic damage like the one I bought for parts with the impeller in the wrong direction (didn't turn clockwise) and needle bearings on top of piston instead of rod journal and painted John Deere green and yellow to boot.

 

[wannabewelder]

I dropped the gearcase 3 or 4 days ago since I was going to change the impeller. It was seized. The head turns freely now no issue, just questioning why a seized foot would cause 2 pistons to act differently rather than fire the ***** up and cause catastrophic damage like the one I bought for parts with the impeller in the wrong direction (didn't turn clockwise) and needle bearings on top of piston instead of rod journal and painted John Deere green and yellow to boot.

I'd agree on the side covers if I even saw a shadow of a score on the cylinder walls. I would maintain the rings and pistons are fine at this stage.

 

[Joe Reeves]

You're overthinking whatever problem you think you have... or had. The lower unit needs reworking or replacing... forget about any L/U problem affecting the powerhead other than jamming it.

The piston moving, some other piston or pistons not moving thing. You can't seem to grasp that the crank doesn't just go down, stop, then start going up.... there's a few thousands whereas the crankshaft either hits top travel or bottom travel and at that point it does not move up or down, it transitions sideways a few thousands to complete its travel to the opposite direction. Forget about it... sorry I mentioned it.

If you're worried about vertical play, wear, whatever.......
********************
(Piston Play Check)
(J. Reeves)

This procedure will tell you if there is any wear or play in the Wrist Pin, Wrist Pin Bearing, or Connecting Rod to Crankshaft area.

Remove the spark plugs. Insert a screwdriver, dowel, punch, or some object of your choice through the s/plug hole and into the cylinder/piston area. Hold the tool lightly against the top of the piston. Turn the flywheel by hand, bringing the piston up to top dead center, then continue turning the flywheel to pull the piston down about a inch..... all the while holding the tool lightly against the piston top.

Now, at the point whereas the piston has been dropped down about a inch, grab the flywheel and hold it firmly. Now, push that tool solidly and firmly against the piston top.

If the piston moves without moving the flywheel, there is a problem (wear, play, clearance, etc) somewhere with the items mention in the first sentence. Be sure to check all of the pistons/cylinders.

********************

 

[wannabewelder]

Joe, I'll let you know what I find. Got other things on the go this week.