Lower Seal 305098 Quad Ring issue Evinrude 18HP

[salnaes]

I’m doing a total rebuild of my 1960 Evinrude Fastwin 18 HP mod 15032. For the Crankshaft Lower Seal (item #110 on the image) marineengine provides O-ring #302540 for model 15032, Evinrude 18 HP year 1960. Seloc repair manual Johnson Evinrude 1956-70 talks about a Quadrant Ring as the Lower Seal. I have been searching the Internett to find out what to do. Should I use the O-ring #302540 for this outboard, or should I use the Quadrant ring #305098? I have read that the O-ring #302540 does not seal as well as the Quadrant ring #305098. Right? Well, I bought both, so I may choose. Are there anyone here having experiences with this issue? An advice would be most helpful. Thank you.

[frankr]

Lots of experience.  I prefer the Quad Ring.  The crankshaft moves up and down a bit within the allowable end play.  As it does, the carbon seal needs to remain in contact with the lower bearing ie, it needs to slide on the shaft.  The quad ring is better suited to that sliding action than an o-ring, which tends to roll.  At least that’s what I’ve been taught.  OMC did go to quad rings on their larger engines, I don’t know why they didn’t include the 18-20 which uses the same seal assy.

[salnaes]

Hi frankr. Thank you very much for your reply. It’s very helpful for me now to make a decision. It also agrees with what I have succeeded in obtaining from various sources on the Internet. The only concern I have is wondering why marineengine and other providers still sell the O-ring as part for the Lower Seal for the 18 HP. They could easily have exchanged to the Quad Ring. They sure have both parts in stock.  I’m quoting from the Seloc manual: “Install the quadrant O-seal into the quadrant seal holder with the lip of the seal facing toward the bottom of the cylinder block.”  The quadrant seal holder or Bearing Seal which it’s labeled on marineengine, have both the same part number for the 40 HP and the 18 HP, namely Bearing Seal #302538. So I take it for granted that both the O-ring #302540 and the Quad Ring #305098 fits in the same Bearing Seal #302538. Right? So, very soon I will start assembling my Power Head with new pistons, rings, honed cylinders and new top and bottom seals.

I’m very happy to be here on this forum with so many knowledgeable and experienced users willing to share with less experienced guys like me. Thank you all.

[frankr]

Same carbon seal both engine series.  Same bearing, if I remember correctly.

[Author]

Posts