OIL TANK CONTAINER

[mja68]

Hello,<br />I Just bought a used pontoon boat with a '88 merc 70 h.p.<br />IT has autoblend oil built in.<br /><br /><br />I went to fill the oil tank container,and unscrew the oil cap. I noticed that it had a small "wing nut" in the middle of the filler cap.<br />I unscrewed the small wing nut bolt and unscrewed the main filler cap and topped off the oil.<br /><br />My question is:<br /><br />Is this wing nut bolt should be loose (to vent) or tight.??<br /><br />I left it tight 2 weeks ago.<br />When I went to add oil, I noticed that it was down 2 pints so I thought it was venting fine.<br />However, there seemed to be some air sound coming out when I loosened the wing nut.<br />Now I am worried. !<br />I am worried that the oil tank needed to be vented and I failed to leave it vented for 2 weeks.<br />(even though the engine has run well).<br />The manual only says,"tighten the cap".<br />But, it fails to mention anything about the middle wingnut bolt.<br /><br />Does the oil tank container need to be vented or not???<br /><br />And would the buzzer tell me if it was not getting good oil pressure anyway??<br /><br />Thank you-<br /><br />MJA

 

[wilde1j]

Re: OIL TANK CONTAINER

If it's like most Merc oiling systems, that tank needs to be pressurized (by the engine) for oil to move to the small engine mtd reservoir. I would guess the deal in the middle of the cap is to vent prior to removing for filling. I think it needs to be closed for normal operation.

 

[LubeDude]

Re: OIL TANK CONTAINER

Never seen one like that, but I think it is for bleeding the tank when the engine is running it should be losened untill oil flows out and then tightened. That tank needs to be completly purged of air.

 

[mja68]

Re: OIL TANK CONTAINER

Did I mention that this is a built in oil tank on the side of the engine.?<br /><br />A friend of mine told me that the oil tanks that are on the floor are pressurized.<br />But the "built -in" tanks on the side of the engine need to be vented because they are gravity fed. And should not have the middle wing bolt tightened.<br /><br />??<br /><br />This makes me more confused now.<br /><br />take care,<br /><br />-Mja68<br /><br />ps: It is possible that someone put another cap on.<br />I saw another 70 merc and it had a regular oil cap with a fixed vent in the middle.