Rebuilding a force lower unit--questions

[2FiSh4]

I am going to be replacing the gearcase seals and the impeller on my force 35 hp outboard (1988). The gear case was taking in water due to (I think) a bad prop shaft seal. Question is, can anyone tell me how far the bearing holders need to be pressed into the lower unit housing?? Is it until they are flush with the outside surface??? Is it difficult to get the pin in to hold the shift yoke? Any last minute help I need??? I have the manual so it shouldn't be too bad...I hope

 

[eurolarva]

Re: Rebuilding a force lower unit--questions

The seal has to go into the bearing cage the correct way. I find it is best to pound it in with a long socket. I think the correct size is 3/4 inch socket that works the best. The hardest part is getting the old seal out of the bearing cage. The best tool I found for this is a combination pliers. Once the old seal is out the rest is easy. You tap the new seal in and then tap it back onto the lower unit making sure it goes on straight. When you have the whole lower unit apart it will be pretty obvious how the shift shaft goes. If you have one take digital photos of everything before you take it apart.

Before taking the whole thing apart I would submerge it in water. Replace the vent seal with a rubber plug with a basketball needle in it and blow a couple psi of air in it and see if you can find bubbles. It could be an easy seal that is leaking that dont require gutting the lower unit. Most common place however is the prop shaft seal and unfortunatly there is usually wear on the prop shaft where the seal rides that causes the leaking.

 

[2FiSh4]

Re: Rebuilding a force lower unit--questions

I already have the entire lower unit disassembled because I know there was water in the gearcase and I wanted everything to be cleaned out before reassembly, and I wanted to make sure the gears were OK, and everything is almost like new. Very little wear, etc. I am almost 100% sure the prop shaft seal was the cause of the leak from fishing line getting under the seal and harming it. The prop has splines inside it. When the prop slides off the prop shaft, is that whole unit supposed to stay together? What I am asking is, is the prop shaft seal part of the prop unit or part of the shaft unit? Thanks for the help.

 

[eurolarva]

Re: Rebuilding a force lower unit--questions

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Part number 14 is the bearing cage. Part number 15 is the prop shaft seal which is mounted in the bearing cage. If you bought a seal kit this seal should have come with the kit.