A friend just bought a used Lund with a Merc 115 2 stroke. When the motor is trimmed up, it leaks 2 stroke oil all over the splash well. Can anyone explain how this cap is supposed to work?
7BC1C348-AD46-4A77-95A9-AF34828172CC.jpeg
D1281280-0953-4C25-B85E-66995CCE51BA.jpeg
Looks like the cap may have been overtightened and cracked https://www.in-depthoutdoors.com/community/forums/topic/alumaboats_1238009/
Is the screw what tightens the O-ring?
turn the yellow cap and it will squeeze the o-ring for a seal.
is that a crack in the cap?
is that a crack in the cap?
A piece of dog hair. Lol!
Okay, I tightened the yellow cap as tight as I dare with a pair of channel locks and it still wobbles in the throat of the tank.
Okay, I tightened the yellow cap as tight as I dare with a pair of channel locks and it still wobbles in the throat of the tank.
The yellow cap will always be “loose”. The yellow portion of the cap is basically just a hand wrench for tightening the seal (o-ring). The sealing is done by the metal disks and the o-ring. Finger tight is all it should need to be. Any tighter and one runs the risk of something breaking and ending up worse than when one started.
I’d check the tank opening for scratches or out of round condition causing the oil to leak past the o-ring. Check the o-ring itself for cuts or nicks. Might want to peel it completely off, so you can check both the ID and the OD.
There might possibly be a small o-ring around the bolt, which might be the source of the leak. I don’t recall just how this is built. If you can furnish a model and serial number, then it can be looked up and confirmed by the parts list drawing.
My guess is it got tightened too much and stretched out the throat of the tank. Not sure what can be done about that now.
Maybe put a good quality hose clamp around the outside of the tank throat and tighten it with a nut driver (not a screwdriver unless you want it lodged in your hand). There’s a chance you can squeeze down the diameter so that the cap makes proper contact.
If you can furnish a model and serial number, then it can be looked up and confirmed by the parts list drawing.
The motor is a 2000 Merc 115, ELPOT
biggil, I’m feeling your idea that the throat might be stretched as the whole cap moves when tightened to the nuts. The hose clamp idea would also be an easy farmer fix to try without buying any parts.
Huntindave wrote:
If you can furnish a model and serial number, then it can be looked up and confirmed by the parts list drawing.The motor is a 2000 Merc 115, ELPOT
DFI, EFI, or carb ? 4 cylinder or 6 cylinder?
Serial number needed to pull up the correct drawing.
And yes, it is plausible the tank opening has stretched over time. Not sure if it can be compressed much if at all.
It does not appear that there are any individual components listed for the cap assembly except the cap itself, the large o-ring, the dipstick and the nut holding the dipstick.
If one needs to replace anything your choices seem to be
(A) a new cap assembly
(B) a new tank assembly
I’m not just sure what Merc considers an “assembly” in regards to these parts. Probably best to discuss this with a dealer before ordering.
Or just ditch the oil injection and add the oil to the gas in the tank
Or just ditch the oil injection and add the oil to the gas in the tank
This would work. How about putting a double layer of plastic wrap over the tank opening and then installing the cap? The plastic wrap will have to be replaced whenever refilling the oil tank but that isnt going to be all that often. Another question, is that tank just a reserve tank or the only oil tank? Is there a remote tank mounted in the bilge?
Exact same motor (I think). Is there a bleeder hole past the yellow cap towards the back of the motor? If I over fill my oil to a certain point and trim my motor up, oil will leak out the bleeder hole. I had to mark a line on my resivior as not to over fill.
Are you sure it is oil and not mixed oil/gas? The carbs will leak on those when trimmed up too far, no way around the carbs leaking that I know of.
When the motor is trimmed up the faucet drip is visible from the cap lip. The hose clamp has in fact seemed to have stopped the leak.
My 99 75HP merc does the same thing when I over fill it. I topped it off emptying a gallon out last fall before storage. Figured it would be better to put it in the tank and not risk the jug falling over an leaking all over. I was wrong. What a mess.
When the motor is trimmed up the faucet drip is visible from the cap lip. The hose clamp has in fact seemed to have stopped the leak.
Nice 
I had a 98 75hp that the cap leaked on too.
My solution was just to never fill the tank completely.
When the motor is trimmed up the faucet drip is visible from the cap lip. The hose clamp has in fact seemed to have stopped the leak.
Check is in the mail I assume? I accept bacon and smoked pork butt as payment.
<div class=”d4p-bbt-quote-title”>SuperDave1959 wrote:</div>
When the motor is trimmed up the faucet drip is visible from the cap lip. The hose clamp has in fact seemed to have stopped the leak.
Check is in the mail I assume? I accept bacon and smoked pork butt as payment.
You bet. lol. I had the right size clamp on hand, I love free boat repair.
You must be logged in to reply to this topic.
