1988 Force 125 Lower unit question

[roscottjr]

I am resealing the lower unit on my 1988 Force 125 but have run into a slight situation. In the manual it specificaly states with a warning that the gear housing cover is bonded with rtv sealant, however, it says nothing about using rtv sealant when reassembling. I know this has O-rings already but should I use the rtv sealant to bond it to the case as it was before?

Also, my gearcase seal kit I got for this motor has all round O-rings. I have doublechecked to be sure I have the correct set and I do. However, 1 of the O-rings for the gearcase cover is oblong shaped and not round. Do they not make the oblong shaped ring and this round ring works fine?

Robert

 

[john from md]

Re: 1988 Force 125 Lower unit question

1. I would use RTV, just don't overdue it so that it gets into the gearcase or on moving parts.

2. When orings are compressed for years, they sometimes take a set and can look square.

John

 

[roscottjr]

Re: 1988 Force 125 Lower unit question

I am a little partial to the black rtv sealant. Is there any reason to not use this type on the gearcase?

Robert

 

[john from md]

Re: 1988 Force 125 Lower unit question

RTV makes a Marine sealant and I would use that.

John

 

[roscottjr]

Re: 1988 Force 125 Lower unit question

What is the purpose of the extra seal that comes in the gearcase seal kit? It looks like a driveshaft or propshaft seal but is not the correct size for either. There were a total of 3 seals of this type in the kit, 1 being for the driveshaft, 1 for the propshaft, and then this extra seal. Is this seal just simply an extra unused seal in my case? I am thinking maybe this set covers several different gearcases and thats the reason for this seal. The manual, diagrams, and everything I can find on the 125 do not show this seal at all.

I did not install this seal as there was no place for it. However, I did complete the resealing of the gearcase and it is on a pressure test right now of 13psi. It has been under pressure for 30 minutes now, I am planning on leaving it another 15 minutes and will then be putting it under a 10psi vacuum test. The prop shaft seal leaked at first but it has been taken care of and now does not leak. Will update later on the test.

Robert

 

[john from md]

Re: 1988 Force 125 Lower unit question

I have bought seal kits that had seals that I could not identify. I think you are correct that they are used for several models.

Glad to hear your pressure check is holding up.

John

 

[roscottjr]

Re: 1988 Force 125 Lower unit question

Well, here is the update. Pressure test held at 13psi for the entire 45 minutes so Im good there. I pulled it down to 14psi vacuum and it also held for 45 minutes so it looks like everything is great. Now if only my water pump would hurry up and get here I will be ready for the water.

Robert

 

[Frank Acampora]

Re: 1988 Force 125 Lower unit question

Earlier lower units had a smaller drive shaft diameter and seal area under the water pump, although the same cover was used. So you will have two different drive shaft seals with the same outside diameter but a different inside diameter. Since these seals are expensive, if you think you may in the future buy a different lower, save the extra.

 

[roscottjr]

Re: 1988 Force 125 Lower unit question

I always save my extra seals. I place them in a box marked for whatever they were for so I will have them if I ever do need them. However, I hope I never have to replace the lower on this engine but that is a good idea to save the seal in case it is used on the replacement lower if I ever replace them.

Robert

 

[roscottjr]

Re: 1988 Force 125 Lower unit question

Well I got my water pump and got everything put back together but havent had time to water test until now. I ran the engine in a tank and everything is doing great. However, when I shut the engine off I noticed a light tan colored petroleum based substance in the tank. The gearcase passed vacuum and pressure tests as I have posted previously. Does anyone know what this substance may be? I noticed it before I resealed the gearcase as well but only when it was ran in the tank. I didnt notice any at the lake. Could this possibly just be unburnt 2 cycle oil? I dont know why it would be that color but since the gearcase passed all tests Im sure it is not the gearcase leaking again. I also checked the gearcase oil as a precaution and it looks just as it did when I filled it.

Robert

 

[john from md]

Re: 1988 Force 125 Lower unit question

Unburned 2 stroke oil is my guess. Get out on the lake and run it. Check for water for the next couple of launches.

John