1997 120hp Force Lower Unit Reseal

[Fishing Phool]

Hi Everyone

I'm getting ready to reseal the lower unit of my 120hp Force Motor. I've read through my aftermarket service manual and I think I'm ready but I do have a few questions.

The service manual says that there are a number of bearings and such that if removed usually get distroyed and need to be replaced. I've only purchased the seal kit. Should I get some bearings too, or can I get to all of the seals that I need to without purchasing extra parts? Any suggestions / tips to make the job easier?

Thanks

 

[jerryjerry05]

Re: 1997 120hp Force Lower Unit Reseal

Never heard of destroying any bearings when resealing a lower.
You figure out where it's leaking?
Just be careful when dismantling.You can destroy the sealing surfaces when you remove the old seals.
You,can't replace the bearings/gears without special tools.
Take your time and work slowly.
Profile?Where do U live? You might be close to someone who can help.J

 

[Fishing Phool]

Re: 1997 120hp Force Lower Unit Reseal

Thanks for the reply.

I have not figured out where its leaking from, but I figure that if I reseal it all, it should be good. Is that a faulty assumption? I do think its leaking though. Here is why.

This is my first boat - Just got it in August

* I changed the oil early September - took it out once after that.
* I opened the drain plug in October to see if water had gotten in the lower unit - afraid of freezing and there was about 3 tablespoons of milky oil in the bottom. I drained out the milky stuff and put the plug back in.
* I ran the motor with the muffs on monthly and just recently checked the oil again, and it was all milky. So I've decided to reseal it.

I would like to know where the leak is coming from. I've seen the posts on pressure testing the unit but I still have questions regarding actually pressurizing the unit. Specifically what fitting do I use to connect the air to the lower unit.

Oh by the way, I live in Lebanon Oregon.

 

[jerryjerry05]

Re: 1997 120hp Force Lower Unit Reseal

There have been a few links on here about making a pressure tester.
Use the search function,it will(maybe)direct you to one.
Carla you out there?? She had pics of one on one of her threads.Maybe she's reading these.
From what you say it's getting water in when you run it on the hose.I'd bet the top seal under the pump housing is leaking.
Just abit around the drain plug,I'd try a new gasket there.
Sounds like it's leaking in 2 places.J

 

[Fishing Phool]

Re: 1997 120hp Force Lower Unit Reseal

Thanks for the input, this is great info.

I think I saw Karla's post along with a few others. She had the red foot pump right? One thing I didn't see in any of the posts I saw was how to actually connect what I'll call the snorkel of my pressure tester to the lower unit.

In trying to figure out how to connect to the lower unit, last night I removed the screw to the oil vent and measured it. This is where I plan to make my connection. It looks like a 3/8"-16 thread (I don't have a standard thread gauge yet so this is a guess based solely on the diameter) - so I think I need a hose barb with those threads. Trouble is trying to find one. Its kind of an oddball configuration. Most hose barbs come with NPT threads. I searched a few fitting suppliers websites to no avail. I guess I'll have to make one unless someone out there has a tip.

 

[Fishing Phool]

Re: 1997 120hp Force Lower Unit Reseal

So I'm assembling my equipment to leak test my lower unit prior to resealing. The key to the equation is how to connect the air line to the lower unit. Here is how I solved the problem. Since I couldn't find any air or plumbing fittings with a 3/8"-16 (coarse) thread, I took a 2-1/2" long 3/8" bolt that had a good unthreaded shoulder on it, and drilled a 1/8" diameter hole in it. Then I cut the hex off the top. I then threaded (2) nuts up to the top of the threaded portion and cinched them down tight against each other with some locktite red. That way I can tighten it in the LU vent with a wrench. I tested the fitting in the LU and it fit perfectly. Now all I need is some tubing to fit the my 3/8" custom bolt fitting, a pressure gauge, and a tire valve to connect my pump to.

 

[jerryjerry05]

Re: 1997 120hp Force Lower Unit Reseal

PICS??????? They always are a help.Trouble loading pics? Contact me or someone here and we'll load them for U.

 

[Fishing Phool]

Re: 1997 120hp Force Lower Unit Reseal

Sure. Pics will follow. I'm still assembling my testing unit. When its ready, I'll post some pics.

 

[Fishing Phool]

Re: 1997 120hp Force Lower Unit Reseal


Hi Everyone,
Here are some pictures of my pressure test assembly. Its consists of:

1.) 3/8"-16 (coarse) thread bolt, with a hole drilled down the middle, and the head cut off (from the hardware store)
a.) There was (1) nut half way up the thread and glued into place with loctite red. (I had 2 as seen in the 1st pic but needed to remove one to get longer threads. I'll explain later)
2.) 3/8" tubing to the 3/8" tee (from work's scrap bin - with manager approval)
3.) 3/8" tubing from the tee to the hose barb and oil pressure gauge assembly (tee - from work's scrap bin - with manager approval, Oil pressure gauge - from my tool box)
4.) 3/8" tubing from the tee to the tire stem (tire stem - from my local tire shop).
5.) 6 hose clamps (from the auto parts store)
6.) A 3/8" rubber cone washer. (to seal the connection to the LU as seen in the fourth pic... This is what required the removal of one of the nuts.) (from my treasure chest)
7.) A bike pump

What I found doing my pressure test.

It looks like the LU was actually sealed pretty well. The only place I saw bubbles was from under the bolt heads that secured the water pump base (one pea sized bubble per 12 secs). So I stripped everything down to the gasket between the base and the LU housing. I scraped off the gasket material, put on the new gasket, replaced the base and torqued everything to spec. I squirted it with soapy water, and bubbles still came out from under the bolt heads. I overtorqued the bolts a little at a time trying to stop the leak, but to no avail (up to 150 in lbs). In fact the leak would move from under one bolt the the other. So my hunch is the lower plate is a bit warped, and needs some machine work. I'm also kicking around the idea of putting sealant on the gasket. What do you guys think? Sealant? Machine work? Both? Something else?

Thanks

 

[Fishing Phool]

Re: 1997 120hp Force Lower Unit Reseal

Well since the machine shops are closed this weekend, I thought I'd try the sealant. I also made a new gasket from some bulk thermostat gasket from the autoparts store.. It didn't work. The base must be more warped than I thought. I guess I'll have to try to find a machinist tomorrow.