Old Lightwin 3hp

[fisheagle]

I have inherited a 1956 Evinrude Lightwin 3hp that was stored since 1982. I have installed new plugs, points, condensors, coils, head gasket and water pump. I have also cleaned and rebuilt carb. This motor idles fine and smoothly accelerates from slow speed to high speed. However, I also own 1996 Nissan 3.5 hp and the Evinrude feels sluggish in comparison. The Evinrude seems to produce approximately 65% the power and speed of the Nissan. I'm not sure if this should be an expected differential or if the Evinrude should produce more power. Compression is 70 psi (too low?) in each cylinder. The cylinders appeared ok when replacing the head gasket. Also, I couldn't synchronize the fuel and ignition because I could't find (worn off?) a mark on the primary pick-up cam to align with the follower. Any recommendations as to performing this synchronization without a visable mark - or is it that important of a procedure in this case?

 

[JB]

Re: Old Lightwin 3hp

That '56 'Rude was rated 3hp at the crankshaft, Fisheagle. It probably made 2.5-2.6hp at the prop when it was new.<br /><br />That is about 70-75% of the Nissan's prop rated 3.5hp, so I would expect about 70-75% of the Nissan's performance.<br /><br />70psi compression does seem low for that engine, but differences in guages and technique, particularly on a pull-start engine, might well show 70psi for a healthy engine. The important measurement is differential among the cylinders. You mention no difference at all. Can't get better than that.<br /><br />Small differences in ignition timing make a lot of difference in small 2 strokes. I would try advancing the ignition timing about 1 or 2 degrees at a time and testing on the water in between. When performance stops improving back it off a couple and leave it there.<br /><br />Good luck.

 

[Mark42]

Re: Old Lightwin 3hp

I think JB meant to write that the '56 'Rude was rated 3hp at the CRANKSHAFT, not the prop. The difference being that the drive line components subtract a measurable amount of HP. So the HP ratings of the two motors are different types of ratings. The Rude being a lower HP motor than the Nissan when compared on an equal basis.

 

[JB]

Re: Old Lightwin 3hp

Mark is correct. I have edited my slip.

 

[Paul Moir]

Re: Old Lightwin 3hp

Not much of a help, but here's a discussion about missing cam pointers on 3hp, click here.

 

[fisheagle]

Re: Old Lightwin 3hp

Thanks guys!