Unseize 1984 6hp E6RCRV Evinrude.

[cprodave]

Bought this for lower unit parts but top end looks so clean I cannot resist trying to get it to run. Was told by seller it seized up during winter storage. He shot PB Blaster into spark plug holes but didn't remove the head. I removed head, it came off easily. Cooling passages need some cleanout but not terrible. Pistons cylinders had quite a bit of carbon. Soaking with Pistons facing upward now using Liquid Wrench. Had good luck in past unseizing single cylinder lawnmowers by soaking and tapping wooden blocks to single piston. This outboard has both Pistons in mid-cylinder position/stroke. Question is which piston should I tap downward? I am thinking lower piston....any other tips for unseizing? Thanks in advance...

 

[fireman57]

If they have been soaking for a while just turn the flywheel by hand back and forth until they free. Just don't force.

 

[Chinewalker]

If it were mine, I'd pull it down to the crankshaft. ANY rust on the rod bearings or sleeves will cause the motor to ventilate the crankcase in short order. If otherwise clean, I'd pull it down, inspect, and reassemble with known good innards. Also much easier to free up a stuck Piston from the back side, and free up any stuck rings.

 

[oldboat1]

Chinewalker is right, but I've freed up a few using the the method suggested in the original post. Alternate between cylinders using light tapping -- more soaking if no success with that and lightly rocking flywheel as also suggested. If seized up in winter storage as PO said, might be enough to get it up and running. I use a mix of acetone and ATF for soaking.

 

[thatone123]

He may have been giving you the story and it is real stuck from years of rust/salt. Some I have never got unstuck or when I did it was so rotten inside, not worth it.

 

[fireman57]

If it was a larger engine I agree with the tapping but a 6hp he should be able to free up with turning the flywheel. Agreed that some will never free up and they are junk at that point.

 

[oldboat1]

Parts motor maybe. Rarely junk.

 

[fireman57]

Yep, parts engine. Wrong choice of words.

 

[cprodave]

I decided to do a full teardown but got stuck at Step #1--I can't get the Flywheel nut off!

Question:. After soaking with various penetrants, heating with a propane torch (although I couldn't get the nut red hot) is it best to use only a breaker bar on the 3/4 inch socket, or is a hand impact wrench OK? My concern with the impact wrench is that downward force will drive the Flywheel further down on the tapered portion of Crankshaft....not good...

 

[racerone]

You sacrifice the nut !!!-------Cut it off and get a new one if the motor turns out worth saving

 

[kbait]

Air/electric impact wrench should spin flywheel nut off easily. Then 3 leg puller to pop flywheel off tapered shaft.

 

[flyingscott]

As stated above use an air/electric impact wrench to remove the bolt. Then get a flywheel puller that uses the bolts to pull the flywheel. DO NOT USE THE 3 arm gear puller on a flywheel.

 

[cprodave]

Unfortunately I don't have access to an air/electric impact wrench. So it looks like I will be cutting off the nut. I have had good success cutting off stuff with a 4inch Angle Grinder / Cutoff Wheel. But do I need a special small radius wheel to get down into the recessed area of flywheel that "protects" flange on this nut? Should use a drill on the nut/flange in inaccessible recessed area, then split the nut with a cold chisel?

I understand the caution about using puller with 3 bolts on the Flywheel (is this a special tool, or would most autoparts store have one with proper hole location and threads?), although first I will try the "bearhug method"

 

[oldboat1]

looks like trouble brewing. Go to a Goodyear store or similar with the motor in tow, and ask them to spin the nut off with an impact wrench.

 

[racerone]

A bearhug will not take the flywheel off.

 

[kbait]

Puller like this or similar.. use grade 8 bolts/washers

 

[cprodave]

Local tire shop used air impact wrench to remove flywheel nut, no problem. I got a puller shaped like Kbait photo. Looking for Grade 8 bolts/washers now. What thread do I need? Seems like 12NC24 is closest (but not perfect) fit, M6 not so good. Also I am aware to leave nut loosely on crankshaft to control the possible "explosion" when flywheel releases. Thanks all...

 

[racerone]

It has been 1/4-20 NC on the smaller motors since about 1950.------And no you do not always need grade 8-----I use grade 5 bolts and no problems.

 

[tomhath]

I've always been able to get the nut off by removing a spark plug and stuffing a length of rope into the cylinder. Then use a wrench, the piston can't get to the top so you can loosen the nut.

When you're using that puller, whack the top of the screw with a hammer occasionally, it helps break the taper lock.

 

[cprodave]

RacerOne, I'll be darned, it IS a 1/4-20. Thanks, I will buy appropriate bolts tomorrow and post an update.

TomHath, I use the rope trick quite often on mowers, chainsaws, outboards, etc. In this case it wasn't necessary due to Pistons being seized. I will use your tip tapping the puller center bolt occasionally.

Thanks again folks.