70 Hp. Evinrude

[oldcatamount]

This is a picture of a piece of broken ring that has pierced the crankcase on a '83 Evinrude 70 hp. Is this something that can be welded?

 

[Faztbullet]

Re: 70 Hp. Evinrude

The crankcase half can be weld but yuou need to tear motor down first as doubt ring debris did this....

 

[oldcatamount]

Re: 70 Hp. Evinrude

Thanks Fatz, I found pieces of broken rings behind the reeds on cylinder #2, then I saw the crack and the piece sticking through. Thought I should ask about the welding before I tore it down completely. Something is still jammed in there because I can't turn the flywheel more than 1/2 turn in either direction. The piece sticking through is about the same size as a piece of ring but, I'll find out soon.

 

[boobie]

Re: 70 Hp. Evinrude

Tear it completely down and you'll know the whole story.

 

[boobie]

Re: 70 Hp. Evinrude

Post some pics when it's all down. Interesting ??

 

[Boater420]

Re: 70 Hp. Evinrude

If you need any parts for that thing you cant find I have three 70s in my garage now.

 

[oldcatamount]

Re: 70 Hp. Evinrude

Good to know Boater

 

[Joe Reeves]

Re: 70 Hp. Evinrude

This is a picture of a piece of broken ring that has pierced the crankcase on a '83 Evinrude 70 hp. Is this something that can be welded?

Never seen a broken ring travel in that direction... normally travels to the top of the piston, cylinder head, exhaust port. More likely a connecting rod needle bearing, especially since the flywheel can't be rotaed 360 degrees. Let us know what you find.

That area has no great amount of pressure generated within it... you can either have it heli-arced, OR use "Gray" Marine-Tex which is an epoxy solution (it will hold - trust me). If using Marine-Tex (the gray epoxy...not the white stuff!), sand the area down to bare aluminum and clean it with either lacquer thinner of acetone first.

The "gray" Marine-Tex epoxy.... just for experimental work, I patched two 225 looper engines that had baseball size holes in that intake area. Used masking tape as a backup support, then applied layers of Marine-Tex, letting it dry overnight, then removed the masking tape and shaped the epoxy as needed. This was back in the early 1990's... the engines are still running.

When they fail, if ever, I'll let you know so that you don't waste your time.

 

[SigSaurP229]

Re: 70 Hp. Evinrude

Joe thats amazing.

 

[oldcatamount]

Re: 70 Hp. Evinrude

Thanks for the tip on Epoxy and you guys are right, the piece that pierced the casting is a piece of the bearing cage for the middle cylinder. I have no idea what caused that but, there are no broken rings at all. I'm going to send it to the machinist and then make my decision as to continue or not. Any thoughts or suggestions?

 

[Joe Reeves]

Re: 70 Hp. Evinrude

In all probability, that cylinder was run with a fouled carburetor which resulting the the cylinder running lean (poor or no lubrication). Check that cylinder's piston skirt and cylinder wall also.

Note: The crankshaft cannot be undercut (downsized).

 

[oldcatamount]

Re: 70 Hp. Evinrude

The piston skirt has a chip missing and the exhaust ports have some "galling"(?). There is a single score mark inside the cylinder and some slight scuffing on the piston skirt. The crankshaft journal for that cylinder has a "texture" and also looks a bit blue like it was over heated. I wonder if I can still use that crank?

 

[boobie]

Re: 70 Hp. Evinrude

See what the machine shop has to say. Or try cleaning it up with some crocuss cloth, mike it up and see what happens.

 

[phillnjack2]

Re: 70 Hp. Evinrude

well the crank can have new metal put on by welding then just machining down to size.
the piston chip is nothing to worry about and can by the looks of it be cleaned up with a bit of emery cloth or wet n dry.
the actual bore just might be ok with a hone.
while down i would hone the bores for sure and put in new rings anyway, this will save time in the future for sure.
get the case welded being as it is stripped this far.
new main bearings all round and new main bearings n seals, new big ends, new small ends and you have a recon powerhead.
i take it the cylinderhead is not damaged in any way at all ?
and while its down clean up in the exhaust port area and inlet area before getting it honed out.

looks like you were lucky, another few minutes and the whole thing might have been scrap.


what were the symptoms when this happened to the engine ?

phill

 

[Faztbullet]

Re: 70 Hp. Evinrude

From the pic's you posted you got the good "A"beam rods and mike them cylinders as the one that failed is worn bad. Anytime you see the "beer bottle brown" in a cylinder that a sign of a worn and glazed cylinder. If cylinders is .003 out of spec bore it....

 

[oldcatamount]

Re: 70 Hp. Evinrude

No info from previous owner as it came as part of a trade in but I believe Joe when he points to the middle carb being clogged. I'm going to send the block and crank to a machinist that I trust and get an estimate first. All other parts on the motor appear ok and original so I'm willing to do the rebuild.

 

[F_R]

Re: 70 Hp. Evinrude

A previous post casually mentioned the exhaust ports area. I'd modify that to say be sure to inspect that area very closely. Those motors have a problem with the exhaust cover baffle plate warping. That lets the gasket leak. Water from that leak can and does squirt into the exhaust ports and do major damage.......for instance failed bearings!!!!! Especially the middle cylinder which seems to warp the most.

 

[oldcatamount]

Re: 70 Hp. Evinrude

F-R, this is my baffle plate and it looks (to me) like it was leaking like you said. What do you think?

 

[F_R]

Re: 70 Hp. Evinrude

My guess is that it was, but not as bad as most I've seen. Perhaps somebody with a milling machine could true it up?