Reply To: MERCURY MARK 55 LOWER CRANKSHAFT SEAL

[jrm80]

THANK YOU FOR THE REPLIES. LABRADOR IS CORRECT IN THAT THERE IS ONLY ONE SEAL IN THIS ENGINE AND NO ROOM FOR A SECOND SEAL. THE NEWER MERCURY 500 WHICH FOLLOWED THE MARK ENGINES SHOWS TWO SEALS, BUT THAT IS NOT WHAT I’M DEALING WITH. MY PRIMARY REASON FOR ASKING THE QUESTION THAT I DON’T UNDERSTAND HOW A TWO CYCLE ENGINE THAT RELIES ON CRANKCASE PRESSURE TO RUN CAN HAVE A BUILT IN LEAK LIKE THIS AND BE EXPECTED TO RUN PROPERLY. IT RATTLES MY ENTIRE CONCEPT OF HOW A TWO CYCLE ENGINE IS SUPPOSED TO RUN. BE THAT AS IT MAY, THE MERCURY ENGINEERS DECIDED THIS SEAL SHOULD HAVE A HOLE IN IT AND I’M JUST TRYING TO FIGURE OUT WHY.

THEN THERE’S THE THE COST QUESTION. THE UPPER SEAL I CAN GET FOR ABOUT 7.00, BUT THE LOWER SEAL ALTHOUGH NLA ARE AVAILABLE FOR ABOUT 30.00 OR MORE. FOR THE DIFFERENCE, I THINK I CAN MANAGE TO DRILL A 1/16 HOLE INTO AN UPPER SEAL AND MAKE IT INTO A LOWER SEAL. ALTERNATIVELY, I COULD JUST PUT AN UPPER SEAL IN THE LOWER END CAP AS LABRADOR DID AND BE DONE WITH IT.

ANYHOW, THANK YOU FOR THE REPLIES. MAYBE I’LL JUST FLIP A COIN AND LET A DIME DO MY THINKING.