Evinrude 6 HP 6303SJ - 01106 Crankcase seals

[w2much]

Curious about these. On the top of the drive shaft is a set of springs and seals held up by a pin. I looked them up and think they were refferred to as crankcase seal assembly. They are missing on my motor. The motor starts and runs fine. <br /><br /><br /><br /><br />What exactly do these parts do? <br /><br /><br /><br /><br />What will happen by running the motor without them.<br /><br /> <br /><br /><br /> As always Thank you in advance for your advice.

 

[Paul Moir]

Re: Evinrude 6 HP 6303SJ - 01106 Crankcase seals

They will make it idle better, and keep the bottom bearing from wearing/rusting out. It also will keep the bottom cylinder from running too lean. Basically, on a 2-stroke, the crankcase and back of the piston forms an air pump that pumps fuel/air mix into the cyliner. Naturally, the crankcase must be sealed for it to work.<br /><br />Since the bottom main bearing is a plain one, it's probably acting as a pretty good seal on it's own. As a matter of fact, a 4hp from that era has no bottom seal at all and relies on the plain bearing naturally. One reason I don't run mine at 50:1.<br /><br />Are you sure the seal is missing? I belive on that model is captured inside a cavity in the mid-section, so you would have to remove the powerhead to find it. I'm not 100% sure though.

 

[w2much]

Re: Evinrude 6 HP 6303SJ - 01106 Crankcase seals

Paul, Thank You for your helpful reply.<br /><br /><br />It is certainly missing. I pulled the LU and noticed the pin thing that holds the parts up at the top of the shaft was missing. I then checked a diagram and saw that there were seals , washers and springs that were supposed to be there. <br /><br /><br /><br />What had me worried was that there was lots of gook in the barrell after having run it. The sludge(gook) continued to come out of the exhaust housing after the motor had been run. I thought it may have been unburned lubricant leaking out the bottom of the crankcase which should have been sealed inplace by the seals . My concern was that should I use the motor it may ruin the bearings thus the power head from lack of lubricant.<br /><br /><br /><br /><br />Again Thanks for your help and advice.

 

[Paul Moir]

Re: Evinrude 6 HP 6303SJ - 01106 Crankcase seals

What I get around here a lot is salt water vapour gets sucked up into the crankcase, destroying the lower crank bearing and sometimes the con-rod bearings. But those are with roller or ball bearing mains.<br />Still, I would get the parts and fix it up. They all show as available, and I don't think they could possibly cost very much (check ishopmarine.com). If I absolutely had to run the engine, it would be on double oil.

 

[w2much]

Re: Evinrude 6 HP 6303SJ - 01106 Crankcase seals

Paul, Thanks a million.<br /><br /><br /><br /><br /> Any thoughts on the sludge?

 

[Paul Moir]

Re: Evinrude 6 HP 6303SJ - 01106 Crankcase seals

Well, a certain amount is normal for any 2-stroke. It doesn't take long to make a barrel a mess even with the small engines. <br />But the engines with bad bottom crank seals sure seemed to produce a lot more of it. I don't know if it was mainly because the bottom cylinder misfired, the top cylinder was running rich (carb adjusted rich to compensate for the lean bottom cylinder), or from the oil that was getting pumped out through the crankshaft seal (unburnt fuel/oil puddles there during idling). Probably a bit of all three.<br /><br />Have a look at the "How much is it worth" thread.

 

[w2much]

Re: Evinrude 6 HP 6303SJ - 01106 Crankcase seals

Paul, Thank You again.<br /><br /><br /><br /><br /> You have put my concerns and curiosities to rest. Perhaps I over thunk it but I am pleasantly surprised that I thunk right.<br /><br /><br /><br /><br /> This forum and its contributers are the best thing that happens to a person once they own a boat / motor.