Model 75 stuck in gear

[seagull101]

Hello everyone,

Got my donor model 75 today!
The only problem is that it is stuck in gear, the bronze 'fork' linkage piece is free and rattles around though!

Any ideas?

Jacob

[Oyster 49]

Strip it down, clean and inspect, to see what's going on.

[seagull101]

Yep, the problem turned out to be that the crown wheel was rusted onto the prop shaft, it freed up easy though.

[Charles uk]

There shouldn't be any water inside that lower unit as it's a sealed unit!
And the crown wheel has a bronze center bush running on a stainless steel prop shaft, so that shouldn't happen.

It might be a good idea to replace both the oil seals with new twin lipped seals, as the original single lipped seals were designed to keep the oil in, not the water out!

[seagull101]

Sorry meant onto the clutch dog and slightly corroded onto the prop shaft!
The gasket that was on it was almost completely gone, i made a new one!

Jacob

[Charles uk]

Gasket paper 10 thou thick, sorry don't understand clutch dog comment as it's pinned onto the prop shaft.

[seagull101]

I just used a weetabix box for that gasket! I did also use sealant though.
The clutch dog is steel and what i meant is that the steel crown wheel and the steel clutch dog rusted together.
You are definitely right that it leaks because after 5 mins running time the new oil looks horrid!
It also looks like somebody has poorly tried to fix the problem as a home made copper pipe collar was round the bottom of the drive shaft.

[Charles uk]

The thrust washer between the end cap & the crown wheel is there to set the clearance between the crown wheel & the pinion, these washers wear increasing the clearance, using a thicker gasket will add to this as well.

Both of these factors will shorten the life expectancy of your lower unit, & all of these parts are quite expensive except the thrust washers, gaskets & oil seals!