lower unit help

[KRISTIAN1979]

1996 75hp 2 stroke 0g421706

I shifted control box into forward before pulling the lower unit to replace exhaust tuner and water tube lower unit has been in forward gear and off motor for almost 3 weeks while waiting on parts and getting the exhaust plate from machine shop. finished putting everything back together yesterday let it sit for 24 hours for all gaskets and RTV to set started it today and all other problems are fixed but now the lower unit is stuck in forward gear . pulled LU back off put in vise and worked shifter by hand at lower unit and moves freely but won't come out of forward gear .

please help boat has been down for almost 2 months


thanks in advance
kristian

Seloc manual has been no help

 

[Bamaman1]

Re: lower unit help

Have you by chance drained the lower unit lube into a clean drain pan?

Is there any water intrusion in the lube? If you're having problems, you may have had bad seals and water causing gear and bearing problems.

You might want to run the lower unit to a qualified independent marine mechanic to have checked out. Seals are often a $300 repair including labor. And if they must disassemble the lower unit for inspection, you want someone that knows lower units to do the job. Lower units have a bunch of little parts.

 

[Texasmark]

Re: lower unit help

Have you by chance drained the lower unit lube into a clean drain pan?

Is there any water intrusion in the lube? If you're having problems, you may have had bad seals and water causing gear and bearing problems.

You might want to run the lower unit to a qualified independent marine mechanic to have checked out. Seals are often a $300 repair including labor. And if they must disassemble the lower unit for inspection, you want someone that knows lower units to do the job. Lower units have a bunch of little parts.

+1.

The shift lever is splined to a cam with the FNR detents. Each is a different distance from the cam pivot point.

The drive shaft keeps the F and R gears rotating as long as it is.

The shift function is per a thing called a clutch dog which is a sliding gear pinned (locked) to the prop shaft and operated back and forth by spring pressure from the cam follower and spring (and 3 ball bearings to set the load) located in the front end of the prop shaft which follows the detents in the cam. It locks to the R gear in reverse and in F gear it locks in the drive direction but ratchets in the reverse direction....called an overrun clutch used when the prop is turning faster than the engine.... when decelerating. Obviously in N it rides in the middle and touches neither gear.

Since the system depends on spring pressure to push the dog back to N and R, having water in the LU could rust things up and keep it from moving from where it was, or the spring could have broken.

If you used Quicksilver premium oil in your LU it's blue black in color. Any discoloration of the oil, like yellow or chocolate or actual water droplets means trouble.

HTH,
Mark

 

[carholme]

Re: lower unit help

Your s/n comes up as:

MERCURY - ( 75 H.P. (1996 ))
Serial No: 0G421706 Model No: 1075412SD

Parts and Service Bulletin List for s/n 0G421706:

Search Results - Crowley Marine

See CLUTCH FAILURES - 75 THRU 125 in the SB list to make sure you are affected or not.

Mercury service manual is 90-830234R2 and if you send me a PM with an email address, I will send you a copy.

Gerry

 

[KRISTIAN1979]

Re: lower unit help

Thank for the replies
Had leaking seal below water pump plate before replaced that plate an seal and changed oil in Lu and worked after all was done out on water then the water tube upper seat was bad had to pull the mid section completely apart to fix and in the 3weeks of waiting on parts and machine shop time put all Back together and Lu installed

Lu oil looked brand new and the splined shaft shift rod on back of Lu moves freely with no resistance and no noticeable notched feel thru full movement.

Carholme pm sent