Is replacing and transom seal a do-it-yourself thing?

[JonEaton]

Hey all;

Just bought a 1978 Tempest with a 120HP OMC with a 400 Series Stern Drive on it that I'm going to completely restore. But the transom seal is is full of holes and in the past I think the boat had quite a bit of water in it (about to the top level of the oil pan) The trim and tilt are full of water but everything else is okay. Is replacing the transom seal something a mechanically minded person could do with the help of another person? or should it be left to an expert? Here are the pics.

http://gallery.eatonit.ca/album01/P7270006
http://gallery.eatonit.ca/album01/P7270008
http://gallery.eatonit.ca/album01/P8010018

Thanks!

[Titanic]

I have replaced the seal on my 400 series OMC. It really is not difficult at all.
You have to remove all the phillips head screws from the Transom. Pull the rubber boot back over the outdrive. Inside you will see a large hose clamp that holds the boot to the outdrive. Loosen the clamp and pull the complete boot over the drive and lower unit. It will seem a little tight but it will come off and on without tearing. When you reinstall it you will need sealer under the part that seals to the hull. Since you mention a lot of water in the hull,I would check and make sure the motor mounts are solid and has not shifted the engine allowing the boot to be torn.

[JonEaton]

Thanks for the reply. The motor stayed wherever it was in when the trim motor died. Then whoever owned the boat before me installed those "whale tail" things on the lower unit. I think it is the original transom seal, so it was 25 years old anyways, it was about time. Now I have to find a trim motor for it so I don't have to put those things back on, they look retarded on a white outdrive lol

[Billmo99]

The guy that will be helping me suggested that I replace all the bolts and nuts that hold the transom seal on with stainless. Any idea what size these are. My boat is a 72 Stardust cruiser steel hull, and is about 1.5 hours from where I'm sitting at the moment. I'm guessing they are 10/32, about 1.5 inches long with phillips heads. Close?

Bill (new member)

[Titanic]

Sorry, can't help you there. My boat was a fiberglass hull and they were common wood screws.

[StianM]

If something is a do it yourself thing or not depend on your tool's and your skils.

I plan cylinder heads myself.

[JonEaton]

The guy that will be helping me suggested that I replace all the bolts and nuts that hold the transom seal on with stainless. Any idea what size these are. My boat is a 72 Stardust cruiser steel hull, and is about 1.5 hours from where I'm sitting at the moment. I'm guessing they are 10/32, about 1.5 inches long with phillips heads. Close?

Bill (new member)


Exactly, I just finished having the 400 Sterndrive completely rebuilt, sandblasted and painted.. 1500 later, but I put the boot on and yeah, that's pretty much all I needed, that and some really good marine calking.

[mystro]

Exactly, I just finished having the 400 Sterndrive completely rebuilt, sandblasted and painted.. 1500 later, but I put the boot on and yeah, that's pretty much all I needed, that and some really good marine calking.

I'm doing the same after I noticed the ball gears were almost shot *after* purchase :( it's now being gone thru. I did find one very important fact about my vintage 72 OMC-120..you should *never* use the sterndrive for trimming it has no trim, hence those whale tails. It'll wear the ball gears out otherwise and I was told to only shift it at idle when fully lowered so at the price of these gears $765 and $273 respectfully.. I'll follow that rule :)

I hope yours is a different model?

[JonEaton]

I sure hope that price includes the labour.. The entire Ball gear kit (both gears and all the seals) is 185 bucks (US) on boatparts.ca. I'm not too familiar with yours but mine didn't actually need the whale tales. My 78 setup is a "stringer" type which means the whole engine trims with a motor that sits under the very front of the engine (250 to replace) and yeah, with the ball gears, you can't start the engine unless the outdrive is completely down anyways because the ball gears are always turning (spinning the shaft, turn the impellor, suck up the water) maybe yours is closed cooling I don't know, but I think that applies to all of them with ball gear setups. I do have a question for you, I managed to get the boat running, is it normal for the outdrive to be this low in the water? (I attached a pic) With someone sitting in the back, it's almost completely submerged lol

Thanks!
Jon

[Lancerbye]

Hi
I have been reading your thead about the 400 OMC. Yes they do sit that low in the water.They will come out a bit when you are on the run. I had a lot of fun with one of these on a 24ft. 1976 Reinell which I sold last year.does yours have an electric shift. I have rebuilt a few of these and a common problem is the electromagnetic shifting system. Do not have a strong VHF radio or any other load on the same battery system as your leg shift. I have heard of people cruising along and decide to key their radio which causes a load on the shift electrical dropping the voltage to below the release voltage of the magnet, about 11.25volts. you can imagine the rest. The drive disengages, the engine revs up, the operator lets go of the mike, the drive reengages with vengence and if your lucky you only lose the coil spring which is hard to find and costs about $300 to $500.

[JonEaton]

No mine isn't electric shift, it actually had a hydraulic pump in the lower unit, which has since been removed. When I bought the boat it was "as is" and I later discovered that it only ran in forward, and would not shift, well I don't know what happened but the clutch dog was screwed up and my reverse gear was in about 20 pieces at the bottom of the housing, had new gears put in, left the hydraulic pump out (my boat guy says it's not really necessary and just left it out). Funny thing is, I towed the boat up north (about 200km's 100miles or so) and now I can turn the boat all the way left, but only about a 1/3 of the way right. It never ends! It was alot of time and 1500 bucks to get from one to the other.

[h82goslo]

HA!!!! I had to register just to reply to this!!! I had the some problem with my outdrive and its a simple fix!!! Take off the two caps on the sides of the unit (4 bots each) and lift the unit. You will see a 1.5" gear that is your turning gear. Now set the steering wheel strait ( I went lock to lock and marked the center with a piece of tape) and then set your outdrive back down on the gear making sure it is centered. Put the caps back on and you should have your steering back. It was a simple oversite on my part and had me scratching my head, but it was the result of not paying attention to the position I took the outdrive apart from and how I put it back. Good luck!!!

[Slider]

No mine isn't electric shift, it actually had a hydraulic pump in the lower unit, which has since been removed. When I bought the boat it was "as is" and I later discovered that it only ran in forward, and would not shift, well I don't know what happened but the clutch dog was screwed up and my reverse gear was in about 20 pieces at the bottom of the housing, had new gears put in, left the hydraulic pump out (my boat guy says it's not really necessary and just left it out). Funny thing is, I towed the boat up north (about 200km's 100miles or so) and now I can turn the boat all the way left, but only about a 1/3 of the way right. It never ends! It was alot of time and 1500 bucks to get from one to the other.

nice restoration....I see you are in Toronto...where to you boat?...Muskoka/Haliburton?

I'm working on restoring a 74 Starcraft Holiday 18 ft with 140hp Mercruiser....