1971 60hp Evinrude rebuild -Please help!

[Carolinariggin]

Hi guys,<br /> I'll be honest, I don't know as much about outboards as I do about cars but I'm well aware of the basic and internal operations of the motors. I'm 18, very intelligent, and a current engineering student in college. My problem has occured with my 60hp Evinrude. I lost compression in the middle cylinder and scarred it pretty bad. Not having the outrageous money the local shop wanted to rebuild it, I decided to tackle the old motor myself. I had the middle cylinder bored .030 and replaced the piston and rings on my own. I also replaced the rod bearings for this cylinder since I suspected the carb was clogged and they might have been damaged too. (the gas is the oil too, and it goes right around this bearing....) I reassembled the motor (yes, I torqued all the bolts to spec and matched the bearing caps) and hauled it to the shop to finalize some wiring i carelessly forgot to mark. The shop told me I had assembled the motor with an incorrect gasket sealant and that there was a bind in the motor, noting that it was probably from a mistake in rod bearing assembly. I used a high temp RTV that we use on the race track. It holds up on motors in excess of 500 horsepower and is subjected to temperatures in excess of 600 degrees. Will it not work at all? I'm sure I assembled the rod bearings right and the flywheel turns smoothly by hand, so the "bind" is very questionable to me. Do they sound like they are trying to take advantage of a young kid? Supposed I completely tear down the motor again to change gaskets and sealants. Can anyone offer any tips on assembly or break-in to help me do it right? <br /> You're thinking dumb kid by now, i know, but this is the way I look at it: If I bomb on this deal I bomb out, but if i do it right, i've got 250 bucks in a rebuild!! I've never been afraid to tackle a project and this has been a risk I decided to take. You'll never learn if you don't try! Please help me get this thing on the water!!<br /><br />P.S. I haven't turned this thing over with the starter because I don't want to damage anything internal if by chance i messed up, and I will rebuild the carbs if I turn it over and the compression checks out. Something had to cause it to mess up in the first place!! <br /><br />Thanks Everyone,<br />Aaron

 

[Joe Reeves]

Re: 1971 60hp Evinrude rebuild -Please help!

Aaron..... I don't approve of using any sealer except as recommended by OMC (RTV is not on their list). However, if it works for you, that's what counts. <br /><br />This binding?? Remove the spark plugs and turn the flywheel by hand, turn the engine over a few times. If there's any binding, you'll surely feel it while doing that.<br /><br />If the above is okay, check the compression. You should have 100+ psi and even on all cylinders. Now, check the spark with the s/plugs removed. That spark, on that model, should jump a 1/4" gap with a strong blue flame on all cylinders. If not find out why.<br /><br />The usual cause of a powerhead failure (they don't fail by themselves, something caused it) is either faulty ignition which would result in what a mechanic would call a "Wash Out". This is where the fuel wouldn't get burned properly, the cyl loads up with fuel, the gas eventually overcomes the oil mixture, and the lubrication factor goes to pot, resulting in the piston being torn up.<br /><br />The other cause, and the most common cause, is fouled carburetors. The carburetor(s) become gummed, fouled, clogged, and cause the engine to run lean. This results in poor lubrication, excessive heat, pre-ignition etc. Bottom line is that it is a absolute must to rebuild the carburetors when doing a powerhead rebuild.<br /><br />Let us know how you make out.

 

[Carolinariggin]

Re: 1971 60hp Evinrude rebuild -Please help!

Thanks Joe,<br /> Gonna get to work on it pretty soon, I'll let you know.<br /><br />Aaron