Mercruiser 7.4 lit bravo one

[sloopy]

Hi guys!<br />Today while winterizing a 27 foot crownline with a 7.4 mecruiser engine and a bravo one outdrive, we ran into a problem! We can not find any lower unit drain holes on this outdrive, or any way to remove the old gear oil, other than from the reservoir. Does anyone know of the proper way of replacing the lower unit oil?<br />THANKS!

 

[DHPMARINE]

Re: Mercruiser 7.4 lit bravo one

Sloopy first the advice................<br />If you work on these things,get the manual.But with your number of posts,I respect your question.<br /><br />Pull the prop (to lube the splines)and I think you will find the drain plug in the bearing carrier.<br />DHP

 

[sloopy]

Re: Mercruiser 7.4 lit bravo one

ok thanks DHPMARINE! one more question, how do I vent it? through the reservoir? I winterized so many mercs, volvo, omc, Yamaha and many more, this is the first one I have found that has stumped me!

 

[sloopy]

Re: Mercruiser 7.4 lit bravo one

or the first one I will admit that has stumped me

 

[Don S]

Re: Mercruiser 7.4 lit bravo one

My question would be what year???? <br />Those things change now and then.

 

[sloopy]

Re: Mercruiser 7.4 lit bravo one

oh I don't know it is on a fairly large Crownline, the engine has the threads on the oil dipstick tube to help with oil removing with a hand pump, so from that I know it is a younger then a 1995, the boat looks less then 7 years old.

 

[Don S]

Re: Mercruiser 7.4 lit bravo one

What's the last 4 numbers of the hull number? That will give you the year of the boat. That should be closer than a WAG.<br />There was a change in the drives between 95 and 96 and another after 99

 

[Don S]

Re: Mercruiser 7.4 lit bravo one

OK, Just did some checking. On the 95 and earlier, the drain plug was on the forward part of the lower unit (Bullet) on the starboard side.<br />on the 96 thru 98 they were behind the prop. <br />On both drives the vent fitting was on the upper gear unit on the starboard side. Just below the cap.<br />As far as filling goes, you "PUMP" the gear lube in the lower fitting until it comes out the vent fitting. Then put in the vent and keep pumping till it start filling the reservoir. Then put in the fill plug and top off the reservoir.<br />NOTE: Use new gaskets or orings, NEVER reuse them, the will fail and cost you a drive due to water intrusion.