1968 Evinrude 55hp. Low Compression in top cyl. Scorched sleeve

[jbjennings]

Re: 1968 Evinrude 55hp. Low Compression in top cyl. Scorched sleeve

You started up a newly rebuilt engine with dirty carbs???? Why??
Anyway, you can probably make most of the carb gaskets out of felpro gasket material and some leather punches and a pair of scissors and a razor. I'd get new floats, float needles and seats.
Good luck
JBJ

 

[northface]

Re: 1968 Evinrude 55hp. Low Compression in top cyl. Scorched sleeve

"You started up a newly rebuilt engine with dirty carbs???? Why??"

Did I give the impression that I knew what I was doing?? I've never done this before so it's all sort of new to me. So happy we have internet! I'll order the needles and seats and see if my local auto/marine shop has the gasket material.

 

[northface]

Re: 1968 Evinrude 55hp. Low Compression in top cyl. Scorched sleeve

I did take them apart and cleaned them. Inspected the low speed needles as described in the manual. It didn't say anything about mandatory replacements though. Lot of different types of gasket. Which kind should I use?

 

[Joe Reeves]

Re: 1968 Evinrude 55hp. Low Compression in top cyl. Scorched sleeve

Last parts came in on Friday. Compression is good and the motor started right up Had a little trouble getting the low speed settings on the carbs. What a pain. I suspect the carbs will need to be rebuilt to get it running optimal. I can find all of the parts individually but not a rebuild kit. Any ideas on which parts are essential for rebuild?

Fouled carburetors are the reason your engine failed in the first place... carbs clogged = engine runs lean = aluminum pistons flake!

Each carburetor has a brass high speed jet located in the bottom center portion of the float chamber, behind that 7/16" hex head bolt... clean them (3) manually with a piece of single strand steel wire. A restricted jet is a major cause of piston failure.

 

[northface]

Re: 1968 Evinrude 55hp. Low Compression in top cyl. Scorched sleeve

Thanks Joe, I did clean them as the manual instructed. I used a very fine pipe cleaner set. Was able to see through them. I also used a compressor to blow the carbs dry and clean after using carb cleaner. There appears to be no high speed adjustments on these carbs. Only the low speed. I think I found rebuild kits. Will order them and replace the parts.

 

[Joe Reeves]

Re: 1968 Evinrude 55hp. Low Compression in top cyl. Scorched sleeve

Correct... The high speed fuel flow is regulated by the jet and is not adjustable.

The carb kits are mostly gaskets but do include the float needle valve assembly and usually a new float. Adjust them as I mentioned in an earlier reply... and adjust the float as follows.

(Carburetor Float Setting)
(J. Reeves)

With the carburetor body held upside down, the float being viewed from the side, adjust the float so that the free end of the float (the end opposite the hinge pin) is ever so slightly higher (just ever so slightly off level) than the other end. And when viewed from the end, make sure it is not cocked.

NOTE: The forward end of the slow speed adjustable needle valve (3) has a very small nylon bushing to keep it steady. The old one can be a real pain to remove... I have found that the best way to remove it is to insert a small tap into that bushing to drag it out of there. I don't remember the exct size other than it is just big enough to grab the inside of that nylon bushing BUT not big enough to extend thru it where it would grab the aluminum.

To install the new one(s), simply slide it on the end of the needle valve to where it would sit, then install and gently seat the needle valve. The bushing will stay where it belongs when you back the needle valve out.

 

[northface]

Re: 1968 Evinrude 55hp. Low Compression in top cyl. Scorched sleeve

Just wanted to give an update and say thanks, especially to Joe, for all of the help and advise. Had her out yesterday, up over 30mph and running smooth as the day she was built. Spent about $250 and a lot of hrs getting dirty but it paid off. After years of crewing, chartering, and bumming off friends, I finally have my first boat