pressure in lower unit on 1987 50hp johnson?

[fpctim]

i pulled the drain plug to change lower unit oil and it was under a lot of pressure is this normal?if not what could be wrong?

 

[OBJ]

Re: pressure in lower unit on 1987 50hp johnson?

fpctim...what did the oil look like and were there any metal shavings in the oil?<br /><br />OBJim

 

[fpctim]

Re: pressure in lower unit on 1987 50hp johnson?

no metal shavings and the oil was black and it smelled bad

 

[fpctim]

Re: pressure in lower unit on 1987 50hp johnson?

there is also no water in it, i went out and lost my gears ,when i pulled the plug to look at the oil thats what i found ,i pulled the lower unit and i can engage the gears now ,before i could not get any gears while it was under pressure

 

[fpctim]

Re: pressure in lower unit on 1987 50hp johnson?

help

 

[alcan]

Re: pressure in lower unit on 1987 50hp johnson?

Don't know what to tell you. Everything sounds normal, right down to the smell. My guess is maybe someone used the wrong oil trying to save a buck, or by mistake. This shouldn't affect shifting though. Maybe one of the other guys can shed some light on this. You can't beat that smell!

 

[ob]

Re: pressure in lower unit on 1987 50hp johnson?

fpctim,I don't know what you are considering as high pressure but it is unlikely in had more than around 10 psi in it when plug was removed.If anything ,to me , that is an indication of<br />1-Lower unit is more than likely not leaking<br />2-probably just built up form temp/pressure change.<br />3-I don't think it would have anything to do with a shift or gearing problems that you mention in this post.<br /><br />Can't advise any further on what problems you may be experiencing with shifting or gears without more input.The dark color of the lower unit oil is normal for one that hasen't been serviced for some time.The smell of gear oil is also not one of my favorites and no cause for alarm.

 

[fpctim]

Re: pressure in lower unit on 1987 50hp johnson?

i had the the power head rebuilt on this motor and asked the shop to change the oil and they did like a month ago and i have only been on the water once.

 

[ob]

Re: pressure in lower unit on 1987 50hp johnson?

If the oil was that dark after only using once after an oil change I'm guessing the oil didn't get changed.

 

[fpctim]

Re: pressure in lower unit on 1987 50hp johnson?

he had to of changed it because he put new drain plug in, i had a flat head screw in it when he got it and it came back with a phillips screw

 

[ob]

Re: pressure in lower unit on 1987 50hp johnson?

Something is amiss in either the lower unit or the type oil used.If you didn't find any trace of metal or water intrussion when draining,lower unit oil simply doesn't turn black that quick.Problem with exhaust porting through hub?Change again,run test,and inspect.If same you need to drop LU and have a looksy.

 

[fpctim]

Re: pressure in lower unit on 1987 50hp johnson?

i put new oil in and i put the lower unit back on the boat ,i fired it up and got first and second ,i let it run in gear for a half hour ,then it did the same thing no gears again ,drained the oil and it looked better but still black and im an auto tech and ive smelled my share of gear oil in my life but not like this,anyway refilled the lower unit with new oil again and ran it for about 45mins more and it happened again no gears ,im stumped

 

[rickdb1boat]

Re: pressure in lower unit on 1987 50hp johnson?

Tim,<br />Put the lower unit back on being careful to pay particular attention to the linkage. Look for anything that may have been incorrectly installed or come loose. Fill it up with fresh fluid and give it a go. Make sure after you get it back on that the shift shaft is working properly(By Hand). The pressure and oil sounds right, although if they just changed it and it's real black, I would be suspect of their work. I can change those screws and hardly lose a drop!! Could have been some foaming of the oil that caused the pressure?? Not sure, but like OB said, at least you know it's not leaking!

 

[ob]

Re: pressure in lower unit on 1987 50hp johnson?

Drop it and checkout your exhaust boots is all I can think of.

 

[fpctim]

Re: pressure in lower unit on 1987 50hp johnson?

thanks, ob and you are right im very thankfull its not leaking

 

[fpctim]

Re: pressure in lower unit on 1987 50hp johnson?

one thing how can you change the screws with out it shooting out it was a week later and it had lots of pressure still

 

[ob]

Re: pressure in lower unit on 1987 50hp johnson?

It shouldn't be building pressure over and over again.You've got a problem somewhere.Only pressure source after running would come from exhaust leak through shift rod seal or fracture.

 

[rickdb1boat]

Re: pressure in lower unit on 1987 50hp johnson?

Seems like after it sat for a week, it would leak back out again and relieve the pressure. Unless it's taking some exhaust pressure to force it in there and the seal is not allowing all of it to escape. Got me!!??

 

[fpctim]

Re: pressure in lower unit on 1987 50hp johnson?

got ya i will get on it

 

[alcan]

Re: pressure in lower unit on 1987 50hp johnson?

Drain oil and perform vacuume test.